RV A/C And Camper Rooftop Air Conditioner Maintenance, Troubleshooting, and Repairs
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Camper Trailer and Motorhome AC Servicing
Since the majority of motor homes and camper trailer A/C systems are used during the hottest time of the year, it is a must to keep them in good operating order. Just cleaning and replacing the filter is not good enough.
There are certain procedures for guaranteeing the maximum efficiency of your motorhome or camper trailer A/C unit. These steps are not as difficult to perform as you might think.
Cleaning the condenser and evaporator can and will make a huge difference in the cooling ability of the motorhome or camper trailer unit. Lubricating the fan motor may help extend the life and performance of the unit itself.
You will also learn a little about how these cooling units differ from regular household units by following the tips in this article.
Keeping Your AC Cool
Brands and Types of RV AC Units
There are several main producers of rooftop units. Coleman RV air conditioners are common on many motorhomes and camper trailers. The same can be said for carrier units, as well as Duo Therm A/Cs. Dometic made one of the first rooftop air conditioners, as well as, camper refrigerators and ice machines.
Thankfully, all of these units are similar in function and design. Some of these cooling units may even be identical under the shroud.. Being familiar with household AC units will aid you greatly in servicing and repairing repairing your air condition system.
Repair Manuals for Camper Trailer AC Units
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Troubleshooting Camper AC Units
Before beginning any repair or maintenance steps it is helpful to familiarize yourself with the main components of the rooftop AC unit itself. A fan motor circulates the air from the interior of the motorhome or camper trailer through the AC unit where it is cooled and then returned into the RV interior.
The compressor performs the job of circulating the Freon through the condenser and evaporator cooling fins and the cycle is repeated as the thermostat setting deems it necessary.
Both the compressor and the fan motor use capacitors to provide a high voltage charge to get them moving.
Often, only one capacitor is used for both fan and compressor. It the capacitor goes bad, neither the fan nor the compressor will start. This part is easily replaced and is not very expensive in most cases.
Rooftop A/C Shroud
Rofftop AC Shroud Removal
In order to clean or repair the AC unit, it is necessary to remove the shroud from atop the unit. Ordinarily this is a simple job requiring only a Phillips screwdriver or small wrench. Remove the four screws or nuts from the AC shroud and carefully slide it up off of the unit.
If the shroud is old, it may be cracked around the retaining screws or the vent holes on the sides and back. Now is the time to repair the bad spots before replacing the shroud.
A good quality epoxy cement, or other glue made for plastic repairs, should be used to reinforce the weak or broken place before replacing the shroud. It is also advisable to use wider washers on the shroud retaining screws to prevent further cracking.
If the damage seems too bad to repair, a new shroud may be the only option. A broken RV A/C shroud will decrease cooling efficiency plus pose a danger of flying off while the camper is in transit .
Accessing the Fan Motor and Fans
RV AC Replacement Fan Motors and Parts
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Servicing and Repairing the Fan Motor
With the shroud removed, it is easy to inspect the fan motor for any repairs or maintenance needed. Before doing any repairs or maintenance to the rooftop AC be sure to turn the electrical breaker off or unplug the motorhome or camper trailer from the electrical power source. The starting capacitor may be still charged with high voltage, so be sure not to touch it with the bare hands.
The fan should spin easily when turned by hand. Even so, it is a good idea to oil the bearings and clean the accumulated debris both front and rear fan blades. It may be necessary to loosen the fan motor from its mountings to fully access both ends of the motor bearings.
If the fan motor has oil tubes to lubricate the fan, then simply put a few drops of machine oil in the tubes on either end of the motor. If the motor has sleeves instead of ball bearings, you may still dribble a small amount of oil on the sleeves where they contact the fan motor shafts. Even a small amount of oil will do wonders for these types of fan motors.
If the AC fan motor still seems to start slowly or needs a nudge to start working, it is recommended that you replace it with a new one. If the fan motor has oil tubes evident on each end of the motor, it may be rebuilt and replaced for much less than buying a new one. It all depends on the particular unit on your camper.
If either the fan motor or compressor fails to start a new starting capacitor may solve the problem. Be sure to order the right size and voltage for your rooftop unit. These capacitors may be found at your local AC parts dealer or you may find them online for greater savings. Be careful when handling these capacitors as they may still hold some electrical charge.
This Condenser Needs Cleaning
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Cleaning the AC Condenser and Evaporator
It is recommended that you clean the condenser and evaporator fins every couple of years to maintain the efficiency of your RV air conditioner. Eventually, the cooling fins on these units will become clogged with dirt and dust.
Use a good spray or foaming cleaner, such as those shown here, to loosen the debris and then use a wet/dry shop vac to remove the looseneed dirt and dust. Be sure to cover the vent leading down into the RV interior to keep the grime from seeping down inside.
Be careful not to bend these fine fins as they will bend easily. A special fin comb tool made just for straightening these fins may be purchased from an AC parts dealer or through links on this page. Once again, be careful when performing this maintenance procedure.
Bent fins inhibit the flow of air through the unit, so be sure to keep them as straight as possible using the fin comb.
Oh No! Not A Bad Compressor
RV AC Compressor Repair or Replacement
The most costly and difficult part of an AC unit to replace or repair is the compressor. In many cases it is advisable to simply replace the unit instead of trying to replace the compressor. With a new unit costing about $500 to $600, spending $300 to $400 dollars for compressor replacement doesn’t make much sense.
The labor involved, plus the co prohibitive cost of the compressor, can almost pay for a new rooftop unit. These units are very easily replaced and will have a new warranty to cover future repairs for a few years. This is usually the correct option when the compressor goes bad.
The alternative is to find a used compressor. Unless you are skilled in replacing the compressor and are able to recharge the unit with freon, this is not advisable. This step is entirely up to your skills and pocketbook. There are used RV A/C parts available online and locally in some cases.
Now, Enjoy Your Camping Trip
If properly maintained and serviced, your motorhome or camper trailer A/C will last for many years of camping excursions. Most maintenance can be performed by the owners if they have basic mechanical skills. Understanding how an AC unit works may just save that camping trip you have been looking forward to for so long.
Be careful and take photos of the unit before removing any parts which may cause confusion during reassembly. Be sure to protect the roof of your RV while servicing your rooftop unit. Good luck with your repairs and maintenance.
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CommentsLoading...
It sounds like the compressor is getting hot, Bill. This makes it harder to start back up when the thermostat kicks it on. It's possible the capacitor is not giving the compressor enough of a charge to kick it on, but this is unlikely if it starts fine when cold.
You might try a new capacitor to see if it is the cause of the problem. Most of these units use the same capacitor to start both the compressor and the fan.
I hope this helps!
The air conditioner in our 2008 Arista motorhome has never cooled very well. There is barely any air coming out of the vents, albeit cool air! The dealer ways there is nothing wrong with the A/C. Are there are some things we can try on our own? Perhaps the vents are blocked somehow. How would we check that? Any suggestions are welcome, as we live and travel in Texas which is very hot in the summer!
This sound like the coils in your unit are clogged up. Remove the shroud and clean the coils with a strong cleaner such as 409 or a coil cleaning solution found by clicking on the Amazon ads on this page. If the coils are dirty it can inhibit the flow of air through the coils thus making the airflow less than it should be.
Thanks for reading!
i have a boliy 3600 geni and i just bought a new(used) camper with a 15k btu a/c unit in it. it ran my 13.5 just fine and i put in a separate capactor and it still doesn't run it i don't know if it was the right one i have a buddy that does hvac and he gave it to me to try the generator is rated for 3300 watts wich i thought should be plenty to run it. it runs for about 2 min and then kicks the overload out on the geni. it seems like the a/c is bogging in those 2 min. any ideas? thanks
The capacitor doesn't seem to be your problem. It is only for starting the compressor and fan motor. It is either the fan motor but more likely the compressor. Use an amp meter to check the LRA (Lock Rotor Amps) on the compressor which should match the numbers on the compressor label. This will tell you if the compressor is overloading. The same for the fan motor. Hope this helps!
When camper AC reaches thermostat setting it shuts off as expected and then comes back on and off repeatedly and keeps triggering until I lower the thermostat and it stars all over again! Is there something wrong with the thermostat or something with the sensor/sending unit?
This sounds like a thermostat problem, Tom! Check the thermostat sensor which should be in the area where the filter is placed. Sometimes these get bent and do not let the thermostat swing properly.
Also check the thermostat connections for loose wires. Hope this helps you out! Thanks for your time!
I have a 2007 5th wheel rv. In the past 1 and 1/2 years the compressor keeps going out in my Carrier 15,000 unit. Is this caused by electrical surges? I've already replaced it twice and Carrier says they will not warranty it again. It started kicking the breaker off again last night and the fan will run but the compressor kicks the breaker
This sounds like you have low voltage Cindy! If you are using the same hookup all the time, this may be the case. Low voltage/and or amperage may cause the compressor to go bad if the AC unit operates for long periods of time.
If the lights dim when the compressor kicks on, it indicates insufficient electrical power to operate both fan motor and compressor efficiently.
Be sure your AC unit is not icing up by checking under the air filter for ice blocking the coil. Running the thermostat too high will cause the ice to form and once it blocks the airflow the compressor may run until it kicks the breaker off.
Electrical surges could possibly affect the compressor but this would be a long shot unless you live in an area with poor electrical service. Good luck!
I talked to a tech a carrier and was told if the fan motor is going bad it will cause the compressor to blow the fuse when it gets too hot. We took the cover off today and stsrted the fan by hand and the compressor did not kick out the fuse. I turned it off and tried to restart with out the help of spinning the fan and had to turn off the unit before it blew. Capacitor bad?? They said the fan spun easy when they turned it
Yes, this sounds like a bad capacitor, Cindy! The capacitor is used to give a boost to both the compressor and fan motor during the start up and is probably not giving enough charge to start both.
Changing the capacitor is easy and relatively inexpensive. I hope this solves your problem with kicking the breaker or fuse!
I have a rooftop unit on a Travelstar 23RBS. The unit quit blowing cold air last week. The blower runs great, but it is blowing hot air (it's in the 90's here). In the evening when it cools a little, I can put it on very low cool and the compressor doesn't cut in. Then when I turn the temp down I can hear the compressor cut on, but it still doesn't pump cool air.
Ideas?
Your RV AC unit appears to be low on freon or else the compressor may be malfunctioning. It could possibly be a relay but probably not. Sorry, but without seeing it run this is the best suggestions I can give. Good luck!
I want to thank you for your help...after reading this web page I got on the right track in getting my AC fixed. The new capacitor did the trick!!
Wonderful news Cindy! So glad you were able to get your AC going again! Thanks for letting me know about your success and for reading my article. Good luck and enjoy your camping trips!
