AC unit froze up 8312 SS 2016

[Lookin2camp]

Second time out, 90 degrees thermostat at 70 . Unit froze, leaking small drops on kitchen floor. No cooling like usual. Thawed unit , climb down, restart , froze 20 minutes later. What's up Forest River?


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[andymil]

I'm not a HVAC tech but I've heard AC units will freeze up when they are low on refrigerant. Very annoying on a new unit.

[DaveSchwartz]

They also freeze up if you start with high humidity and not enough airflow. Try opening the cold-air quick-cool vents (the sliding grills around the edges of the ceiling bezel) when you restart after thawing.

Also, open the filter cover and ensure the freeze sensor is properly clipped to the evaporator fins. You can Google for the Airxcel/Coleman-Mach installation manual and search on the word 'freeze' within that PDF.

[TimVWulp]

Originally Posted by Lookin2camp

Second time out, 90 degrees thermostat at 70 . Unit froze, leaking small drops on kitchen floor. No cooling like usual. Thawed unit , climb down, restart , froze 20 minutes later. What's up Forest River?


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Is the fan speed on high of low? Air flow is every thing with air conditioning. Low air flow dose not bring enough warm air though the cooling coil to keep it above freezing.
I have read about some Air conditioner not positioned on the roof opening correctly causing the cold supply air to enter the return air and drop the return air temp to low. This short cycles the a/c unit air and will freeze the unit up.

Hope This Helps Tim

[Bama Rambler]

There are a lot of reasons that RV A/C's freeze up. High humidity and low air flow is a common reason. There's also a freeze coil on the evaporator coils that commonly gets left just hanging loose. They will also freeze up if there's an air leak between the discharge and return.

On our last RV the freeze coil wasn't attached to the evap coil and there was an air leak between the outlet and return. I clipped the freeze coil to the evap and sealed up the leaks with aluminum backed foam tape and it didn't freeze up the 10 years we had it.

I'd check those things and I'd run the fan on high when first starting the unit after sitting off for a while.

[SeaDog]

My experience with both home and commercial units is that freezing up is caused by low refrigerant or plugged (dirty) return air filter.

[pkeene]

What happens is that folks close off some of the AC ceiling vents to "increase" flow to other areas of the coach. Many time this reduces overall air flow to a point where the AC unit will freeze up. Keep all of the vents open if "freeze-up" is an issue.

[Lookin2camp]

Thanks for the advice by all. The unit only turns on and blows air when the high or low fan speed is on or in auto . The unit will not kick on just by adjusting the thermostat. If I just switch it to cool the unit does nothing. Thinking this could be a thermostat issue, but why won't it cool? Freon leak out? I cleaned the roof unit and drip pan , which increased the water drip flow, however the unit never froze back up, but never cooled either. Both filters were cleaned too. Drop off CW On Wed this week. Irritated 😡🙄🙃


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[hillsdaletc]

Pull the ceiling cover or filter cover down , look up inside and you will see a sensor that should be pushed into the finned area. The sensor will , if properly in place , sense temp and shut off compressor if freezing begins. This is for high humidity days. It could be it was not put in place when it was installed at the plant.

[dahagen]

My AC froze up several times on the Texas coast this winter. But it never does it in the mountains of the West. I would think that hi humidity is the problem.

[tomrob1161]

High temp and high humidity, run fan on high. The unit will work a lot more efficiently and not ice up. At night when the temp drops turn the fan back to auto. This was a recommendation by a Dometic A/C factory rep.

[Wolverine 1945]

Originally Posted by andymil

I'm not a HVAC tech but I've heard AC units will freeze up when they are low on refrigerant. Very annoying on a new unit.

RIGHT ON Andy !!!
Low on Refrigerant or Low air flow ???

[SLOArmada]

Originally Posted by hillsdaletc

Pull the ceiling cover or filter cover down , look up inside and you will see a sensor that should be pushed into the finned area. The sensor will , if properly in place , sense temp and shut off compressor if freezing begins. This is for high humidity days. It could be it was not put in place when it was installed at the plant.

