Furnace not working

enblethen wrote:

Looks like contacts are in control unit.

When you say "control unit" are you talking about the Comfort Control center inside the coach, which I think most people call the thermostat, or are you referring to the circuitry in the roof top heat pump? I haven't been on the roof yet but it seems so far that the contacts controlling the furnace are not closing since the test I did jumping the 2 blue wires at the furnace made the furnace come on. So if I go on the roof and one blue wire has 12 volts and the other never gets 12 volts, that will reaffirm that the contacts are not closing. But then we are back to are the contacts/relay bad or is the relay not being told to close.

Once I get the roof top unit open and get my memory refreshed I will know a lot more. Thanks for the help everyone.

Not sure about wiring of your system, but some have a relay to prevent the AC from operating at the same time furnace.
Furnace should provide it's own power and relies on a contact closure for operation from the thermostat.
Looks like contacts are in control unit. Have you checked the mode functions in the zone for furnace operation?
From manual:
If a furnace is operated by the Comfort Control Center, the thermostat wires are attached to the two (2) blue wires from the control box. The furnace dip switch for that zone (control box or power module) is turned on

I did that and furnace came on and made heat. So my next step will be to see if that power is getting to the a/c circuit board and coming back out of it.

You can jumper the blue wires at the furnace.

Thanks Doug. I'll go on the roof when the rain stops. One of the blue wires at the furnace has power and when jumped together there, the furnace works. But of course that does not mean the power is making it up to the roof.

If the furnace "shows" on the tstat, it has the correct DIP switch turned on for the furnace. BUT, if the furnace is malfunctioning or the furnace FUSE is blown it will not operate. It will still show furnace on the CCC if the furnace fuse is blown.
Unless you REPLACE the other AC/HP, you cannot use the new CCC after replacing the new board in the new Penguin. 5 button and 10 button control boards are not compatible and your rear penguin would not have worked with the 5 button system if it had the 10 button board. Doug

PS as I explained, you have a FURNACE problem , not a Dometic control problem. If you want to take the time, go up to the Front Penguin board. The 2 BLUE wires on the board are the furnace wires. Jump them together. IF the furnace does NOT come ON, you have a furnace problem. Also, 1 of those 2 blue wires should have 12 volts from the furnace. IF you have NO 12 volts on either blue wire, you have a furnace problem.

It is a Duo-therm 5 button Comfort Control unit. I haven't done a reset yet. I am sort of under the impression that if the a/c's and heat pumps work and "furnace" shows on the thermostat that it doesn't need to be reset. But I could be wrong.

What is make and model of thermostat?
Have you tried resetting the thermostat? Procedure varies with different makes and models.

Thanks for the links. The furnace shows on the thermostat. It's just when I select furnace and adjust up to 80 degrees(it's 60 out right now), nothing happens. This all started a few weeks ago when it was 40 out and I needed it but it wouldn't come on. Luckily, it was warm enough that the heat pumps still worked good.

I'll read through the links and see what I can figure out

http://bryantrv.com/docs2/docs/ccc5.pdf

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

There is a wire from the front AC down to the heater.
Also do a reset on the thermostat and see if your heater shows back up before you start tearing into things. You should print these out if you do not have them.

If the AC are working then thermostat should be working but ensure you have the heater selected after you do the reset.