Hello Randy, to get started, our RV Air-conditioner isn't functioning properly, it WAS functioning perfectly fine last year... Problem: After turning it on, it will blow cool air for @ 1 minute, then something happens and it gets quieter, and the cool air gets warm, then it starts getting hotter than outside air. The coils are clean and the fan does blow perfectly fine without problems. It's hooked up to a 30A fuse all by itself so it's getting enough electricity (I can run the microwave and TV at the same time without a problem). It's a Coleman Mach (I don't know the exact model # or anything like that).
Please help with any input you can provide!
< Thanks >
Hi Ben! The reason the AC gets quieter and blows hot air is because the compressor is overloading and kicking off. After it cools down the compressor resets and it will run again for a while.
While my diagnosis is not a sure thing, it sounds as if the compressor is bad and is locking down after it gets too hot. If you know someone with an amp meter you can check to see if the compressor is drawing more amps than it is supposed to.
The amperage it normally requires to operate normally should be listed on the compressor or on the AC chassis itself. Not good news, as installing a new compressor may be cost prohibitive. Please let me know what you find out if I am wrong in my suggestions.
Thanks for checking out my article and good luck with your AC!
Our Carrier RV A/C is putting out foul smelling air, like Dirty Sock Syndrome in a house A/C; it still cools fine but it just smells bad. We don't smoke, don't have pets in it and clean the filters; we do the majority of our cooking outside as far as "absorbed odors" go. Anyone have any suggestions, thoughts?
Hello Toni! This sounds as if the coils in your AC are very dirty and are letting condensation form, therefore causing the air flowing across the evaporator coil pick up the odor and blow it down inside of the RV.
If your RV AC has a drain it may be blocked, causing water to stand inside of the AC unit and also causing a bad smell to be blown down inside of the RV.
Cleaning the coil is a fairly simple job and will probably solve your problem. Follow the instructions in this article and clean the drain if it has one.
Hope this gets rid of your bad odor. Thanks for checking out my articles.
Have a 13,500 coleman a/c unit. It work for about 10 to 15 minutes then kick the braker off. In that time it cool the camper from 100 down to 75. I can keep it running by turn the fan on for about three minutes. The problem I have is after the temperature out side drops to 99 the unit will run all night long as it should. It when the temperature is above 100 it will not run right.
No ice, coils cleaned. What do you think
It does sound strange for your RV AC to trip the breaker this way, Robert! It is possible the breaker is faulty or is not providing enough amps to run both the fan and compressor until the outside temperature drops enough to cycle the compressor on and off.
However, the compressor itself may be drawing too many amps of electrical power which will eventually cause the breaker to trip off. The only way to find out if your compressor is drawing too many amps is to use an amp meter.
If it draws more amps than indicated by the specs given on the label, you will know the compressor is the culprit. Changing the breaker to a slightly higher amperage may solve the problem, but the compressor may be getting worse and this will only prolong the eventual demise of the unit.
I will study your problem and check my sources for another cause for your problem. I will post anything new here. Please let me know if you find out if something else is causing the problem. It helps others who read these posts with their own RV AC problems.
Thanks for your time!
Randy Godwin
Have changed the breaker to a house unit 20 amps. Line straight to plug cord. It been doing it for a year. Have even tried to put cover over unit with wood with space for a flow. Am about to shoot water on compressor. It is on a truck camper larson. I'am a drag racer and only need it to work during the heat of the day. Did put a low amp started a year ago and help get it to run by run the fan for the three minutes. thank for the information
it has me stumped.
Me too, so far, Robert! I consulted another AC guy and he can't figure it out either. He did ask if you could check the temperature of the air when the compressor is running. Sometimes the air will be very cold when the freon level is getting low.
For the AC to cool the air from 100 down to 75 in only 10 to 15 minutes seems rather quick. So check the air temp first!
Is the compressor getting really hot? Perhaps running the fan cools the compressor down enough to let it continue working. If so, this is not good news!
Randy
I found a splice in electrial line. It seen work better. I know it cool down fast but truck camp maybe 36 sq feet with bunk over truck shut off. Will know this weekend.
Thanks
Robert
Keeping my fingers crossed, Robert! Hope this solves your problem! Thanks for the update!
Randy
when I turn off my ac the compressor keeps running, I turned it in fan only and it still blew cold untill it froze up. the only way I could git the compressor to go off was to throw the breaker
This appears to be a switch problem, Tom! Depending on the make and model of your RV AC, the switch may be shorted out and is allowing the elec current to be supplied to the compressor at all times.
The inability to shut off power to the compressor using the off setting on the switch is an indication of a shorted switch! If you are familiar with using a multimeter you can check the switch before buying a new one! Order one online to save a bundle of money!
Thanks for reading!
Webb White asks : "How do you test a roof mounted RV A/c Capacitor? Mine won't kick on with the Generator running. Tries but won't run."
No links WW, sorry!
Use an ohm meter and use a high setting. Unplug connections and check the multimeter readout. The ohms should go up high and then drop to 0. Reverse the multimeter leads and check again. If the results are the same, the capacitor is good!
Sorry about the link!
Hi Randy, I'm a new at this, my problem is #1 ac fan start but the compressor kick on and off every 10 sec., we have good voltage all coils and fins inside and outside are clean. Model 15000 Colman w/hp rv 06 country coach. Any help would be grateful, thank
Hello Clyde! After discussing your problem with another AC troubleshooter, we decided the problem is probably the capacitor! It is apparently trying to start the compressor while running the fan and doesn't have enough of a boost to run the compressor! Therefore the compressor kicks on but fails to run and repeats this cycle.
My response to the question right above yours tells how the capacitor may be checked with an ohm meter(multimeter). If the capacitor turns out to be good, the problem might be the thermostat! I would check the capacitor first because it is a fairly inexpensive and easy replacement in most cases.
If this doesn't solve the problem, please let me know!
Thanks,
Randy
MY COLEMAN ROOF AIR CONDITONER IS NOT DRAINING THE WATER OUT AND IT IF COMING INTO THE CABIN. I ASSUME THERE IS A PLUG OR DRAIN THAT I NEED TO UNSTOP BUT I CANT SEEM TO LOCATE THE DRAIN OR PLUB. ANY SUGGESTION AS TO WHERE TO FIND THE DRAIN WILL BE APPRECIATED.
A common problem with rooftop RV A/C units, Don! Depending on how old your ac unit is, it may or may not have a drain line! If it does have one, you should be able to see it leading down from the bottom of the unit.
But many of the newer AC units do not have a drain and depend on the fan motor to spray it out through the back of the unit! If the coils are very dirty or clogged, the water cannot be ejected and will pool up until it has nowhere to go but down through the vent.
This is usually the problem with the newer models! A good coil cleaning should solve the problem! Follow the instructions in the above article to do this! Otherwise, make sure the drain line is clear if your unit has one!
I hope this will remedy the problem! Thanks for reading!
I have a Duo therm roof top ac unit. This problem just started happening. Everything works fine and the ac cools good during the cycle but when the thermostat cuts the system off the compressor will keep running and you have to cut the breaker off to stop it. I have 7.5 volts at the red wire at the thermostat. Is there a way to bypass on the thermostat to test if the thermostat is the problem ? I have checked everywhere on the net and can't find a specific solution to this problem.
Yes there is Jim, but I will have to research a bit to give you the proper method of doing so! But the thermostat may not be your problem as this sounds more like a relay problem.
I don't have much time right now because of the Thanksgiving festivities but will try and back to you as soon as possible! Please check back and comment if I haven't responded by tomorrow!
Thanks!
Randy
Randy, Where would the relay be at ? All I have been able to find is the two capacitors in the metal box. This is on my RV. I didn't think that the duo therm had a starting relay. That was my first thought that the starting relay was bad and sticking but someone told me that they didn't use a start relay. I'm not sure. Thank you. Hope you didn't eat too much Turkey. Well, Dallas Cowboys got beat. ( again )
Hello again Jim! I am not very familiar with the Duo-Therm AC unit but I assume they are similar to the Coleman units! I will check with my expert and see what I can find out! I will come back and tell you what I found!
Randy
@Jim-Back again, Jim! My fellow AC advisor seems to think the problem is in the switch! It does make sense as to why the power to the compressor is not being cut off.
Barring this, it can only be in a relay or the thermostat! You can check the switch with a multimeter to see if the circuit is broken when the switch is off! Hope this helps you out!
Thanks Randy for all your help on this site. I will check it out.
You're welcome, Jim! I think this will be a simple fix if you can isolate the problem. Let me know what you find out, if you don't mind! This may help others to repair their own AC units.
Thanks for stopping in!
Randy
Randy, when you say switch or you talking about the starting relay ? I found what I guess is the starting relay. It is a small electronic box attached to the terminals of the smaller black capacitor. It is labled motor starter on the side. It is only about one and half inches by one and a half inches by approx 3/8 thick or a little less. Can you tell me off hand how I would check the electronic relay with a multimeter ? or can you check it with a multimeter since it is electronic ? It has got to be the thermostat or the relay but I'm not sure about how to troubleshoot either one. I wish they would stick with the old mechanical relays instead of the cheap made in china throw away and replace electronic parts that don't hold up. Thank you.
No, Jim! I am referring to the control switch which furnishes power to both fan and compressor! The compressor should not run with the switch in the off position! A short in the switch would enable the results you are experiencing! Here is a link to a wiring schematic probably similar to yours.
Click the parts list on the right side of the page to access the wiring schematic, Jim!
Randy
Ok Randy, I think I have the problem fixed. I took the thermostat off and I had some non conductive electrical contact parts cleaner and I sprayed the off switch good with the cleaner and worked the slide switch back and forth a few times. I connected the thermostat back up and ran it thru a cycle and when it cut off the compressor cut off with it. How so simple. Wished I got paid by the hour to fix my own stuff ! One problem in my RV that I suspect could have led to the problem is that the factory mounted the thermostat above the kitchen sink where the steam and humidity from washing dishes probably resulted in the slide swith becoming corroded and/or attracting dust over time even though it is sealed pretty good. This might be something that other people might run across and one for your books !
Another solution as crazy as it sounds relates to the ac not draining the water properly when the unit cuts off on a hot day. I live in East Texas and during the summmer we can go a long time without rain. My unit wasn't draining properly and got on top of the rv and took the cover off of the unit and ran a stiff wire all the way thru the drain channel to see if it had an obstruction. A Rain frog came out of the channel. He was making himself a home in the wet drain channel since it was so dry and no rain for a long time. They are bad about getting in my unit in the summer time. A simple thing as a rain frog in your drain channel can cause a problem. Thank you very much for your help. It's nice to know that people are willing to help each other in this world today.
Great news Jim, and thanks for relating the fix! It is often a simple problem which causes us the most grief! Your helpful comments and suggestions will certainly aid others having a similar rooftop AC unit problem!
