Coleman AC freezing up

[mlj427]

I have a 2013 Coachman with 2 Coleman 15k AC units. They were running fine with the fans on high yesterday and last night I came in today at noon outside temp around 90 it was 85 inside and both ACs running both were frozen. I turned them over to fan only and checked the filters and even used my phone to look inside the duct work to be sure it was clear. No problems found. Any idea why both would freeze up on a hot day? Definitely ruined the weekend.
Any help would be appreciated.
Thanks
Mike

[DutchmenSport]

Good point here. When I switched out my 13,500 btu for the current 15,000 it seemed it just didn't cool right. I was disappointed.

I removed the cover inside the camper, took out the air filter and exposed everything and studied it out. The cardboard divider between the intake side and the output side was just hanging and had gaps allowing the intake to suck the out take air before it even had a chance to blow into the ducts or even the center blast.

I used tape for aluminum stove pipe - extremely strong stuff and no second chances with it - touch it anywhere and it don't move again. It's silver color, extremely resilient to heat and cold as it's designed to take heat from a furnace for a gas water heater exhaust. (High temperature).

Anyway, I taped up all the cracks and holes and then the puppy worked fantastic!

As stated above, it's possible your cold air is being recirculated in over and over and over again, never allowing warmer air over the coils, thus causing the freezing.

I agree, check inside and make sure you have good separation between intake and output sides. Some tape goes a long way.

[dougrainer]

mlj427 wrote:
Talked to the dealer service guy and Coleman’s service dept and they both think that the baffles between the return and output is letting the cold air leak into the return. So I will pull the lower shroud and seal any leaks then clean the coil. I will see how it goes.
Thanks

Get and use the FOIL CHROME AC tape.,. DO NOT use duct tape. I was going to mention making sure the air box is sealed correctly. One thing tho, your Freeze Thermister wire has debris all over it. That shows your Filter is not installed correctly or it is worn out. The only place dirt can come from is the interior of your RV and the filters stop that. At least most of it. Doug

[mlj427]

Talked to the dealer service guy and Coleman’s service dept and they both think that the baffles between the return and output is letting the cold air leak into the return. So I will pull the lower shroud and seal any leaks then clean the coil. I will see how it goes.
Thanks

[wolfe10]

Best to buy an evaporator cleaner (most box stores), put old towels, etc under the duct so you don't get water in the interior and clean the evaporator and condenser from the roof.

[mlj427]

I will be going down one day this week to vacuum the coil, pull the inside trim and make sure the baffles that keep the cold air away from the return air are in place and will check the freeze sensor location.

[time2roll]

Yes move the freeze sensor to where you see the frost.

[dougrainer]

j-d wrote:
I'd call that Coil...Dirty.

AND he needs to move the Freeze Thermister UP about 4 inches. THAT will fix his problem. Doug

[j-d]

I'd call that Coil...Dirty.

[mlj427]

[dougrainer]

mlj427 wrote:
Mine have wall mounted thermostats, both have the little sensors pushed into the coil when you look up through the filter opening. There is a very small amount of dust on the filter side of the coil. I will try vacuuming it next time I go down to the camper. I have a picture of the dust when the front AC started to freeze but can’t see how to post.

Thanks
Mike

Replace BOTH of the Freeze Thermisters. Regardless of the condition of the AC parts/parameters, with functioning Freeze Thermisters, the AC CANNOT freeze up. Doug

[mlj427]

Mine have wall mounted thermostats, both have the little sensors pushed into the coil when you look up through the filter opening. There is a very small amount of dust on the filter side of the coil. I will try vacuuming it next time I go down to the camper. I have a picture of the dust when the front AC started to freeze but can’t see how to post.

Thanks
Mike

[wa8yxm]

Question Where is the Thermosat/fan/mode switch.

IS it in the ceiling grill? or wall mounted.

Reason for asking.
Many Wall mount controlled units have a 'Frost Sensor" that is a thermal sensor stuck right into the evaporator coils. If it starts to ice up the compressor is shut down for a while.

Coleman "Local control" (Ceiling knobs) do not have this sensor.

How do I know this. ONe is just to my right as I type.. yes it will Ice up
The carrier controlled unit in the back (not a carrier A/C but Carrier controls) has a frost sensor so it should not ice.

[dougrainer]

If you have WALL Tstats, it should NEVER freeze up regardless of how you operate it or the ambient conditions. It has a FREEZE Thermister to prevent it. If it freezes up, either the Freeze Thermister is not installed/correctly or it is defective. To have 2 fail at the same time points to not being installed.
IF you have knob roof top manual control knobs, then freezing is a possibility. The only thing you can do is make sure the Condensor and Evaporator are clean and the AC filters are clea. Run the units on HI COOL and back off the Tstat knob slightly from full cold. Doug

[ksg5000]

Freeze sensor may have shifted/fallen off - worth a look.