Our A/C unit froze up several times in a row last summer (in the Mojave Desert). Had to run it with the compressor off and fan on to blow the air over the ice to thaw it out in about 10 to 15 minutes (being 100+ degrees also helped thaw it out quickly...)

After getting tired of it continually freezing up and it being over 90 degrees inside, I did the above to check on the thermocouple sensor placement. It was pushed into the fins at the bottom by the drip tray where it never freezes. The fins above would be covered in a thick layer of ice.

I simply pulled the thermocouple temp sensor out of its incorrect position and pushed it back into the fins much higher up ( near the middle where the ice first forms). Never froze up again. It was always as cool inside as we wanted it to be for the rest of our 6 week trip through the desert southwest in August!

[Lookin2camp]

Thanks for all the positive experiences. My issue was covered under warranty ( only 2 months old) haha. This was two things , the freeze sensor was bad and not hooked up properly. My thermostat was bad too. Everything replaced by CW. The was checked and not ammonia based product leaked out. (No freon in these units )

We'll see how it works end of the month at the beach


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[Flybob]

X2 on using quick cool dump vent when first turning on while hot and humid. Once unit cools down and reduces humidity it can be closed and use the duct vents.

[bob dirt]

Originally Posted by Lookin2camp

Thanks for all the positive experiences. My issue was covered under warranty ( only 2 months old) haha. This was two things , the freeze sensor was bad and not hooked up properly. My thermostat was bad too. Everything replaced by CagW. The was checked and not ammonia based product leaked out. (No freon in these units )

We'll see how it works end of the month at the beach


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Glad you got it fixed. Having no AC sucks in the summer time.
Not understanding your last sentence though. You are showing a picture of a compressor designed to pump refrigerant (aka freon which is a brand name).
Ammonia can't be used with copper lines like the ones brazed to your compressor.Also ammonia is used in absorption units like a propane fridge and even 12 volt AC units. It is heated by propane or electric elements. The nomenclature tag on your unit should identify the refrigerant being used.
Maybe there is a new refrigerant out that I'm not familiar with (highly likely). I have been in the HVAC business for 40 years (started at 18)and the last couple of years I have semi-retired and have not kept up in the world.
A lot of these AC threads have gotten me curious about leaks, control boards and what not. When I get back home this week I'm pulling the top off of mine to see what has changed over the years besides the type of refrigerant. They used to use R12 and R-22 with mechanical controllers. The last I new of was R-134a and under-rated (amps)solid state control boards.

[Lookin2camp]

This is the reason I'm posting pics. I'm not sure myself but I am being told this. I'm trying to learn these things as I go. Here is the info pic of the sticker on this unit. Unfortunately I don't have a pic of what was froze , but it was the coper line. Please respond


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[DaveSchwartz]

R-410A is a 50/50 mixture of R-32 (difluoromethane) and R-125 (pentafluoroethane) - no ammonia involved. Would have been just the freeze sensor involved in it freezing up. I thought it might be mis-positioned but didn't count on it being bad too. Thermostat would not have had anything to do with it freezing up... just not running at the times or conditions expected.

[bob dirt]

Originally Posted by DaveSchwartz

R-410A is a 50/50 mixture of R-32 (difluoromethane) and R-125 (pentafluoroethane) - no ammonia involved. Would have been just the freeze sensor involved in it freezing up. I thought it might be mis-positioned but didn't count on it being bad too. Thermostat would not have had anything to do with it freezing up... just not running at the times or conditions expected.

What he said^^^^^^


If 410A is being used in these units, no wonder they are leaking. It runs very high pressures.

[Lookin2camp]

Ok I'll run this thing in my driveway on the next hot day. If it doesn't cool I'll address CW. Can I check the levels of the 410A ? Or not accessible with the proper tools? apparently CW doesn't understand the system, which now im very concerned. Glad I posted pics. On the flip side , I'm hoping it was a freeze sensor issue. Thanks


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