Yes, the older RV AC units have these drains and the little tree frogs (we call them rain frogs here too) may seek out such a damp place in dry weather!
It IS good to know that most people are very glad to help others! Thank you for the info!
Good Luck and stop by again!
Randy Godwin
where is the capacitor located generally on these rooftop units? i have a duo-therm and after reading all the inputs on your page i think my problem may be with thecapacitor or servicing. dont know if they can be serciced so will try the capcitor first.
Hello fruby59. I thought I had a photo of a capacitor on this article but I was wrong. I will try and put one on this and my other related A/C repair articles.
But until I do so, the capacitor is usually located in the area behind the control panel. It resembles a dry cell battery in appearance with two connection points on top.
Be sure not to touch the connections as the capacitor may be charged. Hope this helps you out.
Thanks for reading!
Randy
thankyou so much, so it must be accessed for the inside. i appreciate it and will let you know how it works out. this is an awsome sight you have and i will be frequenting it a lot.
@fruby59-Just remove the shroud and a cover is easily removed on the top area of the unit. I mistakenly said behind the control panel because I was thinking of a wall unit.
On occasion, the capacitor will be in plain view, but in many new units it is beneath the cover where the electrical wires lead to the fan motor and compressor.
Still looking for a good photo and may have to take one to display this info. Thanks for letting me know I need a photo illustrating the capacitor's location. And good luck on your repairs.
Randy
My ac runs for awhile and it will start leaking in the trailer what causes this.
A common problem, Heath. If the rooftop RV AC unit is an older model it may have a drain which can become clogged. Newer models disperse the excess moisture back into the air.
In either case, the unit needs a thorough cleaning. When the coils become clogged with dirt the moisture cannot be dispelled through the fins and into the air.
The water collection area on the bottom of your RV AC unit eventually becomes full and leaks water down through the vent into the RV.
Remove the shroud and clean the coils with a good coil cleaning product. Be sure to clean the debris and dirt from the bottom of the unit too. Be sure the power to the AC is off while doing this maintenance. If your unit has a drain, you will see it while cleaning. Make sure it is clear and your problem is solved.
Good luck and thanks for reading!
Randy
my ac run for 4mins and stop only to start up in 20mins again.i've changed the 20uf capacitor in it to 30uf but the proplem is still unsolved ,i've set the thermostart to many level but there's no changes; is it a compresor problem pls help me it is a mobil ac
Hello Matthew! It sounds like your compressor is kicking the overload and when it cools it works for the 4 minutes until it gets hot again. If the fan starts easily, the compressor is suspect. Sorry, I cannot offer you a better diagnosis with so little info!
Randy
i changed d overload in my ac some weeks back.bcus it cools only for seconds befor blowing only fan.but it get worst after changing d overload.it dim d whol light to d lowest voltage.so i've to replace d overload with dat old one i changed from it,dou with a new capacitor.but now it only cool for 5mins befor dropping only to pick up in 20mins.its 9000btu.what 'll i do help me pls
It may be the compressor overloading after it runs a short time, Ononenyi. When it cools down it will run for another short period. An amp meter is needed to check to see if the compressor is pulling more amps than is required to run it normally.
Since the fan is still running properly it appears it is not the problem. A bad compressor is not usually worth replacing because of the expense. Good luck and feel free to ask further if you need more info.
Thanks for reading my RV repair hubs.
Randy
I too have a roof-top duo therm that has stopped working. I can hear a faint clicking from the unit when the thermostat is switched on. It's only a couple of years old. Ideas? Thanks
@Matt-Does the unit work at all? By this I mean, does the fan run or does the unit do nothing at all when turned on? More info would assist me in helping you find the problem.
Randy
it does nothing just the clicking when you first flip the thermostat
or its a single click i should say
@Matt-The clicking is normal and is caused by the thermostat attempting to activate the compressor to come on. Since neither the fan nor compressor runs when the switch is turned on, then it appears as if the electrical power is not getting to the RV AC unit.
Check the breaker panel to be sure the power is going through the breaker and on to the AC unit first. In some cases the breaker will appear to be good but is not allowing the electrical power to pass through.
It is possible for the electrical connections in the ceiling panel assembly to be loose or the wire nuts may not be tight enough. If all of these connections seem okay the control switch itself may be shorted out.
A multimeter is very useful for checking the connections and switches for proper functioning. If you still cannot trace down the problem, please feel free to ask for further info.
Randy
I have a rooftop rv ac.
It started to run with both fan and compressor on fine during the first cycle. But when it reaches the proper temp the fan shuts off but the compressor keeps running until the breaker kicks trips. Any ideas what might be wrong?
@David--The fan motor should not stop running unless it is a special energy saving option particular to your RV AC unit.
If the fan motor bearings are worn or in need of oiling, the motor will eventually overheat and stop turning. This adds extra load to the electrical supply which causes the compressor to kick the breaker.
You may be able to oil the sleeves or bearings on your fan motor and try running it again. If this isn't your problem, please feel free to ask for further info on your problem.
Thanks for reading!
Randy
I have a 1991 fleetwood prowler that my husband got about for months ago and the ac unit worked great and now it doesn't wasn't to work. It sounds like it wants to kick on but then it stops. Is there anything I can do to get it started again and I'm also very sure its the original ac.
Hey Jayme, it sounds like the fan motor is stuck or the capacitor may be bad. Try removing the ceiling cover where the filter is located and give the fan a spin and turn the unit on "high cool". If the fan doesn't spin easily when turned by hand the bearings need oiling on the fan motor. If the unit operates normally after spinning the fan and the fan spins easily by hand, a new starting capacitor is probably the culprit. An easy an inexpensive item to replace,
Have you tried running the unit in the "fan" mode only? If so, did the fan operate at all? Try the above suggested procedure and tell me what happened!
Thanks for the question and for reading my article.
Randy
Thank you I will try that. Also does everything in the trailer needed to be of before I try this?
No, Jayme. Just be sure your hand is not still on the fan after spinning it when you turn the unit on. Give it a brisk spin to keep it turning until the unit is switched on.
Randy
Ok I took the cover of where the filter is and I don't not see a fan at all. Is there more things that need to be takin off for me to get to it.my husband works alot and doesn't have time to look at it when he does come home.
The fan is a "squirrel cage" type fan, Jayme. Not a typical propeller type such as in a window fan. You will have to reach up inside of the air duct leading down through the roof until you fell the edges of the blade fins on the fan. If the bearings are fine, you should be able to easily spin the fan with little effort.
In some cases there are several screws which have to be removed from the ceiling assembly and the knobs pulled off to access the fan vent.
This link will show you pictures which may help you understand better what i am referring to.
http://hubpages.com/hub/Where-To-Buy-And-How-To-In
Try this and get back to me.
Randy
Ok so I did spin the fan and turned it on high cool like you said but there was still nothing and the fan did spin easy.
Let me consult with a fellow AC troubleshooter and get back to you Jayme! What make AC unit do you have in your RV? And does it kick the breaker if left on or just stop sounding as if the compressor is trying to run?
Randy
The breaker has cut off a few time when it was working and the make is a coleman.
Thanks Jayme, I suspected as much. If you don't see my answer here tomorrow, please post another comment here and remind me. I am swamped with questions on many of my RV repair articles and I tend to forget to respond when it is this busy.
I have a hunch what your problem is but haven't received an answer from my fellow RV AC troubleshooter. Don't give up yet! LOL!
Randy
I understand I'm in no hurry its been broke for the past two months.we are living in it right now but its not to hot out just yet we liveing in it for the time being we have the windows open all day long with a fan running.don't get yourself wore out you have a life to live as well.thank you so much for helping.
I wish I could actually examine your AC, Jayme. It could be a capacitor or a relay which is causing you problems but I don't know if you would be able to check the items yourself.
Do you have ant friends capable of using a multimeter to test these electric parts? I am still checking into other possibilities, so don't give up yet!
Randy
I have a Coleman 15000 unit that is about 12 years old. It worked good through last Fall, but recently tried to use it and it does not cool. I can get the fan to come on. However, when I try to turn on the a/c I get a clicking sound from the relays on the control board in the plenum box. The thermostat will then cycle periodically trying to turn on the a/c but you can here the relays just clicking. I have checked the voltage and get about 119volts, and when the thermostat tries to start the compressor it drops to about 116volts. I was thinking it could be the capacity on the compressor, but per you other feedback, this might not be the case since the fan works, or could it just not be strong enough to start the compressor? Or could it be the control board in the plenum where the relays are and that needs to be replaced? Would appreciate you guidance.
Hello Dave,
Since the Coleman unit is fairly old, I would suggest you check the amount of amps being pulled by the compressor when it is attempting to start. On the compressor itself, or on a separate plate, there will be information which gives the amount of amps needed to start and the amount needed to run.
It will be listed as START AMPS and RUN AMPS. You will need an amp meter to check the amperage for when the compressor is trying to start up. If more is being drawn than indicated, the compressor is bad.
I doubt it is the capacitor but you can check it with a regular multimeter. Set the meter on ohms and place the probes on the separate poles of the capacitor. If the random numbers start high and gradually become lower when you check this and then when the probes are reversed, the capacitor shows to be fine.
It's possible a relay is bad, but they sound like they are doing their job. I hope it isn't the compressor, but with the age of your unit it sounds as if it may be the culprit.
Good luck and please tell me what you find out.
Thanks for your question and feel free to ask for more info if needed.
Randy Godwin
I have a 2008 puma and the a/c has been working fine. went and set it up a couple of days ago and noticed today that the unit is cooling but is making a loud noise. it was so loud I turned it off and we had to come back to the house tonight because of the heat. Any tips on what it could be? thanks
Well Joel, it is probably the compressor or the fan making the noise as these are the only moving parts. I would suggest you remove the shroud and have a look while the unit is running.
It may be the fan blades striking the side of the metal shroud or the compressor could be going bad. Let me know what you find out when you remove the shroud and I"ll try to help.
Randy, Per your advise last week, I checked the unit and the compressor was bad. I replaced it with a new Coleman 15k btu unit today and got it running, cooled nicely. A question, I got it working and it cooled when I set the thermostat on low fan, but when I set it on high fan, I got a buzzing sound in the thermostat and it stayed on low fan and kept cooling. What could this be?
Hello again, Dave. I was afraid the problem was your compressor, but was hoping for a different result. Let me ask my go-to guy about your problem and I'll get back to you. This is a new one on me!
Randy
Hey Randy, useful hub yah got... How about telling me if roof insulators make the AC cooler?
Yo, debugs! Any type of insulation on the roof will help the AC perform more efficiently! This is especially true for an RV sitting out in the direct sunlight.
Thanks for stopping by and for the question!
