Rooftop A/C

[huling3]

I have a 2003 Ambassador with two Duo-Therm roof A/C units. The front unit now comes on without the customary lag time and may or may not get around to producing cold air. Thermostat no longer controls anything except the main off/on switch for the front unit. Rear unit works as it should. I doubt the problem is the thermostat but I can't find a control board. I would think there is some controller to keep both units from cycling on at the same time etc. Does anyone know where this phantom control box is located or am I thinking wrong?

[dickandlois]

huling3,

There should be a name and or part number on the climate control you use to set the temperature and fan speed.

The control board is connected to the thermostat by a cable that looks lick one used on the desk style telephones.

The control boards are often placed near the controls for the converter / chargers and the 12 volt and 110 volt breaker and fuses boxes.

Note: It is quite common for the electronics to fail inside the thermostat. Often one AC unit or furnace works and the other will not work.

Rich.

[huling3]

Rich

The only names on the control/thermostat is Comfort Control & Duotherm . When I popped the control box off the wall I'm looking at the back side of a circuit board. I dis-assembled the controller and a # shows up on both sides of the board 50-981501-B. It maybe the comfort control board is the only board in play. If so, a new control/thermostat is probably the only answer. It is not serviceable.

Fred

[dickandlois]

Fred, This is a link to the owners manual. I will see what I can find.

http://media.channelblade.com/EProWebsiteMedia/1844/Duo_Therm_Comfort_Control_Manual.pdf

Rich.

Try this link.

http://bryantrv.com/docs2/docs/ccc.pdf

[huling3]

Rich

Thanks, this opened up a couple of possibilities. I'm just not sure how to proceed from here. I think I'll just take into a dealer. With control/thermostat being solid state I'm thinking the unit itself has a problem.

I took the roof cover off to clean it the other day when the problem first started. The problem unit had a large birds nest. It appeared to be a work in progress. I cleaned it up, fan was quiet and smooth and A/C kicked in however, as before without the normal delay. After that the cooling cycle was uncontrollable. Possible something in the roof unit is messed up as a result of the nest. If so, what? I have no idea when the nest could have started or how long it's been there. I didn't see any problems such as signs of overheating but I'm not a a/c guy.

I appreciate your input and the links. It really helped the thought process.

Thanks again,

Fred