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jerry davis · 02-19-2015, 02:55 PM

When it's not real warm we usually run only the rear AC for peace and quiet. Yesterday, we parked and switched on the rear AC and it immediately fired up instead of waiting for the usual 1-2 minute delay. Then it would not shut down by raising the thermostat setting no matter how high we set the temp. It would shut down if we turned the mode off the cool setting. The front AC works normally.
This is an area I know little about so would appreciate some advice on where to start troubleshooting.

wa8yxm · 02-19-2015, 03:09 PM

Without the make and model of the Air Conditioner's lower unit it is hard to say anyting but it sounds like a control board failure.

Could be as simple as a bug in the control board.. NO, not that kind of bug, The six legged kind of bug (insect) which can be blown away with compressed air. Could be a bad board, Could be a bad T-Stat (If it came on blower only) or if the delay is in the T-Stat not the A/C.)

Janet and Todd · 02-19-2015, 03:14 PM

We had to swap out our thermostat. The new one freaks out occasionally so I have to remove the fuse or do a three finger reset. You might also try a Vansco reboot.

JLMunsil · 02-19-2015, 03:30 PM

Check to be sure the fan is on auto setting for that zone. If on any other setting ( hi, low, et ) the fan will start as soon as you put it on a/c.

Janet and Todd · 02-19-2015, 03:41 PM

Good point, Jim. I can't tell from inside our coach if the compressor is running or not when the fan is on. The immediate start and not turning off no matter how high the thermostat is set could indicate that the fan was selected to be on as opposed to "auto" start and stop.

DrDaveMA · 02-19-2015, 09:30 PM

Jerry, I also use the AC in the zone we are not (front AC when sleeping, rear when we are awake to keep the noise down) I noticed we have a delay in the front AC, when nothing starts (no fan or compressor) for a few minutes, but the rear unit seems to turn on immediately. I don't remember if you have the heat pump or not could, it make a difference in the operation.

I replaced the thermostat and the front AC about 3 years ago, so I am probably configured differently. I know there is a control board in both units, the rear slaves off the front. So I would look at the Tstat and both control boards (I think they are the same board, just optioned (jumpered) differently. Call/email me if I can help.

Kudos on being in an area where you need the AC, we are in the 60's during the day, but mid 30's to 40's at night (got to 35 last night, but we are due 75 on Saturday.

Dave

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jerry davis · 02-21-2015, 06:34 AM

Sometimes when you are a dumb a.. you have to admit it as Yogi Berra might say. Jim, you were right. Somehow the fan setting got changed off auto for the rear zone. I blamed the DW and she blamed DA.

Learn so much from this forum. Thanks!