RV Air Conditioner Troubleshooting Tips And Maintenance Guide
If properly maintained, the RV air conditioner units, rooftop or not in travel trailers or any kind of RV, will provide you several years of cooling efficiency.
This article is divided into two segments or parts:
- The first segment discusses the process of troubleshooting your RV air conditioner unit and deciding on the parts to service or replace,
- The second part of the article is about maintaining your RV AC unit and also decide on the purchasing of spare parts and having a planned maintenance schedule of the unit.
These maintenance and repair tips are easy to follow, whether or not you have practical experience.
Background Information on the Workings of an AC
If you are not familiar with the workings of a motorhome air conditioning, this article will show you the parts to service, check and repair.
Just to begin, an introduction. An RV air conditioner is made up of a compressor – for circulating cooling fluids such as Freon through the fins and coils of its condenser – and the fan. The fan is responsible for blowing cooled air across the RV.
The compressor and fan are controlled by a thermostat. They are also kickstarted by the capacitors. The 12-volt electrical system is used to run the AC thermostat and other similar controls.
Where to Start
The vast majority of the RV air conditioner issues are caused because the users do not change filters, do not lubricate bearings, and do not clean coils.
With that said, I am sure that many problems faced by air conditioners – like going off prematurely or sluggish behavior can be fixed by checking the electrical system. The problems are often not as complicated as we think, which is why it is advisable to start with the most straightforward possibilities. And if the problem persists, you can carry out further investigation to decide on whether to replace items like compressor and fan or to just get a new air conditioner.
We have decided to start by addressing the basic electrical issues.
RV Air Conditioner: Electrical Issues
Make sure the electrical supply to your unit is switched off before attempting to carry out any repair or maintenance on your rooftop AC unit. You either trip the AC breaker or unplug the unit from its electrical receptacle.
Part 1: Troubleshooting Of The RV Air Conditioner
Common RV AC Issues that You Can Troubleshoot on Your Own
- If you notice any unusual noise from your AC or it stops working, check to be sure the controls and units are getting adequate power.
- If you notice that your AC compressor or fan has stopped blowing air, is slow to start, blows warm air, blows weakly, trips your breaker, stops working after a while or dims your light, check the capacitors and have them replaced if necessary.
- If it is not blowing air, check your fan capacitor and the compressor capacitor if it is not cooling.
- If there is nothing wrong with the capacitor, crosscheck to ensure that power is actually being transmitted to the thermostat by checking if the 12-volt appliances are functioning.
- Check the thermostat function if wall-mounted. And if the unit only works when the thermostat wires are connected, it means that there is a problem with the thermostat. A thermostat is pretty easy to replace.
- If the thermostat and capacitor are in good condition, the defect may be with the control board.
- If there is nothing wrong with the control board, you may need to change the compressor or fan motor.
- The fan motor is probably bad if the fan can only work at a specific speed.
- You can choose to rebuild the fan motor. Or you can have the fan motor replaced if you feel the unit is otherwise in good shape.
- A compressor that malfunctions should be replaced, not repaired.
- If your system overheats or drips, it could mean your coils need to be cleaned.
- A leaking AC might mean that the gasket is leaking or the bolts are loose.
- If ice builds up in the system or it becomes very cold, it may mean the system is low on Freon.
- If you notice that your unit is noisy, it could be that something is interfering with the motors; this can be checked by getting rid of the shroud.
- Overheating can be caused by dirty coils. Clean coils can release excessive heat into the air.
- If you notice water leaking into from your AC, check it out to know the origin of the water. The leak may be from the gasket located between the roof and the unit; if this is the case, it is actually easy to fix. Carefully tighten the bolts, and if that fails, have the gasket replaced.
- The dripping from the unit may be due to the presence of condensed water in the wrong location (usually the pan located underneath the air conditioner) where the fan cannot evaporate it. This type of water buildup can be attributed to dirty coils and can be fixed by having the coils cleaned.
- If your unit is producing very cold air, building ice or even stops cooling completely, it may mean the unit is low on Freon. Visible oily residues can be seen around the Freon leak occasionally. You can use a self-piercing valve to attach the Freon to the system.
- You can fix a noisy motor by removing the shroud i.e. cover of your roof AC unit, to see if everything is where it ought to be. The rubber shock absorber located on the fan and compressor may be the ones interfering with the motion.
Is Your Unit Receiving Adequate Power Supply?
