Air Conditioner not working

[DonandBonnie]

We just tried to use the AC for the first time this season. It comes on for anywhere from 2 to 10 seconds then shuts off. The thermostat returns to calling for heat. It is Dometic and the Auto switch is on. Any suggestions? We have not used the AC since last fall.

[bncinwv]

My first thought is to reset the thermostat. The procedure should be in the manual.
Bingo

[Irlpguy]

Here is a thought, if the thermostat is on Auto and the temperature you want is set at say 70 degrees but the ambient temp is less than 70 then the AC would look at that and say, whoa, it is already as cold as you want so you must want heat to warm the room so lets switch over to the furnace. If your propane is on does the furnace then try to come on, you say it goes back to calling for heat.

I don't run mine on Auto but I could sure go and try this to see what happens if that would be of use to you.

[DonandBonnie]

Not sure if the gremlins are at work or not. As we said on the original post the AC would default back to furnace after a few seconds. The system was on Auto. The fan would not start, even when changing over from Auto. Furnace thermostat is set on 71, AC on 72. The indoor/outdoor thermometer read 83 inside and 86 outside. Long about 8 o'clock tonight the AC started running. Neither of us touched any settings, nor had we made any attempt to restart after our first post. Indoor/outdoor temps had dropped a couple degrees but were still above the thermostat settings. The AC has worked as intended from that time forward. We have absolutely no idea what has changed to cause the AC to operate.

[Irlpguy]

"Auto" just decided it was spring and came out of hibernation.... Glad it is now working.