A/C Acting Funny

[clange]

Hi all -

Looking for some feedback on air conditioning problems that we ran into on our trip to Yellowstone and back. The AC worked great when we ran it prior to leaving on the trip. We traveled to Colorado Springs where we spent 3 days with the AC running during most of that stay. On the last day, it appears that the unit was freezing up, because the airflow diminished to almost nil and after 45 minutes of sitting there turned off, it ran just fine.

Following our stay at Colorado Springs, we traveled to Yellowstone where the AC worked just fine when we needed it (not too often, which is unheard of for people from S Texas in the summer ). It worked just fine at all of our other stops until our last night in Waco, TX where it blew all night and I realized that the compressor would not start. I cycled power to the unit by killing the breaker for a few minutes - still no luck. The next evening, after arriving home, the compressor and AC worked just fine, and is working fine today.

I'm perplexed...any ideas as to what may be going on? It's a Dometic Duo-Therm 15k unit with the wall mounted thermostat.

Thanks!

[Bama Rambler]

The freezing up could be caused by the freeze sensor not clipped to the evap coils, or not in the right place. It's common to see that.

While you have the grill off looking for that, look to make sure that the duct is sealed to the unit and that there's no open space between the outlet and return sections.

[325BH]

Originally Posted by clange

Hi all -

Looking for some feedback on air conditioning problems that we ran into on our trip to Yellowstone and back. The AC worked great when we ran it prior to leaving on the trip. We traveled to Colorado Springs where we spent 3 days with the AC running during most of that stay. On the last day, it appears that the unit was freezing up, because the airflow diminished to almost nil and after 45 minutes of sitting there turned off, it ran just fine.

Following our stay at Colorado Springs, we traveled to Yellowstone where the AC worked just fine when we needed it (not too often, which is unheard of for people from S Texas in the summer ). It worked just fine at all of our other stops until our last night in Waco, TX where it blew all night and I realized that the compressor would not start. I cycled power to the unit by killing the breaker for a few minutes - still no luck. The next evening, after arriving home, the compressor and AC worked just fine, and is working fine today.

I'm perplexed...any ideas as to what may be going on? It's a Dometic Duo-Therm 15k unit with the wall mounted thermostat.

Thanks!

Low refrigerant can cause freezing, however that doesn't sound like your problem.

Remember, the fan in your air conditioner moves air across the evaporator (the part that is freezing up). Heat is transferred from the air to the refrigerant in the evaporator. This heat transfer does two things: cools the air and warms the evaporator. When it is hot outside and the air conditioner is working hard, the evaporator probably never freezes up. When the temp is not as hot outside and the air conditioner isn't working that hard, it can freeze up if there is not enough air being blown across the evaporator.

Try switching your fan on to high instead of low or auto. This will keep airflow moving across (through) the evaporator even when the compressor turns off. This should keep it thawed out.

If you have a big air conditioner and not a very big camper, and your air conditioner cycles on and off a lot, the air conditioner doesn't run long enough to remove the humidity... which has the moisture to freeze. If the air conditioner shuts down and the air movement stops, that wet air can freeze on the evaporator... further blocking airflow, which compounds the problem.