A unit that fails to react as expected – i.e. making noise or coming on, might not be getting adequate power supply. Check the 12-volt panel to see if the fuse is still intact and that the breaker is still intact. The AC controls and the thermostat are run by a 12-volt power system.
AC units require very high voltage power and might be more than what a 15-amp power pole is capable of handling. So if you have two modern RV AC rooftop units, the units may end up drawing more power than the 30-amp power at the campground can handle.
Likewise, if the power drawn by the RV AC unit is more than what the system can handle, the fuse or breaker will shut down. Fortunately, most RV parks and campgrounds today come equipped with the 50-amp service required by modern multi-unit air conditioners.
Like the vent fans and lights in your motor home, 12-volt power is used to power the thermostat. And if any of these accessories is not functioning, then it means something is wrong with your 12-volt power. The power converter responsible for converting the high-voltage power to a 12-volt power might be bad.
Check Your Capacitors
The capacitor is used to store electricity to provide the compressor and fan motor with some much-needed boost while the RV AC unit is working. It is easy for a capacitor to become worse if the RV unit has been left unused for some time and is unable to offer that little push needed to give life to the motors. A bad capacitor can explode in a cloud of smoke without causing any damage to the unit.
If your compressor or fan fails to start, the starting capacitor might be malfunctioning. There are several symptoms of a bad capacitor: the unit hums while trying to start, it runs for a little while before it trips a breaker, while the fan requires a little push to start, or the bad compressor causes hot air to blow.
Capacitors are shaped like small batteries, buttons or flasks. You can use a multimeter to test your capacitor. A random value that decreases as the probe remains in place should appear on the thermometer of a good capacitor.
It is easy to replace a bad capacitor. When you want to order a new one, make sure you check the model numbers and required voltage of the old capacitor.
Be sure to put off the power when you want to replace it. Pay attention to where each wire goes, so you can use this information to install the newly purchased one in the exact same way. Do not use your bare hands to touch the terminals. Before you dismiss the old capacitor, make sure you use a screwdriver to connect its terminals (be sure to use an insulated screwdriver) to drain out the electrical charge.
Most AC units function well after their capacitor is replaced.
Crosscheck the Switches and Thermostat
A bad thermostat can also cause problems for your unit. You can use your multimeter to check the voltage of your thermostat if it is wall-mounted. If you notice that the only time the unit comes on is when the thermostat wires are touching each other, it means the thermostat is bad.
If your AC stops working and the capacitors and the thermostat are both okay, then the problem might be with the control board.
You can order new parts for your switches and thermostats online after locating the appropriate serial numbers and model. In most cases, these items are easily replaceable.
Do not forget to pay close attention to the wiring connections when you are replacing your electrical components.
The Checks In The Compressor And The Fan?
If after performing the electrical checks described above, your RV air conditioner keeps blowing at limited speed or refuses to blow air, it may represent that something is wrong with your fan motor. Sometimes, compressors and fans leak oil when they are under malfunction.
A functioning compressor should be warm to the touch and audible when turned on. You can use a clamp-on ammeter to test your compressor, a device that I recommend you to buy. Check the number of amps drawn by the compressor. If you notice that it is drawing more current than the required amp rating for the unit, the compressor is malfunctioning.
Replacing and Removing your AC Fan Motor
Oiling the fan motor is a great way to get it to run better. If after oiling, the fan motor of your AC is still slow to start, or requires a nudge to start, does not run at all, or runs at a certain speed, you might need to replace or rebuild it.
Don’t just use any oil for this; you can read the manual of the manufacturer of the RV air conditioner for advice about the most suitable oil. However, you need to be careful when buying oil for your fan, a cheap one can cause long term damage to your unit.
There are two types of fan motors: the ones with exposed bearings that are easy to lubricate and the ones with sleeved bearings. The first can be rebuilt cheaply and can last for years. However, the same cannot be said for the sleeved-bearing ones.
Sleeves fan motor, unlike bearings fan motors, cannot be rebuilt economically, so you will have to replace it with another one if it spoils.
If other aspects of your AC unit appear to be in good shape, you can get a new fan motor for your unit. Just change the motor, as in those cases, there is no need to change anything else.
You only need a few tools to replace your AC fan motor, as the job is quite straightforward. It is advisable for you to take note of the wires before you remove your old fan motor, especially if your motor’s electrical connection is not a simple plug-in.
