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How to Keep an RV Air Conditioner from Freezing Up

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Last Updated on June 25, 2022 by Jessica Lauren Vine

If you’re trying to beat the heat on a summer day by hunkering down in an air-conditioned space, you might be wondering how to keep an RV air conditioner from freezing up. There are few things more frustrating than if your AC isn’t working as it should. If you suddenly notice little to no air coming out of your vents and the inside temperature of your RV is skyrocketing, you’re likely in the middle of an air conditioner freeze-up. 

RV air conditioners freeze up for many of the same reasons that residential air conditioners do. Most of the reasons include insufficient airflow, faulty mechanicals, or humidity and temperature differences. It’s essential that you get to the bottom of what’s causing your air conditioner to freeze up and fix the problem.

Whether you live in an RV full-time or are simply trying to enjoy a weekend trip, but your AC keeps freezing, you’ve come to the right place. Several things could be causing a lack of airflow or faulty mechanicals, and this article will explain each of them. We’ll also discuss what you need to do to fix them and how to keep the problem from happening again. 

What Does Freezing Up Mean With an Air Conditioner? 

First and foremost, I should explain what it means for an air conditioner to “freeze up.” A freeze-up happens when the evaporator or condenser coils on your air conditioner get covered in ice. If this happens, all or part of your refrigeration lines are likely frozen, which will cause your air conditioner to stop circulating air. 

A freeze-up won’t necessarily cause your air conditioner to shut down, but it will severely restrict its effectiveness. Freeze-ups will block the flow of air coming out of your air conditioner, and you’ll feel little to no air coming out of your vents. Freeze-ups can also cause damage to your compressor and other components on your air conditioner. 

What Causes an RV Air Conditioner to Freeze Up and How to Fix It? 

Now that you have a better idea of what a freeze-up is and what it looks like let’s dive into why it’s happening. 

Dirty Air Filters 

The most common reason for an RV air conditioner freeze-up is because your air filters are dirty. The air filters are located on the underside of rooftop air conditioning units on the inside of your RV. The air conditioner works by sucking the air out of your RV and circulating it over super-chilled coils before sending it back into your camper. Your air filter’s job is to capture dirt, debris, and other nasties and keep them from circulating through your air conditioner. 

However, when your air filter gets too dirty, it will block airflow altogether. This, in turn, will mean that there’s not enough air circulating over your coils and could overwork your air conditioner. Freeze-ups are the most common result of dirty air filters. 

How to Fix 

To clean your air filters, you should start by turning off your air conditioner. Remove the filters from the bottom side of the unit, and wash them by running lukewarm or cool water over them. Wipe them down and make sure they’re totally dry before re-installing them and turning your air conditioner back on. 

Dirty Condensor or Evaporator Coils 

Dirty condenser or evaporator coils will have a similar effect to dirty air filters. The job of your coils is to remove the heat out of the air that gets sucked out of the RV and then cool it down before it gets sent back into the camper. If the coils are dirty, however, there isn’t enough surface area to remove heat and cool at the same time. The result is an overworked air conditioner and a freeze-up. 

How to Fix

As with your air filter problem, the only way to remedy freeze-ups caused by dirty coils is to clean them. Because the coils are on the actual air conditioning unit on your RV’s roof, cleaning them is more complicated than cleaning your air filters. Here’s what you need to do. 

  1. Turn off the air conditioner and flip the breaker or remove the fuse that provides power to it.
  2. Get on your RV’s roof and remove the outer shroud or protective cover on top of your air conditioner. 
  3. Watch out for bees and wasps, as they like to make themselves at home underneath your AC cover. 
  4. Use a vacuum cleaner or shop vac to sweep off the coils. 
  5. Next, use a garden hose to spray the coils off. 
  6. Make sure they’re as clean as possible, then put the cover back on the AC. 
  7. Go back inside your RV, turn the air conditioner on, and see if the problem is remedied. 

Low Refrigerant 

Refrigerant or freon is the lifeblood of how your air conditioner operates. It’s a super-cooled liquid that circulates through your air conditioner’s coils and copper tubes and cools the air as it’s flowing over the top of them. Once the air is chilled, it gets sent back into your RV. 

