RV Air Conditioner 101 for Newbies

Willy2027 wrote:
As a Newbie I have some questions about using my AC unit.
1-the tech at the RV dealer said to use my AC unit on AC high only and not use it on AC low. He stated that if I used it on AC low that there is a chance of the AC unit freezing up. Has anyone else experenced this?

2-When my TT is unoccupied in a RV park for 2-3 days should I run the AC unit to keep it cool and also help the refrigerator to keep cool?

3-Any other useful info on AC units is appreciated.

Here's my minor variation of the theme.
1. I'd run it on high when I was away till you get to know it. Yes properly running ACs don't freeze, but I've sure had those that do freeze under certain possibly rare conditions. These are not issues I take it in for repair after I've checked location of freeze sensor (if equipped)and possibility of recirculating cold air. You can work around the freezing by keeping fan speed high, filters clean, and thermostat set mid 70s or higher. When you're around experiment with the lower fan settings, they may work fine. Or they may work fine in certain weather conditions and not others.

2. Like above I'd set it to 80. That way it is very unlikely to freeze unsupervised.

3. If it is expected to be extremely hot, get a good head start cooling in the morning.

DownTheAvenue wrote:
A properly installed and functioning RV should operate successfully in any climate with the fan on high or low speed.

Correct.
The number one reason I have found for a freezing coil is dirty filters.
Second most common problem was missing foam tape or defecticpve sealing tape between the intake (return) section and the output (supply) section.

I would guess that either Lo or High might be helpful. Setting the fan on Auto would be my least preferred IMHO.

Thanks to all for your comments and suggestions!

It depends WHERE you are at.
For years I only RV'd in the Midwest. Air cond worked just fine high or low speed and I never cleaned the coils.

Went to Florida.....because of the high humidity mold forms on the coils and you have to REGULARLY clean it off. And as stated above from people in high humidity low fan is what is used to prevent freeze ups.

First month in Florida during the summer and Thought my ac surely was dead. All the RV mobile guy did was clean the coil of the green mold and bamm I had cold air.

If your AC freezes up on low fan it is likely low on freon. Dometic ACs have a freeze sensor that cycles the compressor if the coils start to freeze. If the sensor falls down out of the coil it won't do it's job. Running on high fan will add insurance to prevent freeze up. I sure dislike the noise of high fan.

Q1-the tech at the RV dealer said to use my AC unit on AC high only and not use it on AC low. He stated that if I used it on AC low that there is a chance of the AC unit freezing up. Has anyone else experienced this?a

A1-I have heard of it and understand the theory but it should not happen if the A/C is working properly and the filters are clean.


q2-When my TT is unoccupied in a RV park for 2-3 days should I run the AC unit to keep it cool and also help the refrigerator to keep cool?

A2-I would so long as there is food in the fridge... However some parks have rules against eitehr that, or leaving it unoccupied for more than one night.

q3-Any other useful info on AC units is appreciated.

A3-Clean and inspect at least once (if not twice) a year

Clean filters at start of season and monthly during season

At least once a year (Or twice if full timing) go up on the roof, Remove the outer cover and inner cover and clean the condensor, inspect and clean blower and if needed evaporator coils, Inspect and clean fan, Inspect and clean anything else you can inspect and clean.

Insects may build a nest on the fan causing serious vibration when you start up.. So cleaning at the start of season indicated.

Finally.. NOISE.. Many folks complain of NOISE.. Setting the FAN to HIGH and letting it run all the time will not reduce the noise.

But the human brain is a marvalous thing and it will soon "filter" out the noise and then the as an added benefit the fan noise will cover the sound of the neighbor's knock down drag out fight allowing you to sleep all night long.

DownTheAvenue wrote:
A properly installed and functioning RV should operate successfully in any climate with the fan on high or low speed.

Here in north texas we have awful humidity/heat and it drips like crazy, but never freezes. I almost always have it on low speed.

Every other month i climb up top and pressure wash and air hose the unit so it doesnt crave amps under a load.

A/C Units Icing


And THANKS to Chris Bryant this LINK is a good read about RV A/C Units

A properly installed and functioning RV should operate successfully in any climate with the fan on high or low speed.