Before you replace the AC shroud, make sure you test your new fan motor to check for fan clearance and proper alignment.
There Is Really No Need To Bother About Fixing a Bad Compressor
If after determining that there is nothing wrong neither with the relays, switches nor with the capacitor, the RV AC compressor is still unable to function properly and cool your air, you might have to consider buying a new RV air conditioner and discarding the old one.
Unless you are able to access some used compressors and can recharge and replace the system on your own, it will probably cost too much to fix it. Most compressors last longer than their warranty.
It might be easier to have the entire AC replaced
If you have finally decided to replace your entire RV air conditioner after analyzing all these possibilities, you will have to install a brand new device. The process of replacing your older unit with a new and efficient RV AC unit is actually a simple and straightforward procedure that you can handle on your own, as we explained in this article.
Problem: Your generator is fried.
It is not like you planned it. You tried to use your microwave with the RV air conditioner on. It never occurred to you that it will be a problem. And now you are living in a hot camper or travel trailer just because your RV AC unit has stopped working.
Solution: Get a new unit and monitor your wattage.
Sorry to say this, but once your generator is fried, there is nothing you can do about it. You will just have to take it out and purchase a new one. Make sure your new unit has at least 3,100 watts (better if it has more capacity). This wattage is not enough to carry both the RV air conditioner and the microwave, (so you might want to avoid that) but it is certainly enough to power your unit through the long summer.
Problem: You tried to test the temperature and ended up killing your generator.
This particular scenario is quite common: You tried to find out if your RV thermostat is still functioning. To achieve this you had to set the temperature as low as 50 degrees making it pretty frosty.
This is not something you will do on a normal day, but you just wanted to be sure that it can actually run at that particular temperature if it had to. The RV keeps getting colder and then suddenly it stops. Your unit suddenly goes off and so does your generator.
Solution: Do not even try to test the thermostat (and you will probably have to purchase a new generator).
If you run your AC temperature extremely low, it will definitely damage your generator. So you will need to purchase a new one.
There are probably a few instances where the weather becomes so hot, that you will want to turn your RV air conditioner all the way down to 60 or 70 degrees. However, most generators cannot handle anything below 60 degrees, so take note of that.
Problem: You failed to maintain your AC unit.
You need to clean and maintain your air conditioner regularly for optimal performance.
Imagine having to install a new AC in your RV just because you couldn’t keep the components clean enough.
Solution: Regular maintenance.
Below, in this article, we have a detailed walkthrough of all the steps for planned maintenance of your RV air conditioner.
Make basic maintenance part of your routine, to avoid this. Make it a point of duty to clean your unit at least once in six months.
Once a year, you can call a professional for a more exhaustive inspection, but if you follow closely the recommendations that I provide you in this article
Problem: Your AC unit motor has become annoyingly loud.
Your RV air conditioner used to run silently when you first purchased your RV. But as time went on it became annoyingly loud and it has become a nuisance that you ignore how to fix.
Solution: It is directly in the RV AC rubber shock absorbers.
There are some plausible explanations for why your air conditioner is humming, chugging or whining louder than usual. Your shock absorbers are probably not where they ought to be. And the rumble is probably caused by their contact with the compressor coils or fan.
To fix this, remove the cover of the RV AC unit, locate the shock absorbers, and ensure that they are not touching any of the other components.
Problem: Your air conditioner is surrounded by ice!
This can be quite scary because nobody wants to see their AC surrounded by ice no matter how cold they want it to be! So what is the solution?
Solution: Replace your Freon.
Do not worry, your air conditioner is not really making ice.
All these issues are connected to your RV air conditioner Freon levels. Sometimes Freon leaks happen, and when they do, you could end up with a freezing problem.
First, you look for any liquid leak around your air conditioner. If you don’t find any, then all you need to do is to top off the Freon. Once that is done, the unit will stop making ice and produce more cold.
Problem: Your unit is leaking and you don’t know why.
You have noticed that your RV air conditioner is constantly dripping and you do not even know why. Well, this happens also with proper maintenance.
Solution: Wipe the condenser coils.
The condenser coils are supposed to minimize water condensation. And when they become dusty or dirty they will not be able to evaporate the water. This is what causes dripping. So you may want to clean those condenser coils.
Inspect the RV air conditioner condenser. The condenser coil is what gives you that perfect cooling in the summer. The condenser and coils can easily become clogged with dirt, dust, leaves, and debris, which could prevent the AC from working. Make a habit of wiping your condenser bi-annually.
