Informational Guide

RV AC Not Blowing Cold Air? (Common Issues and How To Fix)

RV air conditioners can be tricky to diagnose. See how to fix an AC in your RV that is not blowing cold air anymore.

by Josh M

Recreational Vehicles (RVs) are a great way to go on vacation without the expense and hassle of a flight and hotel. They give you the freedom to enjoy the country and independence to go and stay where you like. The only downside to RVs is that they’re much more susceptible to the elements than a traditional home.

In your RV, your air conditioner is important to help keep you cool in the hot summer weather. If your RV AC starts to malfunction, it can become really uncomfortable, so you need to get it sorted quickly.

A common issue is that an RV air conditioner is not blowing cold air. This guide will explain why this happens and how you can fix the problem as quickly as possible.

Before we talk about solutions, let’s talk about the problem and why it’s happening. There are quite a few reasons that your AC isn’t blowing cold air, but we’ve given a list of the most common problems:

Recreational Travel Camping with an RV

Thermostat Problem

More often than not, if the air isn’t blowing cold, then it’s an issue with the thermostat. This is usually because of an issue with the thermostat itself or the temperature sensor. Check the display and see if it’s flickering or if it’s no longer showing at all. You may need to examine the power source or replace the thermostat because otherwise, there’s nothing to control the AC temperature.

Fan Problem

If your fan isn’t spinning at the right speed, then you won’t get cold air blowing into your RV. This could be caused by a faulty motor or some kind of blockage in the machine. If you can smell burning, it means your fan is trying to run but meeting resistance, but you’ll need to sort the problem quickly because it can be a fire hazard.

Low Freon Level

Freon is the coolant within your AC that lowers the temperature of the air as it passes through. For the process to work, it is shifted between liquid and gas through your evaporator coils, and over time, this can reduce the amount of freon within the device. This will limit the cooling effect and stop cool air from blowing in.

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Dirty Compressor

Your compressor and its components are used to cool the air as it comes into your RV. If they aren’t functioning correctly, then you won’t get any cold airflow. This could be because some parts of the car ac compressor needs to be replaced, but it could also be because they need to be cleaned. Regular cleaning of your coils and fins may help solve the problem.

Burned Out Capacitor

Your capacitor helps power your device by storing a small amount of electricity to help your AC start up. Over time these can become faulty and may need to be replaced or rewired. If your device is humming loudly or not blowing cold air, then it’s a sign that there’s an issue with your capacitor.

Important Elements Need To Be Checked On RV AC

If you start to notice any issues with the RV AC, like a change in temperature or a strange noise, then there are some specific parts you should check. These components should be checked annually even if there are no specific issues, and regular cleaning and maintenance will keep your AC running properly. Make sure you turn the power off entirely before checking any of the elements, so there’s no risk of injury.

Air Filter

Your air filter helps to keep dirt and other debris out of your RV. However, it can become blocked over time, limiting the flow of cool air, and can cause your AC to overheat. If you notice hot air coming into your RV, you should go and check the air filter, which is located inside your AC.

You can usually open your AC by hand, or use a screwdriver if you have a closed access panel, and access the filter. Slide it out and look for dirt and debris blocking it. Cleaning the RV AC filter regularly is a good way to avoid the issue.

Evaporator Coil

Your evaporator coil works to cool the air within the AC by absorbing the heat. If you notice warm air coming through, it’s usually a sign that something is wrong with the coil, and you’ll need to check it. The evaporator coil is usually found on the inside part of the AC and near the air handler.

Usually, you can just open a panel and access it easily enough, but you should use your user manual to help guide you here. You won’t be able to remove the coil, but you can use a vacuum to get rid of dirt and debris around it. Remember, even if there are no issues, you should be checking your evaporator coil annually to make sure there are no hidden problems.

Evaporator Coil of an AC
Condenser Coil

Your condenser coil is a series of tubes that hold freon or refrigerant. Warm air passes over these coils and cools it down so that it can pass into your RV. If warm air is coming into your RV, the AC keeps turning off and on, or there’s an unusual sound coming from the AC, then it could mean there’s an issue with the coil.