Randy
So I have a 2003 Ford E450. It has a carrier roof unit with 3 fans. The fans work, but the air is not cold. I adjust the thermostat up front and it makes a clicking noise. I think this could be the switch to the compressor to turn on, but not sure. What do you think would be the 1st step in evaluating this a/c unit? Recharge? Listen to the actual a/c unit for the compressor kicking on? Sorry this is a newb question. Thanks in advance.
Yes Andy, the clicking in the thermostat is the signal for the compressor to start running. The best way to check the compressor is with a clamp-on amp meter.
The meter will tell you how many amps the compressor is pulling when it is trying to start. The start/run amps normally required for your unit will be indicated on the compressor or some other plate on the unit.
If it pulls more amps than the displayed specs indicate is needed, the compressor is bad. It could also be a relay but you will not know until the voltage to the compressor is checked.
I hope this helps you find your problem. Any other info you can give me might help find the problem. Feel free to ask for further info.
Randy Godwin
Thanks. So there isn't a port where you can just check the charge of a/c? I was surprised that the e-450 didnt have regular a/c and only used the roof one... I will look into the voltage. Thanks again for the recommendations.
These units use a sealed system unlike an A/C unit in a car or truck, Andy. A piercing valve is usually necessary to recharge these type RV rooftop AC/ systems.
Good luck with your repairs and thanks again for checking out my RV repair articles.
Randy
we have a duo therm unit, it doesnt shut off when thermostat reaches temp. What could this be??
Hello Christina, it will be either a malfunctioning thermostat or a relay. I would suspect the thermostat is the problem as it determines when the compressor runs or not.
It is simple and relatively inexpensive to replace the thermostat in your particular Duo Therm unit. I would try this first.
Thanks for the query,
Randy Godwin
I have a good one for you, I have a 13500 Dometic, Duo Therm Brisk Air. New unit as of last year. Air was functioning properly last year. I moved the RV to a new location and was too far from the electrical service so I had to extend the trailers power cord. I did this properly using 25' of 10/3 wire. Everything in the unit is working fine, all circuits have been checked from end to end. They all show correct. The air conditioner is cooling fine......except.....the fan inside is running backwards, it is blowing out of the return, and sucking air in through the vents. HELP
Hello Jim. The only thing I can think of which may have a bearing on your problem is you may have reversed the polarity by crossing the wires in your extension cord.
Some electric motors will run backwards if the polarity of the wire connections are reversed. But a good multimeter should show this if indeed this is the problem. Let met know what you find out!
Thanks,
Randy
I had people tell me that on 110v that it didn't matter, I reversed it anyway...... nothing. Thanks for listening. I'll let you know when I finally figure it out
Thanks jsdiver! I didn't really think it was the problem either. I did want to eliminate the possibility since you mentioned the extension cord.
You also didn't say if you had tried it at the original plug in again to see if it had made a difference. Thanks for the question and please do tell us what you find out.
Randy
I have a Duo-Therm brisk air 13,500 btu roof unit. Yesterday it was running fine, I left and went to the store and when I returned home the unit was making a humming noise, was not blowing air and was hot inside. I turned it off and waited about 5 minutes and turned it back on, now the fan will only turn when its on fan high or ac high and it turns slow. I can feel cold air from the vent but it is barley moving. I removed the cover on top and opened the box to look at the capacitor and both the capacitor and the other part in their are leaking a fluid. Does this mean they are bad, and what is the name of the other part. I have not checked with the multimeter yet as I am new to this and am going from what I am learning here and I did not see anything about leaking. Any help would be great.
Just to update. I checked the capacitor with the multimeter and it started high then went down. Same when reversed. I think the other pars is a motor run capacitor. Is their a way to test it?
Hello Kevin! Some units use two capacitors, one for the compressor and the other for the compressor. Both are tested in the same manner you used to see if they are good.
Otherwise, your fan motor may be the culprit. Try spinning the fan motor by hand before switching the unit on high fan to see if it will start turning faster.
If it is hard to turn by hand, it is the fan bearings getting hot and causing the motor to stall. Any leaking fluid is a bad sign, whether coming from the capacitors or the compressor.
I spun the fan and it turns easy. I spun it then started the fan on high and it still runs the same speed. I checked the motor run capacitor and it looked good too but they were both wired still when i checked them, so i unplugged both of them and neither one shows anything on the meter now. The compressor is still coming on so are they suppose to hold the charge when they are unplugged? Something tells me it has to be a capacitor so i am going to go to the RV dealer today and have them checked. I think the leaking fluid was not a leak at all but some kind of gel or something the capacitors set in. If you have any other suggestions let me know please, and i will update later what i find out at the dealer.
@Kevin-The capacitor must be holding a charge if the compressor starts up easily as does the fan. There may be a relay which is not allowing the fan to run at different speeds or the fan switch itself may be the problem.
Let me know what the dealer says about the capacitors as this is something of an enigma to me!
Thanks for relating your problem as others may benefit from your experience with your RV AC repairs.
Randy
I have a coleman ac top unit. I turn it on and it runs fine for 10 minutes. After that it trips the breaker. Well today it was tripping the breaker in the house. I am about to beat it with a sledge. I bought the rv in 2004. I never used the ac 1 time. So naturally now that i want to use it in the summer it wont work lol.
Yo Raider! Are you using an extension cord to supply power to the AC? What size breaker is in the house? Is the compressor cycling on and off as it should? A little more info is needed!
Randy Godwin
No extention cord. It comes on as it should and runs about 10 minutes. Then it kicks the breaker. I went and bought another breaker switch of the same kind. Still same problem. I had tried it at a campground plugged directley in and would not work.
Too bad, Raider! The only thing I can suggest is to check the compressor with an amp meter to see if it is drawing too much power. The run/start amps should be listed on the compressor or on a small plate inside the unit.
I suspect the compressor is pulling too many amps which causes one of the breakers-either in the camper or in the house- to eventually trip. If you have any 110 volt lights they will probably dim when the unit runs. Can you tell if the compressor is cycling on and off as it should?
Randy
WOW i cant believe a ac unit i only tried to use 1 other time is bad lol. Its still like new lol. I cant really tell if its cycling. The air gets cold but it dont run long.
I'm hoping I am wrong, Raider. But sometimes not using an AC very much is worse than using them often. Things have a way of going bad when they sit idle. But don't panic yet as it could be something else causing the problem. I'm just trying to get the most common problems accounted for. The amp test will tell for sure!
Randy
Well i have no one to test the amps for me.
I thought so, because not everyone has an amp meter. If there is a rental place near you it may be possible to rent one for a short while. Otherwise, an AC serviceman or friend with an amp meter is your only choice. I wish I could suggest an easier solution but it is what it is.
I will check with my go-to-guy and see if there is an alternative method you can use to test the compressor in the meantime. Check back tomorrow!
You might try turning the thermostat down low and see if it makes a difference in the breaker not tripping as quick.
Randy
Ok thanks alot. I am scheduled to take it in monday to get looked at.
RE: roof top carrier ducted rv a/c Unit runs and blows cold air only to the rear outlets. we get no air flow the front outlets where do we start looking. Have already looked in ducts, no obstruction seen.
Turns out it was the capacitor. Got a new one for $39 out the door, installed it yesterday and it works great. Thank you for all your help.
Hi Randy, I posted on here 5 days ago about the fan in my ac running backwards........ I fixed it. Since I told you I would let you know here it is..........When I took the unit up to replace the gasket(it was leaking) I put the unit back down backwards. It was fine the whole time, just facing the wrong direction. Hope you get a smile out of this, I did and so did evry single one of my buddies
Take Care
Jim
Well i ran the ac today and it ran for 15 minutes. When it cycled and tried to start back up it just hummed and tripped the breaker.
Oh and if i catch it while its humming i can turn the thermostat to warm for about 3 minutes then turn it back to cold and it works just fine.
@VBnny--I'm not sure how the ducts are arranged on your RV, VBnny. There has to be a split in the duct system if both front and rear vents are supplied by one unit.
You might look beneath the A/C shroud to see if there is a baffle controlling the flow. In the meantime I will see what I can find out for you.
Thanks,
Randy
Its kind of like shutting off ac then turning it right back on. Its like the compressor has too much pressure and it wont turn over. Sorry trying to explain the best i can.
And i tried you suggestion. I turned down the thermostat to low cool and not as cold. Its running fine. But as soon as i turn it up it trips breaker.
@Kevin--Wonderful news, Kevin! Glad you were able to run down the problem. Thanks for your input and for stopping in! Please drop by again!
Thanks again,
Randy
@JSDiver--LOL, JS! I didn't realize you had removed the unit when you asked me about your problem. Sounds like something I would do, so don't feel to bad!
I have a smile on my face because you solved your problem without having to spend a lot of money. I imagine you are a bit relieved yourself.
Thanks for the smile and for the intriguing, if somewhat confusing, question and stop in agin when you get the chance.
Randy
@Raider--Wow! This sounds more and more like the compressor is at fault, Raider. When the compressor is malfunctioning it pulls excess amps which usually gets worse as the compressor gets hot. I wish I could help you more but checking the amps on the compressor is usually the next step if the fan motor seems to be operating correctly.
Please let me know what you find out if you have to take it in for repairs. Usually, replacing a compressor will cost so much it's better to buy a new rooftop AC.
Thanks for the questions and your input!
Randy
We have a 2004 fleetwood prowler with a Coleman ac that is not working. It turns on, but does not blow. I read similar post trying to troubleshoot the problem. I removed the ceiling cover and tried to spin the fan by hand -- it does not move. What now?
Hello Laura! The fan motor bearings are probably worn and have become stuck. If they have oil ports on the bearings, you may be able to fill them with machine oil and eventually get them to turn freely.
But some of today's RV AC units use sleeve type bearings which cannot be repaired requiring the fan motor to be replaced. Sometimes even these sleeve type bearings can be oiled enough to get them going again.
Otherwise, you may have to replace the fan motor with one such as advertised in the ads in the above article.
Good luck with your repairs and thanks for the question.
Randy Godwin
Randy, couple of things. One is I came home today to find that my power cord to the meter outside was fried on the bottom right post of a thirty amp connector. The owners daughter proceeded to tell me it was my power cord and all i had to do was ask her electrician. Yes as a matter of fact we are in New Jersey, how did you know lol. I don't care what it was. I want to know how to avoid it in the future. Obviously a surge protector. So what does tht have to do with the price of rice in China? I have also noticed that the 12 volt lights will change in intensity sometimes. The air conditioner stays on a lot longer than it used to and seems more like a swamp cooler now. Worked with engineers most of my life and a common sense person but it seems as though there might be some inter mingling. I read all of your postings and understand to clean the coils and other stuff for the cooling. I can't figure outthe power fluctuation but now think it has something to do with the meltdown. Just curious on your thoughts. 2005 Fleetwood Gearbox 34 ft toy hauler. Onan 5500 gold Marquis. The lights fluctuated with the generator running also. Thanks for any insight. I thought I was smart?
