Dometic AC problem

[jscott689]

Fans runs, compressor sounds at though it kicks on, but the air coming out is not cold. When we attempt to run Fan on Auto from the thermostat, the unit does not come on at all. The only way it runs is if we go to the "Cool" setting. We have checked the wires going in to the thermostat and they are all intact. We have also tried re-initializing the thermostat. Any other "simple checks" before we take it for service?

[travelin texans]

Your ac will ONLY run when set to "cool", ONLY the furnace will run if set to "heat" unless you have a heat pump. The fan if set to "auto" will ONLY run when ac starts, if fan is set to "hi" or "lo" it will run constantly whether ac starts or not. The ac fan will not run with the "heat" setting , only the furnace fan.

[chuckster57]

Fan on Hi or Lo, the AC fan will run when heat is chosen.

If your compressor isn’t starting, you need to do some diagnostics at the control board. Located in the return, behind the ceiling grill.

[jscott689]

Originally Posted by travelin texans

Your ac will ONLY run when set to "cool", ONLY the furnace will run if set to "heat" unless you have a heat pump. The fan if set to "auto" will ONLY run when ac starts, if fan is set to "hi" or "lo" it will run constantly whether ac starts or not. The ac fan will not run with the "heat" setting , only the furnace fan.

Thanks for the info. We initially thought it was a problem with the roof unit but then read something about someone only being able to get theirs to work setting it to auto instead of cool. We will direct our attention back to the roof unit vs. the thermostat.

[wiredgeorge]

Fan in auto will only kick on when the A/C is in COOL mode; in FAN mode the fan just runs. The system seems to take forever to cool on a hot day as it is pulling in hot air and you can expect about 20 degrees difference in the cooled air versus ambient air. If you believe the compressor is kicking on, let the thing have a chance to cool. Turn the A/C on in the early morning to keep the trailer cool and try and park the trailer in shade. There are also many things that can be done to make the A/C more effective inside the trailer... lots of threads on these things.

[jscott689]

We had the unit checked out by today and it needs replaced. Is there anything special we would need to do to upgrade the 13500 to a 15000 since we have to replace it?

[chuckster57]

Originally Posted by jscott689

We had the unit checked out by today and it needs replaced. Is there anything special we would need to do to upgrade the 13500 to a 15000 since we have to replace it?

No there isn’t.