Your condenser coil is in the outer part of the RV AC just behind the fins. You should be able to lift a panel off the exterior unit to access the coil. You shouldn’t need to remove them, but you can check for any dirt or debris that might put a strain on the device. Check for any visible damage and consult with an HVAC professional if you’re not sure.

Fan Blower

Your blower is responsible for pushing the cool air into your home after it’s passed over the evaporator and condenser coils. If your AC is running slowly, starts making rattling noises, or there’s no cold airflow, then it can be an issue with the fan blower.

The fan blower is usually located inside the RV, near where the ducts enter the vehicle. To access this, you’ll usually need to unscrew a panel, but you should check your user manual for instructions. Once inside, you should look for any damage, blockages, or other noticeable issues with the fan. You may be able to fix this yourself, or you may need to ask a professional for help.

Ducts

Your ducts are essentially the pathways the air will travel down. If you start to notice a reduction in airflow, uneven temperatures, or a dodgy smell coming from your AC, it’s typically because of something in the ducts. You’ll need to check the individual lines, starting with the exterior, and look for any blockages or visible holes. You can probably repair them, but it may take a while to find the actual problem.

Thermostat

Your thermostat controls the temperature of air coming into your RV, and without it, you will get hot air coming in. If you feel like you aren’t controlling the temperature, then there may be an issue with the thermostat.

You should check your thermostat display screen to check that it’s working properly. If nothing is coming up on the screen or the display is flickering, it could mean there’s an issue with the electricity supply or wiring. There are usually some AA batteries in the back of the thermostat, so start by replacing these and see if it resolves the issue. If not, you may need to replace the thermostat, but this can usually be done relatively simply.

Stelpro Thermostat

How To Fix RV AC Not Blowing Cold Air

As you can see, there are a few different reasons why your RV AC might not be blowing cold air, but here’s a quick guide to help you troubleshoot the problem and fix it.

1. Gather Your Supplies

Start by getting some protective gloves, dusting cloth, soapy water, compressed air, vacuum cleaner, and screwdriver.

2. Switch Off The AC

Start by turning off the air conditioner. Make sure it’s completely switched off, or it could be dangerous to put your hands near the mechanism.

3. Check The Thermostat

Start by checking the thermostat on the AC. The display should come on and show the temperature and settings clearly. If there’s any issue, then try replacing the batteries and check the wiring. If the wires have become frayed, or the thermostat still doesn’t work, then you’ll need to replace the thermostat.

This is pretty easy to do yourself, just buy a replacement thermostat from your hardware store, turn off the old thermostat, remove the wires, and then wire your new thermostat into the same place. Then, switch it back on, and it should work fine.

If the issue isn’t with your thermostat, or this doesn’t solve the issue, then move on to the next step.

4. Clean The Air Filter

Sometimes the filter in your AC can become so blocked that it clogs up the device and stops it from working correctly. Your air filter should be located within the interior unit and easy to access. Pull it out and use the compressed air to blow the dirt clean.

Take a wet cloth and wipe it over the filter before putting it back in. Some air conditioners will need the air filter to be replaced periodically, so check your user manual and replace it if needed.

Replace the filter and see if cold air starts to flow. If not, move on to the next step.

Related ArticleHow to Clean RV AC Filter

Man with Mask Cleaning AC Filter
5. Check The Fan

If you notice a burning smell or a different sound from the AC, you should check the fan. Start by opening the AC unit, following the user manual for instructions, and checking for any damage. Use the compressed air to remove any dust and debris and see if this does the trick.

If not, you’ll need to replace the fan. This can usually just be unscrewed, removed, and replaced with a new fan from the hardware store. Close up the hatch and see if this has resolved the issue; hopefully, it’s now working.

If this doesn’t help, or you don’t think the fan is the issue, then move on to the next step.