Hello James. I've found out I'm never smart enough! LOL! The 12 volt lights dimming or increasing in intensity is likely the power converter recharging the batteries when they get below a certain amount of voltage.
The converter doesn't constantly charge the batteries and will cycle on and off.The power cord may have had something to do with the AC but it may be the unit itself. It's possible your AC has lost a bit of freon over the years and has to run longer to achieve the desired temperature.
If your problem was a power surge it seems like the breaker would have tripped before melting the plug. Might just be a bad receptacle.
Sorry I can't be more helpful with your problems!
Randy
Hi. Last season we couldn't get our fan to spin on our Coleman Mack unless we did it manually. So we were told to replace the motor capacitors, one 7.5 MFD and the other is 45 MFD, both 370VAC, Oval. Now that we did the cooling compressor won't kick on to cool the unit. It worked last year even when we had to manually spin the fan, any suggestions?
I would try putting the old compressor capacitor back in to see if the new one is any good, Scott. If the compressor was running last year then the old capacitor was working fine.
It is not unheard of for a new capacitor to be bad. Also, check the connections to the new capacitor to be sure they are making good contact.
Does the compressor seem to try to start at all?
Randy
Randy thanks for responding. I did put the old compressor capacitor back on and tried it but it didn't work. The a/c place had tested it for me and told me it was good so now I have tried both old and new and neither works. It doesn't seem to try to start at all. The guy at the a/c place said it didn't matter how i attached the 3 wires, do you agree with that? also I noticed the compressor seemed really warm while i was trying to test it...
Doesn't sound good, Scott! The only thing left to do is to check to see how many amps the compressor is pulling when trying to start. The start/run amps should be listed on the compressor or on a plate nearby.
Unless you have an amp meter, you will have to either rent one or carry the unit to a serviceman for this check. There should be a wiring diagram indicating the correct capacitor connections if you are concerned with the proper wiring. I hope the compressor is not a goner.
Thanks for your question and please let me know what you found out about your RV AC unit!
Randy
I will do as you recommend and let you know what happens. It amy take a few weeks before I complete this!! Thanks!
Thanks Scott! I will keep my fingers crossed hoping it's not the compressor!
Randy
Hey Randy, GREAT ARTICLE! I've been in my working career, either a salesman for various and sundry things - or an hvac service mechanic.
I actually live in an RV, a Dutchman "Sport" travel trailer. It's just me, and my folk's house is next door - so I've got everything I own and need right around here pretty close.
All good advice, and I couldn't see anything to think otherwise about.
I'm almost ashamed - I'm in Texas, and have had my hands on so many residential and light commercial air conditioning systems that there's no way I'd ever recall even one percent of them. . . .but I have no idea what brand the little package unit is on my trailer! I guess that's because I've not had to ever give it a look though, and that's a good thing!
That is a good thing, WTS! If it ain't broke.....! This article has made me quite a bit of money both in Adsense and Amazon sales, so I suppose it is well received. I sure get lots of questions and comments on it, as well as, a few lucrative AC sales occasionally.
Thanks for the input and wishing you continued good luck with your RV AC.
Randy
Our air conditioner comes on fine, but does not turn off. We have to manually turn the thermostat down. It is either icy or not on. Do we need to replace the thermostat? Thanks.
Hello Charlotte,
The thermostat is probably the culprit in your case, although the fan selector switch or a relay could also be at fault. Replacing the thermostat is a fairly simple job.
Good luck and ask for more info if you need to. Thanks for reading and the question!
Randy Godwin
Hello Randy, we spoke last week and we wanted to tell you what the AC doctor who came out told us about our Coleman Mack. We had replaced both capacitors but then the compressor wouldnt kick on. AC Doc checked it out and said it was pulling 14.1 amps and it should only be pulling 11 so he recommended to replace it with a brand new a/c since he didn't have access to a used one. Also when asked to check the freon he said he is not a licensed freon guy - I always thought if you worked on a/c's you were licensed on it all but guess not. Anyway quick question if it is low/out of freon would that make the compressor not cool and just run hot? Thanks!!
Hello again, Scott! Not everyone who works on A/Cs are licensed to use freon because there are other aspects of the units which do not require recharging the closed freon system.
This is especially true in the case of many roof mounted RV AC units. As for your last question concerning the compressor merely being low on freon-it is possible this is the case, but since the compressor is pulling more amps than required, this indicates a malfunction in the compressor.
I will consult with another AC guy concerning the low freon possibility and post my findings here, hopefully today at some point.
Thanks again for your findings and check back later.
Randy
Thanks again Randy, look forward to your response and thanks for the info on the license too!
Update for Scott! From what I can gather, a low freon charge would not necessarily cause the compressor to draw more amps nor get really hot while in operation.
I know this isn't what you wanted to hear, Scott. But it is what it is. I'm sorry I cannot offer you better news or a better solution to your problem.
Thanks for your questions and comments and good luck with your future repairs. Please feel free to ask for any further info if you think I may be of service.
Randy
Randy thanks so much - at least we now know the correct answer - need a/c has been ordered!! Thanks for all of your information!!!
Take care.
Scott
Enjoy the camping season, Scott! If you need info for installing your new AC then check out this article I wrote especially for the replacement procedure. Thanks!
Randy
I have a 2004 Four Winds travel trailer with a DuoTherm rooftop unit. I'm in Arizona so we use the AC when we're loading up before our trips. I have proper 30 amp shore power at my house so everything runs fine. We went camping this weekend and borrowed a generator in case we needed the AC. The generator is a Yamaha 6600 with a 30amp recep. It was pretty warm so we decided to run the AC. Generator handled it fine but for what ever reason the generator quit running. (I'm guessing due to the altitude in northern Arizona). I got it running again but it was fluctuating all while the AC was running. I finally shut it off concerned with possible damage to the AC. When we got home I plugged it in so we could run the AC while we unloaded. AC cools just fine but it seems the compressor is making a rattling noise. Ran without shutting off for a couple hours so I know it works fine. I'm just curious if there is possible damage to the compressor due to the fluctuation in voltage with the generator. After reading all the previous posts I know I need to check the amp draw (I have an amp meter as I am an electrician). Any ideas or other advice?
Hello Danimal, I'm not sure if there is any damage to your RV AC because of the voltage fluctuation you experienced on your trip. I have a friend who recently had his unit act in a similar manner when he went on a camping trip.
Normally the unit would trip a breaker if it wasn't getting enough amps to run the compressor, but using the generator may have made a difference in this safety precaution.
Sorry I cannot give you any more pertinent info at this time. Checking the amp draw seems to be the only option at this point. An interesting question for this article but with no good answer at this time.
I would like to know the results of your amp test when it is done, if you would be so kind as to notify me.
Thanks for the question and for your time.
Randy Godwin
Thanks for the quick response! I won't be able to check it for a few days as I'm working out of town for the week but I will let you know when I get the chance! Thanks again!
Thanks Danimal! In the meantime I will see if I can find more info for you to consider concerning your problem. Perhaps your findings will assist others with similar RV AC malfunctioning.
Randy
Getting the camper ready for the summer and when I turned the AC on, I could hear the unit start on top but fan dosen't come on. When I climb on top what should I be looking for?
Do you suppose that starting and stopping the generator with the AC on without giving the AC proper amount of time between start/stop could have caused a problem? What happens if you don't give an AC unit an ample amount of time between start/stop?
Thanks
@Lawrence-Try removing the ceiling filter cover to access the squirrel cage type fan. With the unit switched off, give the fan a spin to see if it turns easily. If so, spin the fan hard and switch the unit on to see if the fan starts running on its on.
If it does indeed begin working it is probably a bad fan capacitor.
If the fan doesn't spin easily it is probably because the fan bearings are rusty or stuck. There may be oil tubes expressly for lubricating these bearings on each end of the fan motor. If not, spraying with a good lubricant may buy you more time till you replace the fan motor.
Thanks for the query and good luck with your repairs.
Randy Godwin
@Danimal-In a normal 110 volt plug in situation the breaker would likely trip if the compressor didn't have enough time to recycle between starts. I assume the AC was still plugged into the RV power supply furnished by the generator, so the breaker would have likely still tripped if too many amps were drawn by the compressor.
I also am assuming there were other electrical devices in your RV being powered by the generator too.
Randy
hello i have a 2005 tahoe toy box with a duo therm ac unit. it keeps kicking the breaker in the coach. i had the power checked at the post ,it was 110 volts. i ran it last night and it seemed fine,it cools great,but early in the am it seemed to cycle fairly quickly.like the compresser was starting then stoping. everything lookes clean and i dont see any ice. any help would be great thanks
Hi Mike. This sounds like the freon charge may be a bit low which causes the compressor to recycle frequently. I suggest you get someone to check the run/start amps being drawn by the compressor to see if it is at fault.
If not, having the unit recharged may solve your problem. P;ease let me know what you eventually find out.
Thanks for the query and for your time.
Randy Godwin
Hello, I have a older brisk aire unit. It has worked fine since I bought the rv. I am on my fist camping trip and the AC is giving me trouble. The AC was working fine but all of a sudden the compressor quit. The fan worked though. Then the fan quit but I could here the compressor working. After turning it off for awhile the fan will work and the compressor tries to work but doesn't fully come on. I can see the lights dim in the rv when it tries to come on. I am using a 25 foot 30 amp extension cord.
Hi Alex, this sounds like a bad starting capacitor which operates both fan motor and compressor. Both require an extra boost of energy to get them going and the capacitor is supposed to furnish this to keep from tripping a breaker when both try to start at once.
This is a simple repair job only requiring the removal of the AC shroud to gain access to the capacitor. I hope this is indeed your problem as a capacitor is relatively inexpensive.
Randy
Randy we have a 2007 out back sydney the a/c has always worked fine except for occasions where compressor would make a loud roaring sound kinda like it wouldn't kick which the dealership said was normal for hot days... However lately when ac is running which we only run on auto between 63-68 degrees it's making a rattling noise. What could this be?
Hi Neva, I'm not quite sure about what the the dealer told you as the AC should not make a roaring sound occasionally and sometimes not. Did you buy this RV new?
However, there are several reasons why the unit could make a rattling noise. It's possible there is some debris which may have gotten inside the unit and is obstructing the fan, or else fan may be striking the edge of the cover surrounding it.
The worst possible scenario is the compressor starting to malfunction and the noise is coming from it. This may require removing the shroud-a simple procedure which only requires removing 4 nuts-to discover where the noise is coming from.
I hope it is something simple but it does sound like the compressor may be at fault. Feel free to contact me again when you find the problem and I will attempt to help you further.
Thanks for the question and your time.
Randy Godwin
Thank you soon as this heat wave moves by we will take the shroud off and take a look.. Yes we did buy this camper bran new actaully just a wk after it became available on the dealership lot from factory. The rattling sound has gotten better
@Neva-Great, let me know if you discover the cause of the noise. This has my curiosity aroused. Also, if you have more questions, please feel free to ask here again.
