I had the thermostat set so it wouldn't get too cold in here, like I always do. Had it set to "low cool." Woke to a/c sounding very bad. Shut it off, opened the hatch inside the coach and found the condenser was a solid, smooth, equally thick (all over) sheet of ice.I have the hatch open and I put a bunch of paper towels in there to hopefully catch most of the water as it melts. I've been using the a/c pretty much on a daily basis since I moved into the RV on June 19th. This has never happened before.To reiterate, I didn't have the a/c set to full cold, I had it set to only keep the rig from being too hot overnight. Thanks for your input. We're in the midst of an August scorcher. Not a good time for this to happen, and I just (last night, in fact) loaned my mother my big floor fan.

First be sure filters are clean. There should be two settings. Fan speed, and the thermostat. To get though this trip, set fan speed on high. Set thermostat so the compressor kicks off at about 75 degrees. Give that a try and see if that stops the icing.Theoretically these shouldn't ice up. But they often do. Be sure filters are clean. Be sure there is good airflow and cold air doesn't immediately recycle back through AC unit via missing duct tape or bad duct work. Sometimes no matter what you try they'll ice up on occasion.

Thank you. I tried to just put it on "fan only" to get the room temperature air to help it to defrost but there's simply no air able to move through the condenser at this point in time. I shut it off and will just have to wait for some of it to melt, then I can turn the fan on and that should help to quicken things up.I'll check for the tape and other things you mentioned to make sure the system is tight.

If your A/C has been working correctly in similar weather until last night with the same settings, it would be safe to assume that unless the filters were exceptionally dirty, the cause is the A/C itself, not faulty installation, or improper fan settings. With that said, the #1 cause of any A/C freezing up is low coolant, and that is probably your problem as well.

Never run the, ac on low, unless using Heat or just the fan

Get a hair dryer and push warm air into it. That will start the melting process. As it gets hot today it will start to melt quickly.After check to see that filters are clean. I lived full time for 4 1/2 years, part of it here in high humidity and high heat. I learned to keep the fan on high and the filters clean. Good luck, this would have to happen on the hottest days of the year.

Roof a/c froze into a block of ice overnight. | Good Sam Community

21 Replies

Cheryl_B
Explorer
Aug 11, 2016
Okay. Thank you for explaining that to me.

It's fine now. It melted enough for me to turn the thermostat all the way to warm and I put the fan on (only have "low" for just the fan.) Ice came shooting out the air vents as it melted and I let it just do its thing until that stopped. Let it air out as much as I could, then turned it to cold and on high (high cool, full thermostat.)

Leaving the cover off of it so I can peak in every so often to see if it reices. (A new word!) Thanks for the help. I'll stop using the low setting.
tpi
Explorer
Aug 11, 2016
To thaw turn AC fan on high. Plenum divider is taped, duct or foil section which separates the intake air from the output air. If it leaks, it recirculates cold air-causing evaporator to run too cold.

But often these icing conditions are just what you describe. It works perfectly most of the time, then one scenario of usage sets off the icing. The evaporator coils on these AC units are on the ragged edge of being too small-and running too cold. For packaging purposes. Speeding up the fan raises evaporator temperature and lowers risk of icing.
Cheryl_B
Explorer
Aug 11, 2016
There's nothing stuck in the ice. I have a blow dryer but can't afford to buy a new one, so I will only use that to hasten the thawing if I have to. "Air plenum divider"? Not sure what that is. Will check for anything that looks wrong and try to repair. Just odd for this to happen out of the blue when I am using it the way I always have.
time2roll
Nomad
Aug 11, 2016
Did you look for the freeze sensor? Was it in the ice or was it poorly installed so it would fall away from the evaporator?

While you are in there check the air plenum divider on the inside. Very common for this divider to be poorly installed and allow chilled air to circulate back into the machine instead of directed out to the RV.
tpi
Explorer
Aug 11, 2016
No filters on the roof. These units have to be perfect not to freeze. And often they aren't..ducting is too restrictive, recirculating cold air, freeze sensors located incorrectly. The two best antidotes to get you through: high fan speed, and set the thermostat high enough the compressor shuts off before the icing occurs.
Cheryl_B
Explorer
Aug 11, 2016
I know, right?? It's all a test.

I am a consummate newbie so how do you put coolant in a roof a/c? Go up on the roof and pull off the cover and add it there?

Never run the a/c on low? Even when the thermostat is not left on high or even medium high? Again, newbie question. And I've done that often and never had an issue.

Filter's fine. Are there more filters up on the roof section of it? I have to confess that I'm rather large and I haven't walked on the roof yet. Scares the manure out of me.
Chrisatthebeach
Explorer
Aug 11, 2016
Get a hair dryer and push warm air into it. That will start the melting process. As it gets hot today it will start to melt quickly.

After check to see that filters are clean. I lived full time for 4 1/2 years, part of it here in high humidity and high heat. I learned to keep the fan on high and the filters clean.

Good luck, this would have to happen on the hottest days of the year.
newman_fulltime
Explorer II
Aug 11, 2016
Never run the, ac on low, unless using Heat or just the fan
DownTheAvenue
Explorer
Aug 11, 2016
If your A/C has been working correctly in similar weather until last night with the same settings, it would be safe to assume that unless the filters were exceptionally dirty, the cause is the A/C itself, not faulty installation, or improper fan settings. With that said, the #1 cause of any A/C freezing up is low coolant, and that is probably your problem as well.
Cheryl_B
Explorer
Aug 11, 2016
Thank you. I tried to just put it on "fan only" to get the room temperature air to help it to defrost but there's simply no air able to move through the condenser at this point in time. I shut it off and will just have to wait for some of it to melt, then I can turn the fan on and that should help to quicken things up.

I'll check for the tape and other things you mentioned to make sure the system is tight.

Forum Discussion

Roof a/c froze into a block of ice overnight.

21 Replies

About Motorhome Group

Related Content

Turnbuckle blocks gas cap

Jacks froze on wood blocks

Walmart overnight parking

Pink stuff froze

Froze black/grey tanks....