6. Check The Compressor

If you still have a problem, it could be an issue with the compressor or one of its components. Go to the outside unit and start by cleaning the fins. Leaves and other debris can block the vents here and impact the machine’s performance, so it’s essential to clean them as much as possible. Then, open up the outdoor unit using your screwdriver and look inside. Use a vacuum and compressed air to clean out any dust and remove any other debris that might have got inside. Focus particularly on the coils, as these can pick up a lot of dirt.

Once you’ve cleaned and dusted the interior, you should check the freon level in the machine. If there’s any ice or frost building up, it probably needs to be restocked. You can go and buy a can of freon from any hardware store but check your individual user manual to see if they recommend something specific. You should also check the user manual for instructions on how to top it up.

Finally, take a good look around the inside of the unit. Take a flashlight and look for any loose connections, broken parts, or rogue items that might be blocking the device. Take your time and fix anything that can be fixed here.

Once you’re done, close it back up and turn the unit on. Hopefully, the unit starts to blow cold air, but if not, move on to the last step.

7. Consult A Professional

If your AC still isn’t working, then it’s time to contact an HVAC professional to come and look through the device. They’ll be able to test your ducts and other hard-to-reach components to see what the issue is. Hopefully, they can resolve it, but if not, they’ll probably be able to advise on the next steps. It will probably cost between $200 and $400 to get a professional involved depending on the nature of the issue and the time taken to resolve it.

How Cold Should an RV Air Conditioner Blow?

Your RV isn’t built to deal with extreme or freezing temperatures, and anything under -20 degrees Fahrenheit can damage the machine. So ideally, you would keep your RV around 75-80 degrees Fahrenheit for optimum comfort. Of course, some people prefer it hotter or colder, but this tends to be the sweet spot.

Remember, your RV isn’t as well insulated as your home, so you need to use your AC slightly differently. You shouldn’t need to run it at night because it will get a lot colder, but during the hot days, you’ll probably need to run it for longer.

Popular RV Air Conditioner Brands Not Blowing Cold Air

Every AC is slightly different, and they’ll face their own unique problems. Here’s a quick guide for how to deal with common issues faced by two popular RV AC brands:

Dometic

Dometic 640315C Penguin IIDometic RV air conditioners are pretty popular and work in the same way as any other AC. Alongside the components above, there’s also a common issue of leaking on the exterior box.

It’s worthwhile taking some weather seal foam and applying it around the edges, and then using foil tape to secure it in place. This should help prevent leaks which can damage the interior.

The other common issue with Dometic RV ACs is the ducts coming loose or developing small leaks.

This could impact the cold air coming through. The easiest solution is to use duct foil and foil tape to secure the edges of your ducts to hold them in place. This should prevent any problems before they arise.

Coleman Mach

Coleman Mach 3The Coleman Mach range of AC units is pretty good and popular with RV owners. Some users have experienced issues with the thermostat, though, and when they try to run the AC at less than 72 degrees is shorts the circuit.

You should carefully check all the wiring and ensure it’s all correct and aligns with the user guide. If you notice anything off, you should replace the thermostat on the air conditioner, and it should work fine.

People Also Ask (FAQ)

How do I reset my Dometic RV AC?

To reset a Dometic RV AC, you need to hold the + button on the device and the on/off button for 3-5 seconds. The display will show – and should then reset.

How long do RV air conditioners usually last?

An RV AC should last between 3 and 5 years if you maintain it properly.

How often should I check the refrigerant levels in an RV air conditioning system?

Your AC should never really run out of freon if your device is working properly, so you should only really check it if you think there’s a problem. However, it can be prudent to check the AC every year just to make sure nothing is leaking.

How much does it cost to fix this issue at a mechanic?

Replacing an RV AC can cost between $1000 and $2000. General repair work can cost anywhere from $200 to $700, depending on exactly what needs to be done.

Conclusion

RV air conditioning is important and can be the difference between a relaxing holiday and a sweatbox. However, if your AC stops blowing cold, you need to act quickly. Hopefully, this guide has given you some valuable information to get your RV air conditioning running properly again.

Related ArticleRV AC Troubleshooting Guide

Last Updated on March 14, 2022

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.

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