Randy
Randy, will do early in morning before this heat gets very hot we are going to check shroud I cleaned vents today and took flash light looked up looks dusty but that's all.. Noise isn't as bad but it just doesn't feel cool in the camper..had ac on auto 63 and it never kicked on and off but then again it was. Heat index of 100 today by soon as find out will let you know
@Neva-It doesn't sound good at this point, Neva. It could possibly be a low freon charge as this may cause some added noise from the compressor. Let me know what you find out when the shroud is removed.
Randy
Hi Randy,
What a great page! I read the whole thing and I have a new topic for ya... I recently purchased a new to me travel trailer with a ducted Duo-Therm. The guy said to run it on hi when it's hot or it might freeze up. I thought ok, it probably takes Hi to cool this 29' monster so I did. It ran for a couple hours and eventually kicked the breaker. I was in the house when it happened so I didn't hear or notice anything prior to that other than the camper vibrating. My old camper had a 20yr old Coleman that I worked on last year (new capacitor!) but I didn't give the vibration too much thought. Today I took the shroud off and checked the fan blades. The unit is very similar to the old coleman from the top looking down, i.e. one motor with a fan on each end (blower and cooling). With the shroud and cover off, I turned on the fan on high and the whole thing was shaking like a paint mixer. I turned it off. The blades were clean, and the fans rotate freely and the shaft seems firm in the motor. However the blower squirrel cage has one of the little tines about 1/2 missing. I suppose this is the cause of the vibration. There is the big styrofoam block surrounding the blower where the motor mounts. It looks like I may have to take the whole unit off and turn it up-side down to replace the squirrel cage...does that sound right? I can't see any other way it might come out. Please tell me there is an easier way...please :)
Going to click and order some of that cleaner and a fin comb. :)
Hi Greg, and thanks for the compliment you given me concerning this article. I'm glad it's helped a few folks with their RV AC problems.
On some of the Coleman model AC units it is easier to remove the fan motor from the squirrel cage than the SC from the motor. It may be necessary to remove the exhaust fan from the motor shaft first to give you room for withdrawing the shaft from the SC fan.
It may also be necessary to loosen the allen screw from the SC fan to remove it. You get the idea, it depends on the particular model. Some require removal of the metal SC compartment. It should be no major problem. I hope this helps you out and ask for more info if needed.
Thanks for you question, Gregg!
Randy Godwin
I have a 2006 Outback 28RSS. It has a carrier 13.500 AC unit. I bought the rv new and the AC has always cooled perfectly. This past week we went camping and during the day the unit could not keep up and it would reach 84 degrees in the Rv with the outside temp at 92 to 94. The air blowing from the vents was 64 degrees during the day and 55 degrees during the night. The camper would cool to 65 degrees at night but quickly climb back up during the morning. Since I cannot check or add freon what should I do?
Hi David, I would remove the shroud-only 4 retaining nuts in most cases-and check to see if the coils are dirty. This is a common problem with RV AC units which aren't cooling as well as they should.
Use a good coil cleaner such as found on this page if they appear to need cleaning. These coils not only allow the cold air to be transferred to the RV interior, but allow the hot air to be dispelled from the rooftop AC unit.
I hope this fixes your RV AC problem and that you enjoy the next camping trip. Thanks for reading and good luck on your repairs.
Randy Godwin
Cleaned the coils. Minorly dirty, not very. They look shiney and clean now with zero dirt. Outside temp now at 79 degrees with 87% humidity. Overcast with no direct sun. A/C was on all night long and temp inside rv was 65degrees when I checked it at 7:30 a.m. With air off while I cleaned coils the inside air went to 79 degrees and after turning it back on it has dropped to 75 degrees while blowing 54 degrees from the vents. My buddy has the exact same rv as me and his blows at 44 degrees from vents. Never checked mine until it started not cooling as well this week so I don't know how cold it blew before. I would expect that it should be the same as his since they are identical rv's with the exact same a/c.
@David-44 degrees sounds about right. You probably have a very small freon leak which has eventually caused the system to be low enough to affect the cooling process.
Recharging the system may be the only option for you, David. Although it is not a difficult process, I hesitate to suggest you do it yourself. At any rate, it would cost less than replacing the unit.
Sorry I cannot be of more help to you. Good luck and thanks for your input and questions.
Randy
I have a 1997 gulf stream seahawk with a 15,000 btu coleman. The only way to shut the compessor of is to turn off breaker. You can put thermostat in any position and ac compressor will still run. Was 90 in camper yesterday and ac was putting out 59 degree air. Unit will eventually freeze up. do you have any ideas?
Sounds like you need to replace the thermostat, S. Simon. You may access it by removing the ceiling assembly. It's easy to replace and relatively inexpensive. You may find a replacement through the parts links on this page.
Good luck and thanks for the question.
Randy Godwin
The thermostate is located on the wall, I neglected to say it is ducted air system. I remoed rhe thermostat and when I turned the breaker on the compressor still came on
I unplugged power from relay board and plugged it back in and unit started working correctly. Could this have reset the themostat or do u think I should pue\rchase a new relay board
I wondered if the thermostat was on the unit or not, S Simon. I would try it a bit before purchasing a new board. Perhaps the thermostat did indeed reset.
Randy
Hello, i have the same prob. as ( jim 6 weeks ago) acept I have not changed a thing. The fan blows fine alone but as soon as you switch it to one of the cool settings the fan slows to a stop and then starts in the wrong direction. I un hooked the thermostat , and went through all settings and it works properly as long as the compresser is not on.?????? any ideas ,thanks jake
Hello Jake, Why not simply turn the unit around backwards, like Jim did? LOL! Just joking, of course.:)
This may be a problem with the switch, Jake. Or it may be a screwy capacitor which starts the compressor. You really need to do an amp check on the compressor if it doesn't run at all. You didn't mention if the compressor ever started or not.
Perhaps a little more info could help me narrow down the problem.
Randy Godwin
Thanks for the fast reply. Yes the compressor seems to work as it should ( cools to 50 or so )In fact every thing seems to be fine .Just cant figure out why the blower switches direction when the compressor is running. thanks ,jake
That is a puzzler, Jake. Since the fan is running backwards, it would mean the air blowing through the coils would be reversed also and not cool properly. Does this unit have 1 or 2 capacitors?
Randy
2, one little and one bigger.
Got it , new capacitor and good as new. Thanks for your time.
Sorry to take so long responding, Jake. I'm on vacation in Jamaica and just checked my comments.
Glad you found the problem and thanks for your question and the solution as it may help other RV owners with similar problems.
Thanks again for visiting my articles.
Randy
Hi Randy. Hoping you can help me out with our problem. Our camper is an older Coachmen, probably a '74 or so. Went camping earlier this week and while camping and running the ac, we lost all power, tripped a breaker. Turned the breaker back on and ran find for 2 days. On our last night there, in the middle of the night, we lost all power to the ac unit. Lights and tv, etc. all still work, but when you go to turn the ac on, it's like there is no power to it at all. We've checked the breakers and it's not that. We've switched outlets that the extension cord is plugged into but that didn't help. Checked the fan, it moves freely. Don't know what else to do. If you could point us in any direction, we would be grateful, thank you.
Rushell, you may have an A/C unit with only one starting capacitor for both fan motor and compressor. This sounds like your problem. Check this first before going any further as this is a common problem.
Randy Godwin
Randy I have a 1984 Allegro MH. When I run the 2 A/C units
(Duo therm) from the generator they both work find. When I am parked and run and A/C from the house or RV parks only the front unit works. Checking A/C at the rear units and find none, Is this correct from manufacture?. It has been this way sense I have owned it, 1992.
Hello Del, I assume the home and RV park hook ups are 50 amp rated and not the standard 30 amp campsite outlets.
The reason I ask is 2 units will probably pull more amperage than a standard home or RV campsite hook up.
Otherwise, it sounds as if you have 2 different line connections for the land and generator operations. Can you give me more info?
Randy
Hello Randy, I'm diagnosing my coleman Mach RV A/C unit.
Problem #1: Firstly, I'm pretty sure I have a thermostat problem. It is inconsistent at putting 12Vdc on yellow when I switch it to cool. I can handle that one.
Problem #2: In the ceiling unit's control box, I have no evidence of the compressor relay switching. Even when I jumper 12V to the yellow wire and verify it is present at the control board level, the 110Vac is not passing through the compressor relay to the purple wire.
Problem #3: I installed a switch (service & troubleshooting use only) in place of the control unit's compressor relay. The compressor will start & run, but it the evap will not cool down. I have shop-vac'd the evap coil and during my testing, I have my hand right on the evap coil when the compressor's running. I can not discern any change in temp. This is the issue I am most concerned with. In my mind this is a ref charge issue; likely no charge. Thoughts, ideas?
You are probably right, Mike. It sounds as if you need to recharge the unit as everything else seems normal. The relay is likely pressure activated and this also indicates low freon charge.
I hope the recharge gets you going again and thanks for the detailed description of your troubleshooting steps.
Randy
From above: blower replacement.
Well I replaced the blower and both squirel cage and exhaust fan blades. Only when I picked up the original exhause blade did I notice the large mass of mud-dobber nest on the hub of the blade!! I had checked the blades themselves, but did not reach behind to feel what I couldn't see was about a fistful of dried mud. This mass makes way more sense in throwing the motor off balance than a small piece of plastic missing from the SQ blade. I was irritated to say the least. The good part though is that the new motor spins smooth and quiet. And with the exhaust blade out of the way, I was able to give the coils a good cleaning. Maybe someone's future internet search for vibrating blower fan will point to this post and remind them to feel behind the blade where you can't see for mud dobbers :)
Peace!
Gregg
Gregg, sorry you didn't find the mud dobber nest before going to all the trouble of replacing the fans. But I will certainly suggest this possibility to any future similar problems an RV owner may have.
Thanks for relating your experience and the solution to your problem. I'm sure it will help others in the future.
Randy
Sorry about the misspelled words,I'm posting this with my new,first, smart phone and it "corrects" my spelling. We "purchased" the camper.
Dennis
What should the low side freon presure be on a duro thurm brisk air ac.
@Danny-This should be listed on the compressor or on a plate on the AC itself. The pressure will vary depending on how the unit is cycling and will be the same on both high and low sides when the unit has been turned off for awhile.
For a more concise reading you will have to consult a manual for your unit. I do not have this info at hand.
Randy
Thanks Randy it is working ok now. It was run without a filter so I had to clean the coils and I added three ounces of freon.
Great Danny! Dirty coils are a common RV AC problem. Enjoy a nice cool camping trip now. Thanks for your input and questions.
