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Why Does My RV Air Conditioner Freeze Up?

The worst possible time for your RV air conditioner to freeze up is on a trip during the warmer months. However, that’s usually when a problem occurs.

Why does my RV air conditioner freeze up? Here are six common reasons for your AC to freeze up:

  1. Dirty evaporator/condenser coils
  2. Bad baffle
  3. Dirty air filter
  4. High humidity
  5. Broken thermostat
  6. Low refrigerant

1. Dirty Condenser/Evaporator Coils

The primary reason that your RV air conditioner might freeze up is because the condenser of evaporator coils are dirty. You should be taking the time to clean these coils on a regular basis because they are what makes your AC work efficiently. The evaporator coils pull the hot air out and the condenser coils push the air out.

If dirt has accumulated, there’s not enough surface area to allow this to happen, so the unit must work harder to cool things off. This leads to ice buildup because the AC is working harder than it should have to.

How To Clean Condenser/Evaporator Coils

In this section, we’ll look at the steps for cleaning your condenser/evaporator coils:

  1. Turn unit off
  2. Remove the covers
  3. Vacuum coils
  4. Clean coils
  5. Repeat process (if you need to)
  6. Inspect coils
  7. Dry and put back together

While this process might seem a bit time consuming, it’s worth it n the long run. By performing a little maintenance like this, you’ll be able to keep your AC running longer.

2. Bad Baffle 

The second reason your RV air conditioner might freeze up is due to a bad baffle, also known as flow divider, to keep the cooled air separate from the warm air. If there’s not a good seal between the two, the cooled air will leak into the warm area, which means the AC would be working harder to cool the already cooled air.

This is a pretty easy fix: simply reposition the baffle. You can use HVAC tape to keep it in place and avoid this issue in the future.

3. Dirty Air Filters

The air filters in your home AC get dirty, so it’s only logical that the air filters in your RV air conditioner would also get dirty. This reduces the ability of the unit to pull the warm air in, which means the AC will freeze up.

You need to be cleaning the filter at least once a month during the months that you’re traveling a lot. Wipe off any accumulated dust/dirt and then wash with soap and water. If you have the time, prepare a vinegar/water solution and allow to soak for up to 15 minutes and let air dry overnight.

Additionally, you should be replacing the filter every year. These can be found online and in home improvement stores and are fairly inexpensive.

4. High Humidity

One of the major factors in how your RV air conditioner functions is the amount of humidity in the air. On days with high humidity, your AC is working as hard as it can to pull the heat out of the air- but it just can’t seem to keep up. Try running the fan on high to avoid your unit freezing up. If that doesn’t work, try cleaning your unit, especially if it’s been a while.

If you typically enjoy vacationing in places where humidity is high, you might want to purchase a dehumidifier. this will help pull the moisture out of the air so the AC doesn’t have to work so hard. You could also pop open your vents for about 10 to 20 minutes to pull the moisture out. You don’t want to leave them open too long though, that would be counterproductive.

5. Broken Thermostat

If you have to keep turning down your AC thermostat to cool your RV off, and you’ve already ruled out the above reasons for your AC freezing up, your thermostat may be broken.

If your unit (and thermostat) are older, its advisable to replace it anyway because of the inaccuracy of the older models. Follow these steps to check your thermostat accuracy:

  1. Check temp with a thermometer
  2. Compare your results with your thermostat reading

If the readings are close the toe same, the thermostat is not the problem. If they are different, your thermostat is malfunctioning. Replacing the thermostat is pretty easy, but if you’re not comfortable with minor electrical work, you’ll want to hire a professional.

6. Low Refrigerant

The final- and least likely- reason that your RV air conditioner might be freezing up is low refrigerant. RV air conditioner systems are sealed, so unless there’s a leak, you’re not going to lose refrigerant.

Plus, since the system is closed and, ideally, there’s nowhere for the refrigerant to go- you can’t add more to it. You may be able to have a technician install a service port so refrigerant can be added- but typically, it’s much less expensive to just replace the unit.

If your RV is new and you are experiencing a refrigerant leak, check the warranty to see if you are covered. If your air conditioner is freezing and you’ve checked all of the above issues, hopefully you can have your unit replaced if it’s still under warranty.

Since most people vacation during the warmer months, it’s almost a necessity to have an air conditioner that works in many locales. However, there are a few reasons that an air conditioner might freeze up and not work properly. If your RV air conditioner is freezing up, it may be one of the above reasons. If you’ve tried everything that you can and its still giving you problems, you may consider replacing the air conditioner.

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