Furnace/AC issues

You just joined. Need Year Model of RV Need Brand and model of roof AC and TYPE tstat. There are dozens of possibles out there. PIC of the wall tstat would help. Doug

dougrainer wrote:
You just joined. Need Year Model of RV Need Brand and model of roof AC and TYPE tstat. There are dozens of possibles out there. PIC of the wall tstat would help. Doug

Thanks for the reply, I'll have to figure it how to upload pictures. It's a 2004 Fleetwood Pioneer. The AC unit is an 8000 series by RVproducts. The thermostat is a Coleman-Mach. It kinda looks like the whole system might be a Coleman-Mach, because the thermostat's picture is in the owner's manual of the AC unit.

I'll work on getting the pictures uploaded

MildlyCompetent wrote:
Recently got a 2004 Fleetwood Pioneer. The A/C was working, but we finally hooked up an LP tank to test the water heater, furnace, etc, and after switching it to the furnace, it won't move back to AC. Any advice?

Thanks!

T-stat has a heat and a cool setting. Youn need to pick which you want. The auto setting is for the A/C fan only.

cavie wrote:

MildlyCompetent wrote:
Recently got a 2004 Fleetwood Pioneer. The A/C was working, but we finally hooked up an LP tank to test the water heater, furnace, etc, and after switching it to the furnace, it won't move back to AC. Any advice?

Thanks!

T-stat has a heat and a cool setting. Youn need to pick which you want. The auto setting is for the A/C fan only.

The thermostat is set for AC, fan is on high auto, and the temp is 55, and that's how it was functioning before the switch to the furnace. I can try it with the fan set to "on" again, but I don't think that was the issue

RVP and Coleman---same company. Kind of like GM and Chevy. Doug

TO THOSE WHO ARE GOOGLING IN YEARS TO COME: Here's what we've learned so far: Something in the furnace went bad. The 12v power source for the thermostat goes through the circuit board of the furnace. If we jump across from the main 12v fuse box to the power supply on the thermostat, the AC kicks on normally. The circuit board on the furnace should have a flashing indicator light, but it isn't working, so probably we're looking at swapping out just that circuit board, or (more likely) putting in a permanent bypass from a fuse in the box to the thermostat. I'll update if we come up with a different diagnosis, but it's looking like that's it.

MildlyCompetent wrote:
TO THOSE WHO ARE GOOGLING IN YEARS TO COME: Here's what we've learned so far: Something in the furnace went bad. The 12v power source for the thermostat goes through the circuit board of the furnace. If we jump across from the main 12v fuse box to the power supply on the thermostat, the AC kicks on normally. The circuit board on the furnace should have a flashing indicator light, but it isn't working, so probably we're looking at swapping out just that circuit board, or (more likely) putting in a permanent bypass from a fuse in the box to the thermostat. I'll update if we come up with a different diagnosis, but it's looking like that's it.

NO NO NO! You are close to the solution tho. The power for the Wall tstat does come from the furnace 12 volt wire. You have 4 wires at the furnace
1. 12 volt pos
2. Neg(ground)
3. Tstat feed (12 volt pos)
4. Return wire from wall tstat that will be 12 volt pos to engage the furnace to run
What Brand Furnace do you have and is this furnace mounted with an outside access door outside the RV? The power does NOT-NOT go thru the furnace circuit board for the wall tstat. One of the 2 wires(3 & 4) should have 12 volt power. If not, there may be a 12 volt circuit breaker on the furnace that is tripped. Doug

Im going to go out on a limb here, if it worked before you switched to from ac to heat, and dosen't work now the first thing i would look at is the thermostat itself. Jump the wire see if the ac runs.