Randy
Randy, We just purchased a 2003 Gulf Stream Innsbruck camper. When the air conditioner is set past about the half way point on the coolness knob there is a large load put on the curcuit for about 1 to 2 seconds about 15 seconds into the non-compressor portion of the cycle. On "high cool" and the coldest setting, the compressor runs about 90 seconds and than shuts off for about 60 second during which the high load happens. I haven't put an amp meter on it yet but it is enough to make a 4000watt/5000starting generator about jump out of my pickup than die when it happens. I put a 6500watt generator on it and it heavily loads it but it doesn't kill it. You can also tell there is the same high load put on it when the camper is plugged into 110v. Is it a capacitor loading or what? Any ideas?
Dennis
Dennis, if you check the capacitor ohms with a multimeter you should get a descending, random number if the capacitor is good. In other words-198-197-196 the longer the leads are attached. The numbers are important to the test as long as they descend in value.
The amp meter should tell the tale on the compressor if the capacitors are good.
Randy
Randy
Hi Randy, we recently had one of our A/C's replaced in our '96 Newmar Mountain Aire. Since then we've been doing some long term camping in Texas and Florida and the electric costs have been astronomical! $245/month! Anyway, the only thing I could think of checking was to see if the installers might have inadvertently re-wired the units to 110 rather than 220. So, I checked the breakers and had the proper amperage (13+ on rear and 14+ on front), but each was all on just one leg of the 220 circuit. The other leg of each circuit was essentially zero. Is this normal? I thought that with 220 I'd read amperage off each of the two wires for the circuit.
Hello Steve. Are you positive your RV operates on 220 volts? Most RV AC rooftop units operate on 110 volts. If you have a 220 volt hookup-probably at least 50 amps- it would indeed seem as if they would operate on separate legs of the 220 volt supply. But one thermostat might require the same power supply for both.
Randy
The RV is the typical 50 amp service. The circuit breaker for each A/C has two wires and the (single) breaker is the type that has two switches on it; one red and one blue. In other words, each A/C has two wires, which, I assume is for two 120v wires. Given this, I'm pretty sure that, although the coach has 120 supply, it is split as needed inside. Now I'm going to see if I can find the manual to verify! Oh yeah, there is a single thermostat for both zones. It's a central type system.
Randy - It just dawned on me that the second wire is likely for the heat strips. I doubt that the compressor and heat strip run off the same wire. Whatdayathink?
Apparently the AC system uses one leg of the 220 volt service to supply the entire cooling system, Steve. The single thermostat would likely require a single 110 volt circuit for activating both units.
I believe your units are installed correctly. Thanks for the question and for reading my articles.
Randy
@Steve-Not sure about the heat strips in your system. Most rooftop AC units I've dealt with use the same circuit to operate both AC and heat strips since they do not pull amps at the same time. You could be correct though.
Randy
Thank you for your info. Nice web page. It has been a nice way to get information.
Always glad to hear my articles have worth, Steve. Please check out my other RV repair articles if you ever need them.
Thanks again for stopping by.
Randy
I have a duo therm that does not blow cold. Investigation revealed a broken copper tube that routes from the compressor to the cooling fins. Line severed vertically about a 1/2" from 1st cooling fin. Is there a way to re-couple the line? and then have someone charge the system? or is it replace time ?
Bruce G
Hi Bruce. Yes, the line may be repaired and the unit recharged if the broken line is the only problem. Check with an AC repair service or an RV dealer. Thanks for stopping by and good luck on the repairs!
Randy
MI rooftop A/C unit is freezing up. After a while it stops blowing cold. When I go up on top and look in the vents there is a coating of ice on all the tubes. Ideas?
Hi Mike. There are several things which will cause the coils to freeze over in a rooftop RV AC unit. The most common cause is running the thermostat too high in hot humid weather.
Also, if the coils are really dirty, the air cannot pass through the fins easily and transfer the cold to the air intended for cooling your RV.
Usually a good cleaning of the coils will remedy this problem. Use a good coil cleaner, such as found in the ads on this page, and this should solve your problem.
The most serious problem which may cause your unit to ice up is a low freon charge. Just before an ac unit runs out of freon it will get really cold and cause the icing. If the other remedies do not work, a recharge is in order. In this case, you have a leak somewhere in the system.
I hope this info helps you find the problem. Thanks for the question and for reading my articles.
Randy Godwin
Can the line repair be a DIY I am pretty good at these things, but would need a direction as to soldering a union or utilize a threaded coupling or . . . .
Thank you
@Bruce-Yes it can, Bruce. Depending on where the line is broken, a copper coupling may be used to repair the line for recharging.
A vacuum must be pulled on the unit before recharging and a piercing valve used to enable recharging the unit with freon. Pulling the vacuum will also tell whether there are any more leaks in the system which need repairing.
Good luck and I hope you have no problem with the repairs.
Randy
I have a travel trailer that has a rooftop air conditioner. About a week ago it quit cooling. The air conditoner runs but it blows hot air. What could be the problem?
Hello AE. First you must see if the compressor is working. If so, the system may be low on freon. If not, it is probably a bad starting capacitor or at worst, a bad compressor. Let me know what you find for further advice.
Randy Godwin
my ac unit blows cold air at night but as soon as the suns starts to rise it dosent cool very well. trying to repair it myself what do u think the prob is. thanks
I was usning my Dometic Heat Pump in the a/c mode when my son inadvertantly pushed a camping chair into the breaker switch that controls the a/c unit. Of course the unti immediately shut down. I can't get it to come back on. In laymans terms I think I blew a fuse. Is that a possibility or did something more drastic happen?
thanks. My email address is terrence.wright@kcc.usda.gov
Hi James! I would try giving both coils a good thorough cleaning to see if restricted airflow through them may be causing your problems. Otherwise, your unit may be low on freon and needs recharging.
Feel free to ask for more info if needed and thanks for dropping in and reading my articles.
Randy Godwin
Hello Terry, unless you can check the breaker switch with a multimeter there is no way to see if the breaker itself is the culprit.
You may also see if power is getting to the breaker switch itself using the same tester or multimeter. It isn't uncommon for these breakers to malfunction. Be sure to check the on board breakers in the 110 volt AC panel box to insure the A/C breaker there is not tripped also.
Ask for more info if needed and thanks for reading my articles.
Randy Godwin
Randy, Great Ideas. I am new to this type of thing so my question is: I have a 1989 Mobil Villa & was wondering if the freon used on most trailers was R-12 or R-22? I am a certified auto tech, but this is my 1st travel trailer. Thanks.
I'm really not sure about the type of freon used on your particular model RV AC, Big E Fan. It should be marked appropriately somewhere on the unit itself. I would thin it would be R-22, but this is just a guess on my part.
Thanks for the question and I will see if I can find further info for you.
Randy
Thanks Randy, I thought it may be 22 but wasn't sure. I will look when I get my rv back home (is stored @ a friends house for now).
No problem, Big E Fan. You should find the freon type listed on the unit. Thanks for stopping by.
Randy
OUR 2 RV A/C WILL COME ON BY THEMSELVES WHEN THEY ARE NOT IN THE ON POSITIONS. THE COMPRESSOR WILL SUDDENLY COME ON WHEN THE AC IS IN THE OFF POSITION. OR THE FAN WILL COME ON WITH THE FAN IN THE OFF POSTION.
TO KEEP THE AC FROM COMING ON WE HAVE TO DISCONNECT THE ELECTRIC SUPPLY.
DO WE HAVE A THERMOSTAT OR A 12 VOLT RELAY PROBLEM?
Hi David! It does indeed sound like you have a thermostat problem since both units are affected. It could be a relay problem only if both A/C units are controlled with one relay which is not normally the case.
I would try a new thermostat first or check the present one with a multimeter to see if there is voltage going to the units with the switch in the cool or fan positions.
I'd like to hear what you find out when you isolate the problem. Thanks for the questions and for checking out my article.
Randy Godwin
Wondering if anyone knows of a wall thermostat I could use with my Coleman Mach unit that will allow for a remote sensor and has auto heat/cool. All I can find are residental wall thermostats that operate on 24v and I obviously need a 12v. I have been able to use a regular Honeywell wall thermostat that is millivolt to 24v and that works, BUT I can't attach a remote thermostat (really important) nor does it have an auto heat/cool capacity.
thanks for ANY assistance!!!
Holly, is your Mach already equipped to be changed to a remote? It makes a difference, you know!
Randy
Hi Randy
My Mach is set up for a wall thermostat, I have had a regular household "Filtrete" brand thermostat on there and has worked fine for both heating and cooling for the last 8 months (I have to manually change from heat to cool with this unit, I have a heat strip on my Mach) Let me give the reason I am looking for a remote sensor/thermostat.(wired remote is fine) The Mach is mounted on the top of an insulated cargo container that is being used as a growing room for animal fodder, think an enclosed greenhouse.(completly legal! LOL growing barley seed) There is LOTS of moisture, and the reason that the Filtrete wall thermostat needs to be replaced, is that it was constantly getting wet! duh! and has now stopped working. So, I want to be able to get a thermostat that has a remote (waterproof!) sensor I can mount on the inside of the unit, and mount the the actual thermostat control through the wall of the container on the outside, where it is dry. I can find thermostats that are 24v that can have a remote sensor attached, and are automatic heat/cool )but I can't find anything like that that operates on a 12v, or a millivolt to 24v system. Even one that isn't an auto changeover to heat and cool, as long as it can have a remote sensor attached.
So, does that help a bit?
Sorry Holly, I was half asleep when i responded to your previous post. Yes, I understand what you are trying to do and indeed the thermostat itself only has to have a remote operated sensor.
I'll look around for more info on this option!
Randy
Thanks Randy! I REALLY appreciate any assistance you can give me to find something that will work! :)
Hi Randy,
Any luck finding a 12V or millivolt to 24V thermostat that can take a remote (waterproof) sensor?
Sorry Holly, check with the maker of your particular RV AC as I don't have any special access to these manufacturers.
I will check further, though!
WOAH!!!!!!!!!!!! This thang here still gets some good looking over!
Seems obvious now (having looked at the previous comment I left) that the danged old a/c on this little home of mine is a Coleman.
I haven't messed with it much other than washing the indoor coil with some super duper alkaline coil cleaner....but the other day I ran the a/c a little bit.
Pretty mild Winter over here!
I think I've either got a wire loose or a burnt winding...thing ran in low and high (the fan) but not the speed in the middle!!!
Yo, Wesman! A very mild winter here in southern GA too! Some have already been cutting their lawns the last few weeks or so as not much frost has burned the grass this year.
Sounds like you've got a bad fan switch in your AC or else a bad relay in the fan motor, Wesman! Thanks for stopping by!
SSSSS
I'd like it to be the switch!
I never really used "medium" anyway.
I know one thing....my tstat is about gone. It's about to where it's just calling for a/c or it ain't, and all that space in between is nothing but dead space.
