Domestic ac freeze up

itguy08 wrote:

dougrainer wrote:

You are WRONG. Freeze sensor WILL stop it from freezing regardless of conditions or Freon level as long as it is installed correctly. They may have told you it was low on 410 but I doubt it was. HOW did you(they) determine it was low on 410? Doug

I am not wrong. If you Google Evaporator freeze up, low freon is listed as one of the top symptoms (as is airflow). Google frozen evaporator and you'll see plenty of pics of partially frozen coils!

When these newer Dometics lose Freon they do freeze up despite the sensor. It's been a common issue from 2013-2016. Supposedly there was an issue with corrosion and a leak will form. Or it's poor tubing + increased pressures from the new R410a.

On our 15k Dometic, new in 2015 the sensor was jammed up 1/2-2/3 the way to the top of the evaporator. Nice and secure wedged in the fans. The sensor can't detect freeze ups if it's not in the path of the cold.

When we had the most recent failure this year on Father's Day weekend, the weather was low 80s and we were parked in the shade. Started out on Friday taking forever to cool the camper with little water being produced despite it being very humid. Finally shut off sometime in the night and then would ice over on low or high. It never got the camper to 74 degrees and outlet temps were only in the high 50's after running for a long time. It would also send shards of ice throughout the ducts and leave a puddle on the floor. I got up on the roof and tore into it and noticed that the top 1/3 to 1/2 of the evaporator was frozen solid, above the sensor. Following the piping the expansion valve is on the top of the evaporator and that's where it was freezing - above the freeze sensor!

The previous failure was a similar thing but no ice - it just would never cool the camper despite running all night and day. IIRC discharge temps on that were maybe 5 degrees below ambient.

When they replaced the units cooling performance has been restored to perfect. It will run near all day on automatic fan (with low speed) and will cool in a decent amount of time. Water comes off it at a more normal rate.

Sorry, IF the Freeze sensor is installed correctly, NOTHING will cause a Freeze up. I WORK on RV's for a living and have and still do for 38 years. I see more Dometic AC's in 3 months in the summer than all combined on these forums. I also NEVER see a Low charged unit. IF the unit is low charged it is because of a leak and after about 30 days the 410 or 22 will be GONE. They only hold 16 ozs of coolant. LOW charge from Dometic is almost non existant. I REPEAT my question, HOW do/did you determine they were LOW charged or had a leak? Google????? Well, The internet is NEVER wrong or has Factually inaccurate information. Doug