Problem: Leaking RV AC unit (Not The Same As The Dripping Issue).
The dripping may have stopped, but now you are noticing pools of water around your air conditioner. You clean it up, but it continues and you are wondering where is it coming from.
Solution: Replace or tighten the gasket.
The fact that your AC unit is in a pool of water does not necessarily mean it is leaking. The water may be coming from internal or external components.
Most times, such leaks are caused by the gasket. This is located near the roof of the unit. Secure all the bolts on the gasket for a start.
Give it a little time. If the RV air conditioner continues to leak water, then you might need to get a new gasket.
Problem: The AC unit overheats and gets very hot.
Though I am not recommending that you touch your air conditioner while it is running, however, if it feels hot or releases warm air when you are near it, then something is wrong.
In fact, the RV air conditioner sometimes powers itself down when it overheats.
Solution: Cleaning The Coils And Maintenance.
If you carry out regular maintenance on your air conditioner, this shouldn’t be an issue. Overheating is one of the problems of the condenser coil. Excessive dust and dirt in the coils can make the unit hot and prevent it from working.
Problem: Your AC unit is only blowing hot or warm air.
Nobody wants to suffer through hot streams of air in the scorching weather; your AC is on because you need a little cool air in your RV. So what do you do when this happens, are you going to junk your RV AC unit?
Solution: Test your motor voltage or get another one.
Before you decide to get a new motor voltage, test it to see if it is getting adequate voltage. If you notice that it isn’t, get a professional to fix it. However, if it is getting adequate voltage but is still not working, then you might have to get a new AC unit.
Problem: The AC unit is stinky.
Despite all your efforts, you notice that your AC unit has been emitting this horrible earthly stench. You have cleaned every part of the RV, from your freezers to the kitchen and bathroom, but the smell persists (I did it).
And then you realize that the smell is actually coming from your RV air conditioner.
Solution: Change the AC’s filters and clean the radiator.
Again the problem is caused here by lack of adequate maintenance. When was the last time that you have replaced your RV air conditioner filters? This can contribute to the smell, but the radiator is actually responsible for a large chunk of this smell. If you clean it properly, the radiator should be odor-free. You can also change the filters too since it can trap some of the bad smell.
Problem: The RV AC unit is always running.
I am sure we all appreciate a diligent engine, but there is no reason for your RV air conditioner to run non-stop unless you have decided to set it that way (decision that is totally wrong, by the way). This can lessen the longevity of your device significantly, making it necessary for you to get a new one in no time.
Solution: Check the circuit board and/or thermostat.
A bad thermostat can keep your AC running even when you do not want it to run. The circuit board could also affect your unit. Whatever the cause, you should get a professional to help you fix it.
Part 2: RV Air Conditioner General Maintenance
As I mentioned at the beginning of this article, the vast majority of the RV air conditioner issues are caused because the users do not change filters, do not lubricate bearings, and do not clean coils. If the users would keep their due diligence in these simple planned maintenance activities, the RV AC units will last very long.
the vast majority of the RV air conditioner issues are caused because the users do not change filters, do not lubricate bearings, and do not clean coils
How To Access The Evaporator And Condenser Coils For Cleaning: The Removal Of The Shroud
With proper maintenance, your AC will last longer and be more efficient. Motorhome rooftop air conditioners are not different from the ones used for other RV campers like pop-up campers, travel trailers or the ones in the sidewalls like Aliner has in their a-frame campers. The maintenance and repair procedures for all these RV air conditioner devices are identical.
The efficiency and cooling power of most AC units diminish after a couple of seasons of active use. Even if the filters are cleaned regularly, the condenser coils and evaporator will be coated with grime and dirt as time goes on, and will eventually inhibit cooling efficiency and airflow.
As a precaution that you must always take, ensure that there is no electrical supply to the unit before carrying out any repair or maintenance on your RV AC unit (rooftop or not). After this, you can now go ahead and unscrew the four bolts securing the RV AC shroud to the RV air conditioner.
How to Clean Your RV AC Coils
So now you have at this step already removed the shroud. Removing the shroud will help you view the condenser coils and evaporator on both ends of your RV air conditioner.
The coils must be cleaned thoroughly to make room for unrestricted airflow.