RV air conditioners are designed to have a specific amount of refrigerant inside them. Too much refrigerant could cause damage to your compressor. Insufficient refrigerant, however, will cause your air conditioner to freeze up because there isn’t enough freon to cool the air while removing humidity from it. 

How to Fix

The only way to gauge the amount of freon in your air conditioning system is with air conditioning gauges and the knowledge of how to use them. This is a job best left to HVAC professionals who have the proper training and equipment. HVAC pros will be able to measure your refrigerant levels and add or remove freon as needed. 

Too Much Humidity 

While your air conditioner’s primary job is to generate cold air to pass through your RV, it also serves a secondary purpose. As your AC is supercooling the air, it also removes humidity. This excess humidity rolls off the air conditioner, flows along your roof, and drips off the side of your camper. 

However, there are times when the air contains so much humidity that your air conditioner isn’t able to keep up with it. The humidity forms on the evaporator and condenser coils faster than it can flow off. Because the coils are super-chilled, it can lead to the humidity freezing on them before it has a chance to escape. 

How to Fix 

The best and only way to prevent this problem from happening is to run your air conditioner fan on the HIGH setting. Running your AC fan on high is usually enough to ensure that air is moving swiftly enough over your coils to keep them from freezing. 

Your Fan or Blower is Broken 

Your fan or blower is one of the most critical components of your air conditioner. While the refrigerant, condenser, coils, and copper pipes do the job of cooling the air, your fan is what circulates it. It’s responsible for sucking the air out of your RV and through your air filters before blowing it back into your unit after it’s become icy cold. 

If the fan isn’t working properly, it may still suck the air out of your RV, but there’s nothing to blow it back inside your camper after the coils have cooled it down. As a result, the cold air sits on top of your coils and will quickly cause the moisture and humidity on them to freeze up. 

How to Fix

Repairing a broken or damaged fan on your air conditioner is tricky work best left to the professionals. It’s likely that your fan will need to be replaced and unless you have electrical and HVAC experience, you shouldn’t attempt to diagnose and perform the replacement yourself. 

It’s Too Cold at Night 

If your RV air conditioner only freezes up at night, it’s probably too cold outside. Attempting to run your AC when it’s 65 degrees or less could cause it to freeze up and shut down. 

How to Fix

If freeze-ups only occur during the night when the air is cooler, this is likely what’s causing your freeze-ups. To keep the problem from continuing, simply turn off your air conditioner at night. If it’s too warm inside your camper, simply open some windows so that the night air can cool down the interior. 

What to Do When My RV AC Freezes Up? 

If you’re in the middle of a freeze-up, you’ll first have to fix the frozen coils before you can start troubleshooting possible issues and performing repairs. If you notice that your air conditioner is in the middle of a freeze-up, here’s what you should do. 

  1. Shut off the air conditioner. 
  2. Go atop your RV and remove the shroud covering your air conditioner. 
  3. If the coils are frozen, you’ll have to give them ample time to unfreeze. 
  4. While the sun should make quick work of the ice, you can speed up the process with a hairdryer or leafblower. 
  5. You can also run your air conditioner on FAN mode. 
  6. Once the ice has melted, you can turn the AC back on and see if the problem persists. 
  7. If it does, repeat the de-icing process and start troubleshooting possible causes from the list above. 

RV AC Freezing Up Frequently Asked Questions

Here are some questions you might have relating to your RV AC.

Why does an RV AC freeze up?

RV air conditioners usually freeze up because of dirty air filters, dirty condensers, broken fans or blowers or too much humidity.

Do RV air conditioners operate on propane?

No. You need battery or shore power to run your air conditioner.

Should I cover my RV air conditioner?

Yes. The more you can protect your RV air conditioner, the better.

RV AC Freezing Up – Conclusion

Air conditioner freeze-ups are extremely inconvenient, and they’re also dangerous to the health of your compressor. Running your AC too long during a freeze-up will cause serious damage to the compressor, and you might have to replace your entire system. For that reason, it’s vital that you pay attention to your air conditioner and take note of changes in how it operates. Even a subtle change could indicate a major problem that needs immediate repairs. 

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