A/C humming

I have two 630516.321 on my coach. One is shutting down after running about 90 seconds then stays off for about 4.5 minutes. Is this a capacitor problem?
Jerry
What do you think Doug?

Ranger Smith wrote:
It is your control board on the AC that is bad. Mine did the same thing. Fan is shutting off but compressor is staying on.

Just a thought for anyone else with this situation, but I've found that the heating relay, if not being used, is of the same type, so un-soldering, removing and replacing same should fix it, if indeed the problem.

tropical36 wrote:
Had some issues with our dometic. Story short, after replacing the burnt out fan motor, it still wouldn't run, although the compressor always would. Disconnected the connector from the inside and checked it for burnt contacts or whatever and pulled the 3amp pcb fuse which was OK. reinstalled both and the fan took off????
Have no clue as to why except that it might have reset the control board.
About a year or two ago the old fan motor froze up. Disassembly and some grease on the bearing surfaces cured that problem until now. Did this most recent repair in this campground as I had the new motor on board and so far so good.
As a side note, the fan motor doesn't use a start capacitor and shares the run capacitor with the compressor, so one might want to consider these items in troubleshooting also.

Update:
Last trip out the fan wouldn't start again. Checked it out and it would on med and slow speed, but not on high or auto. So, after deciding we didn't really like the fan running non-stop, I went in for exploratory surgery with the thought of either replacing the high speed relay (there's three), using an external wired to the board or providing a by-pass circuit and choosing either med or low for the fan speed to operate automatically. Turns out the printed circuit itself was severed and appeared to have been burnt open. Did an easy fix by soldering a small piece of #14awg solid copper wire across the gap and it's now as good as new. Just can't believe the relay contact survived and must say the board itself is very well built. This whole assembly might be very useful in case of a new A/C replacement, as I'm not so sure one can buy a new unit that will tie in to the existing system without this add-on for control and the EMS shedding system. It does use telephone cords between the units and the thermostat.

barnaclebill wrote:

dougrainer wrote:

barnaclebill wrote:
My fault! I did not specify what I had. I have 2 Duo-Therm roof mount A/C-heat pumps and Hydro-hot heating with a 5 button thermostat. The roof units are model 630516.321 13.K BTU. I hopes this clears up any confusion, Bill

I knew what you had from your profile. You had a Monaco product and those years used the CCC system. Doug

Wash your mouth out:R I have a Newmar Mountain Aire 41' diesel pusher 400 hp Cummins turbo (MADP400SPTN):B
Thanks for all your help! Bill

Newmar uses the same system and has for almost 17 years. I THOUGHT you were the original poster. Doug

dougrainer wrote:

barnaclebill wrote:
My fault! I did not specify what I had. I have 2 Duo-Therm roof mount A/C-heat pumps and Hydro-hot heating with a 5 button thermostat. The roof units are model 630516.321 13.K BTU. I hopes this clears up any confusion, Bill

I knew what you had from your profile. You had a Monaco product and those years used the CCC system. Doug

Wash your mouth out:R I have a Newmar Mountain Aire 41' diesel pusher 400 hp Cummins turbo (MADP400SPTN):B
Thanks for all your help! Bill

barnaclebill wrote:
My fault! I did not specify what I had. I have 2 Duo-Therm roof mount A/C-heat pumps and Hydro-hot heating with a 5 button thermostat. The roof units are model 630516.321 13.K BTU. I hopes this clears up any confusion, Bill

I knew what you had from your profile. You had a Monaco product and those years used the CCC system. Doug

My fault! I did not specify what I had. I have 2 Duo-Therm roof mount A/C-heat pumps and Hydro-hot heating with a 5 button thermostat. The roof units are model 630516.321 13.K BTU. I hopes this clears up any confusion, Bill

Sorry, Right now I am out of this one. I thought your AC system was like mine. I am not up on the T-stat with 5 buttons. Gary

barnaclebill wrote:
OK, now I am confused, although I am easily confused :) is it the board on the roof unit or the thermostat board that is bad?

YOUR AC board on the upper AC unit is BAD. Doug

OK, now I am confused, although I am easily confused :) is it the board on the roof unit or the thermostat board that is bad?