While you can use regular household cleaners to clean the coil, they will not clean it as well as AC coil cleaners such as ZEP Foaming Coil Cleaner which is designed specifically for that purpose. This coil cleaner can also remove grime build-up without harming the coils.
For best results, follow the instructions carefully. You can use a nice wet / dry Shop-Vac to clean up subsequently and remove excess grime or cleaner from your RV AC unit.
You can also straighten the bent fins with a coil fin comb because it sometimes prevents effective airflow through the RV air conditioner coils.
These fin combs do not cost much and can be used as many times as possible on both home and RV AC coil fins.
How to Maintain An AC Fan Motor
As you remove your RV air conditioner shroud, you might also want to consider servicing your fan motor and cleaning the fan. Regardless of the producer of your RV AC unit, whether it is Duotherm, Carrier, Norcold, Dometic or Coleman, it can only have one fan motor.
You should oil the motor while at it.
An RV AC unit fan motor with regular bearings should have oiling ports at both ends of the motor. You might have to remove that metal sheeting atop your fan motor, and some sheet metal screws to gain access to its bearing oiling ports.
If you do not find any oil port, it means your motor has sleeves and not bearings. There you may need to oil the shaft. The oil automatically seeps inside which increases the lifespan of the fan motor.
Keeping Your RV Air Conditioner Covered During The Off-Season
Cover the RV AC unit whenever it is not in use. You do not even have to get an expensive cover, a cheap one will cover it just fine.
If serviced annually, you should enjoy many seasons of operation with your motorhome air conditioner. Learn to cover the RV AC unit when you are not using the motorhome.
These RV AC covers are quite affordable and can protect the unit from extreme temperatures, moisture, and debris from storms, insects, and birds. They will definitely cover their cost as time goes on.
General Cleaning Of the RV AC unit
As discussed earlier, excess dust, dirt and debris build up in your air conditioner can slow down the device or even cause it to fail completely. Though there are parts of the AC that require professional cleaning, there are still things you can do to keep your AC running properly.
I would like to insist that you have to unplug your RV air conditioner before you start cleaning. Likewise, if the device cannot be unplugged, then ensure that the RV AC unit is powered down to room temperature before you start.
Here are three areas you should concentrate on when cleaning:
- The condenser coils mentioned above. Remove the top of the AC by loosening the bolts. Use a special condenser cleaner and a handheld vacuum to clean your condenser coils
- The evaporator coils hidden underneath the RV air conditioner filters. You can also use a handheld vacuum or soft bristle brush to clean them.
- The filters. These should be cleaned every month of utilization of the RV AC unit. While some of them are disposable, there are those that can be cleaned with just soap and water. This helps you save money. However, you have to be careful when cleaning them, because any filter with rips must be thrown away.
RV Air Conditioner Maintenance And Troubleshooting Conclusions
Several times in this article, I anticipated the conclusion of this topic as follows in the paragraph below.
The majority of the RV air conditioner issues are caused because the users do not change filters, do not lubricate bearings, and do not clean coils. If the users would keep their due diligence in these simple planned maintenance activities, the RV AC units will last very long.
Therefore, almost all problems in these devices, are related to the lack of proper planned maintenance.
Air conditioning units are very important in RVs, but they cannot function on their own forever. Most of the issues people face with their RV air conditioner can be prevented through regular maintenance and cleaning. If you can stick to a six months cleaning schedule, you probably won’t have to suffer through most of the issues mentioned above.
If you have not done any maintenance on your unit in a while, you may be experiencing some of the issues mentioned above. Lucky for you, most of them are easy to fix.
Remember, your AC unit should not be handled when it is running or plugged. If there’s a problem with the circuit breaker, thermostat or other electrical components, contact a professional HVAC technician or call your RV air conditioner manufacturer to handle it.
So next time you are faced with any of these RV air conditioner issues, I am sure you will know what to do.
I am Tony, an RV designer and RV developer. I create bill of materials for RV manufacturers for travel trailers and fifth wheels. I worked as a freelance transportation consultant for Lyft. As an RV development consultant, I create customization trees for RV manufacturers who want to offer a solution to prospective customers to design their custom RV with variant configuration. Apart from this, I sell in Indiana trailer hitches, hitch balls, goosenecks and weight distribution systems where I provide advice to customers who want to know which is their towing capacity, which hitch ball should they utilize and how to deploy a weight distribution system. I do my best to explain all these processes and their installation, here in RV Favorites.