Probably I'm going to have to get me a replacement part OEM style or a good universal one.
More than likely it is the switch, Wesman. An easy and not too expensive fix for you. Yep, sounds like you are overdue for a new thermostat too! Better get ready for the hot stuff!
SSSSS
I have a 1987 Executive RV. It has the Dometic under floor split system A/C unites 3,500 BTU 125v 14 amps running. The evap runs on the 12v, condenser 125v.. The front unit runs off the Gen. or the power cord. The rear unit which was fine when last operated will not start up now. Not trying to run both at the same time. You can hear the Gen pull down each time the unit attempts to start. I can hear what I think is the power relay clicking (strongly) when you demand cooling. However the unit will not start. A idea's? Thanks
PS: Sorry, I left out one piece of info. The indoor 12v runs the evap fan and the 125 volt condenser fan run when cooling is demanded.
Hello Doyle! Sorry to take so long to answer your question, but a man has to go fishing sometimes! LOL! Have checked the fan to see if it will turn freely if spun by hand? Often these fans have sleeves instead of ball bearings and they tend to stick if not used in a while.
If the compressor is bad it will pull more amps than what is listed on the label. Check the start/run amps to see if it is pulling more than required. If I have misunderstood your question, or you need more info, then please feel free to ask.
Randy
Hi Randy,
I experienced a power surge on my duotherm hp 59516.331 roof top rv ac on 1998 cardinal 5th wheel. The ac was running fine before the surge. Now the ac will not do anything. the heat side on the manual wall mounted tstat works fine. I replaced the hard start capacitor. Still no change
Yo Noel! Perhaps the surge may have damaged a relay on your unit. You mentioned the heat side of the wall mount thermostat working but didn't say if the A/C used the same thermostat or if your unit is a combination heat/cool unit. If so, it's possible the thermostat may be faulty on the A/C side. Check the voltage on this side to see if it is sending current to the unit. If so, you may have to check at the other end--in the ceiling assembly possibly-to see if a relay is at fault.
If I'm not understanding your unit correctly, then feel free to ask for more info.
Yo Randy,
Thanks for the information! To be clear the ac and heat use the same single mount Duotherm manual thermostat. The gas heat unit is located underneath the kitchen counter next to the hot water heater and is working fine. Will that relay in ceiling assembly be part of the control circuit board?
Thanks Again
Noel
Okay Noel, I wondered if the A/C unit also had a heat strip, but now I understand you have two separate heat and cool sources. Still, the thermostat may be at fault so you might check the voltage supposed to be going to the AC unit when the thermostat for the cool side clicks on.
You may have an 18 volt charge but I'm not sure of the thermostat in your RV. If this checks out fine you must find where the thermostat wires end up in the AC unit itself. Not sure on your model but you may be able to find a wiring diagram online.
Using a multimeter, you should be able to tell where the current from the thermostat goes to and therefore what the problem is. I hope this helps you a bit more but check back if necessary.
Randy
Randy, I have a 2007 Outback with a 15,000 BTU Carrier A/C I have noticed that the noise level of the unit has increased over the years and recently the start ups have been really noisy. I can sometimes bump the unit from below and the noise subsides and it seems that the longer it runs the noise eventually decreases. any suggestions would be appreciated. thanks.
Hey Jimmy Mac! It's possible the shock absorbers on the compressor may be worn or even loose on your unit or perhaps there is something which is making the fan be out of balance such as a mud dobber nest stuck to the fan blade. I've seen this happen several times before.
I would suggest removing the cowling from the unit and checking for such obstructions or loose rubber shock absorbers on the compressor. It may be necessary to watch the unit while someone else starts it up to observe the noise problem.
Feel free to ask for more info if this advice doesn't help. Sometimes the compressor will make noise when it first starts up if it is very old or beginning to go bad. Thanks for your question and for checking out my articles.
Randy
Hi, I have a Coleman model 8333-876 rooftop on my 5th wheel, The Compressor won't run at all. The fan will run but... it runs slow on "fast" and fast on "slow"!I replaced the fan, hard start, and run caps on the unit. I hear no relay click, or and sign of a compressor hum/noise. The only thing that works is the fan although it runs different/backwards of the fan settings on the wall thermostat!!!No one has changed any wires, or worked on the unit. It ran good about a week ago. any ideas? Thanks.....
hello Ron! Have you checked the thermostat to see if it is operating correctly? You didn't indicate whether or not the thermostat also controlled the furnace in your RV, but for now I'll assume it does.
It seems you've eliminated almost everything else which could cause the problem, so checking the voltage going from the thermostat to the rooftop AC would be the next logical step. In fact, you may have gone to a lot of unnecessary trouble and expense already, but we aren't sure of that yet.
Since I'm not sure what type of thermostat is in your RV I can't tell you what the multimeter should read as far as voltage is concerned. This info should be listed somewhere on the thermostat itself.
It is possible there are 2 separate control features on the thermostat with the AC side being inoperable. It may not be sending the correct signal to the compressor to start up or run. I would check this out before doing anything else. A new thermostat is usually very inexpensive and quite easy to replace if you find it is the culprit.
This is only a suggestion so feel free to ask for more info if needed. Thanks for the question and please let me know if my suggestions helped or not. Thanks again for checking out my RV repair articles. Good luck on your repairs!
Randy Godwin
Hi Randy,
I have a stock coleman rv thermostat that came with the unit. It is a heat cool type that runs both the rooftop and furnace. It has heat/ cool, fan auto, and high and low fan speeds. I checked the fuse in it... but I wasnt lucky, its good! I suspect the thermostat but at 80 dollars I wanted to be sure before replacing that also!It worked great about a week ago, now for some reason the fan hi, and low setting are reversed! and the compressor will not hum, click, buzz... just sorta sets there laughing at me. I thought maybe a wire burned off the compressor but they are all solid and good...only thing that works is the fan. well kinda, the setting for high and low are working backwards. I was wondering how to check the relays in the metal box located in the plenum. Thank you for such a fast response!
I doubt seriously the compressor is at fault, Ron. And you know it isn't the fan if you've replaced it. You should be able to check the thermostat wires where they enter the unit to see if voltage is present. The relay should be nearby also. You can also check the voltage at the thermostat itself where the wire leads to the A/C. Not sure what voltage is required for normal operation on your unit.
But if you fail to get voltage, it is probably the thermostat,. No, or low voltage, and a relay is more than likely the culprit. Sorry I can't be of more assistance at this time, but I don't have a schematic for your unit. You can perhaps find one online if you need to know the location of the relays. Please check back if you think I can help you further.
Randy
my a/c worked fine last yr. this yr. took it out, turned on the a/c and it started vibrating the whole camper and was very loud. can you tell me what it could be. thanks.
oh yea thought I better tell you its a 1999 coachman
Hi Karen! The most common problem when an A/C starts vibrating after being idle for awhile is when a mud dauber builds a nest on one of the air conditioner fan blades. This throws the motor out of balance and creates the vibrations you are describing.
The only other cause in most cases is from a bad compressor or either bad bearings in the fan motor, But check out the fan blades on both the squirrel cage type fan and the regular bladed fan on either ends of the fan motor shaft for nests first.
You didn't mention whether the unit was cooling or not. Ask for more info if needed.
Thanks for the question and for reading!
Randy
Thanks Randy: We are going to check the a/c out today. And for the cooling, it does blow air out, but didn't leave it on long enough to see because was to scared to leave it on to long with it making that noise. Was scared it would really mess things up. I'm hoping its mud daubers.
I am too, Karen. Once you remove the cowling from the unit you may switch it on for a short time and hopefully see what is vibrating in the unit. It is also possible the compressor's rubber shock absorbers may be deteriorated and are allowing it to shake while running.
Please tell me what you find out so I may help others with a similar problem. A word of advice, though! It is often difficult to see inside the squirrel cage fan--this one blows air into the RV--to detect a mud dauber nest or other object.
If this is the case--hopefully--clean the nest out thoroughly because the slightest weight will create an imbalance and therefore vibrations in the unit.
Thanks again I'm keeping my fingers crossed for your success.
Randy
Well Randy you were right. It was a mud daubers nest: Works like a charm. Thanks again for all your help.
I love it when a plan comes together, Karen! LOL! Thanks for coming back and letting me know what the problem was. I also have repair articles on almost any other RV problem you may encounter, so next time you have a problem please check out those too! Have a great camping season!
Randy SSSSS
If I have anymore problems you will be the first I will contact. And for camping season love it. Thanks again
I'd really appreciate it, Karen. Glad to be of service!
Randy
my furnace or ac unit is not workin.. I have no power to the high voltage caps that are on the roof. I also do not have the 12v power to the termostat. all fuses are good and there are not breakers tripped. I have the 110vac to the control circuit board that is on the inside of the ac unit.. If i bypass the 110volt relay on the board i can get it to turn on.. does the 12v from the thermstate come from this board? what do u think
Yes, if the thermostat is bad, or is not being furnished power by the converter, the unit will not run. This is probably your problem. Are all of the other 12 volt DC items working properly? If so, the thermostat is likely the culprit.
Ask for more info if needed!
Randy SSSSS
Hey Randy: I have another problem, which I noticed last yr. when ever the a/c is running and even goes off water runs threw the return vent and the vents. There is no drain hose that we can see. Can you help me.
Hello again, Karen! This is a common problem when the coils get dirty or almost stopped up with some type of debris or simply dirt collected over the years.
There some older units with drains which may get clogged, but most new ones simply disperse the moisture into the air in a fine spray.
There are coil cleaners especially for this task sold on this page, but you might get by using some 409 or similar such household cleaner if you wet the coils and soak them for a bit.
This job is rather messy so it is important to protect the top of your RV from the gunk removed by quickly washing the spills away with a water hose or spray. A wet/dry vacuum is really a good thing to have for this maintenance job. Be sure to disconnect the unit from the elec. power, or turn the breaker off until the unit is dry to prevent damage to it or yourself.
I'll bet your unit stops leaking if you clean both coils well. I know your unit will cool much better without working so hard too!
Thanks for the question and ask again for more info.
Randy
Hey Randy: My husband states that he cleaned them real good when we had the problem with the mud daubers.
Well, it appears you DO have a drain in your unit then, Karen. If both the front and rear coils are clean, then I can see no other reason for moisture to be leaking down through the vents unless the gasket is bad between the unit and the roof.
If debris or dirt is layering the inside bottom of the unit the drain may not be visible. Let me know what you find out of ask for more info if needed.
bill 2 years ago
my 2000 honda generator will start up my ac unit fine and run well on the initial start-up period. but, once the thermostat kicks the compressor off and the trailer warms so the compressor will have to kick back on, this is when the geenerator will not kick the compressor on again and will trip the breaker. it's an old 88 featherlite camper with and old air conditioner. is ther anything that will assist the compressor once it tries to restart???