penguin II AC issue

[12th_Man_Fan]

Having an issue with one of my Dometic Penguin II heat pump/AC. When the weather is hot the AC works fine. Since we got up here in the mountains where it is fairly cool it is acting crazy. I can set the temp to 74 and during the day it will cycle just fine but when it gets a little cooler in the evening It will not cut off and it quits cooling.

I suspect freeze up but I have tried running it with the fan on high but it still quits cooling. I have cut it off and back on with same results.

If it is freezing what can I do to fix it? My front unit works like a champ.

By the way when the compressor is running and I change the fan speeds I can't hear a change in the speed. When I have it on the fan setting I can hear the change of speeds.

I appreciate your feedback for ideas. I am about ready to swap the front an rear because we use it a lot more than the front.

By the way, it works perfectly on the heat pump mode.

[12th_Man_Fan]

I have a 2014 RV and both AC's were replaced in 2014.

Thanks Doug for your reply I am trying to locate something that shows me where the thermister should be placed. If all else fails I can look at the front AC and see where it is. As I said it works fine.

[dougrainer]

lj2654 wrote:
I have been told to run the a/c fan on high instead of auto.....why or what it does I have no idea.....

Because ill informed people state to do this. If you have a wall tstat your AC system has a Freeze Thermister. Doug

[dougrainer]

If it freezes up, the output air would be very minimal. You need to check the Freeze Thermister to make sure it is installed and in the correct place. You don't state what year you have but the Dometic wall tstats will have a obvious pause between Fan speed changes. If you want to test the Auto function fan speed, make a 10 degree hi setting from the RV actual temp. It will go to HI fan, after a few minutes manually drop the set temp down to 3 to 4 degrees from the set temp and wait, you should observe the fan to stop for a split second and then start on LO fan. Doug

PS, if you suspect freeze up a simple way to verify this is to put the AC in FAN only mode and if frozen you will see a LOT of melted water run off the roof within a few minutes

[lj2654]

I have been told to run the a/c fan on high instead of auto.....why or what it does I have no idea.....