Community Forums

BobbyT49 · 01-01-2022, 12:57 PM

Hi to all and Happy New Year,
I've been having an ongoing problem with my forward furnace not operating, but, honestly, living in Florida I haven't made it a top priority. I have power at the switch and the circuit breaker, but doesn't seem to have any power going to the board when turned on. The rear furnace fires right up. While looking through some maintenance slips from the previous owner, I came across one from 4/2020 that states after installing a new thermostat he had a problem with the A/C units. His complaint was that he had to unplug and reset to change zones. The repair facility stated that the cause was "upper control board not registering if it is a master or a slave. Will not program to zone 2 defaulting to zone 1". The service they performed was " Replace upper control board and set flip switches to correct zone. Customer OK with using both A/C units on same zone. Programmed to same zone so one comes on and then the 2nd comes on after a brief pause. Both working now".
First off, I'm wondering if this has anything to do with one furnace not getting a signal from the thermostat to turn on. I called the previous owner, but he wasn't sure if the last time he used that furnace was before or after the thermostat change.
Secondly, UPPER CONTROL BOARD, FLIP SWITCHES, and REMOTE.
If anyone could shed some light and what they're referring to or where these would be located, I would be grateful.
Incidentally, I have a 2003 Revolution 38A with 2 Atwood 8535-IV furnaces with an RV Comfort.ZC thermostat.

Thanks in advance and Happy New Year to all.

Old-Biscuit · 01-02-2022, 10:48 AM

Does the thermostat for front furnace have Heat setting in Zone 1?
*suspect it does for Zone 2/rear furnace

Jumpers / Switches....those are on the A/C Control Module (circuit board) in ceiling return area of A/C Unit

See....RV Comfort ZC Manual
http://old.rvcomfort.com/rvp/pdf_documents/1976659.pdf

BobbyT49 · 01-02-2022, 12:05 PM

Thanks Old-Biscuit,
I surely appreciate you sharing your knowledge. As soon as I get a chance to get the coach home again, I'll check that out. The link was a different model than mine, but I'm sure the wiring is similar.

Thanks again and Happy New Year

Old-Biscuit · 01-02-2022, 01:11 PM

See pgs 11-13+ for more info
http://old.rvcomfort.com/pdf_documents/1976342.pdf

radar · 01-02-2022, 01:26 PM

We had an issue with our front furnace on our 2003 Revolution. But in our case it was an intermittent connection at the furnace from the wire harness. I don’t think I ever found the exact issue. It seems to me It had something to do with the switch that was the furnace. It’s the switch you see when you take off the cover. Seems to me I hardwired around the switch and it went away but not sure if it wasn’t something else in the wire harness.

Sorry I can’t be of more help. Just for giggles you might try fiddling with the harness or maybe bypass that switch. Wish I could remember more of the logic path I followed but that was like 10 years ago.

Good luck.

BobbyT49 · 01-02-2022, 05:56 PM

Thanks radar,
I have power to that switch and the CB after the switch.. I'm thinking it's more of a thermostat issue. Thankfully Old Biscuit forwarded some links to help me troubleshoot it further. As I said, being in Florida it's not a priority right now, but I'll track it down.
Thanks for the reply.

radar · 01-02-2022, 06:02 PM

Quote:

Originally Posted by BobbyT49

Thanks radar,
I have power to that switch and the CB after the switch.. I'm thinking it's more of a thermostat issue. Thankfully Old Biscuit forwarded some links to help me troubleshoot it further. As I said, being in Florida it's not a priority right now, but I'll track it down.
Thanks for the reply.

No problem. Good luck.