2015 Cougar 337FLS Air Conditioner

[ToBNamedL8r]

My AC runs fine (fan in auto) but occasionally the fan shuts off for a few seconds while the compressor continues to run. Then it kicks back on. It sounds like it may be changing speed but it's hard to tell. Anyone else have this experience?

[MarkS]

That happens to me sometimes. The AC has a two speed fan. The Thermostat switches speeds when the temperature gets 5 degrees (I think it is 5) above set point. I think sometimes the AC can't quite get the temperature to go down through that 5 degree difference.

I don't think it hurts anything, but if I hear it happen a couple of times, I switch the thermostat to Hi Fan.

[ToBNamedL8r]

Thanks. That's what gave me the clue that it might be changing fan speeds - when I switched the fan from auto to high and it switched the fan off then back on high. I still haven't found anything in the documentation about this though.

[JRTJH]

The A/C fan operation isn't described in the air conditioner manual, rather it's in the Dometic Digital Thermostat manual. On page 11 of the "single zone thermostat" operation it describes the fan speed sequence in the "AUTO" mode.

"Auto Fan When auto fan is selected the fan speed will vary depending on the difference between the temperature set-point and the room tempera- ture. In auto fan the compressor and fan cycle On and Off with the thermostat. When the difference is:
>5º The fan operates on HIGH
<4º The fan operates on LOW

Compressor Time Delay A time delay of approximately two minutes occurs any time the compressor is required to begin the cooling or heat pump cycle.

Power Interruption In the event the power to the air conditioner or control is interrupted, the system will restart with the previous set points once power is restored."

So, to further explain, when the inside temperature approaches 4*F of the thermostat set point, the fan stops, changes speed and then resumes in LOW. If the temperature rises, the fan again stops, changes to HIGH and then resumes at the new speed. The compressor continues to run during these fan speed changes. If the compressor turned off, there would be a 2 minute delay (to equalize head pressure) before it came back on. Keeping the compressor running eliminates the need to "restart it" after a delay in cooling.




Hope this explains it well enough.