Help! Hooking back up the Atwood 8012 furnace.

[Tford]

Ok, I give up…
Here are two pictures, the first is 4 of the wires that come out of the ceiling when you’ve removed your Dometic A/C. The red and black pair go to the thermostat. The green and white pair are usually blue and the green is 12+V and the white has been continuity traced to the blue connector in the furnace that the schematic says goes to the sail switch.
The second picture is the thermostat location, with the same red/black combo from the roof and a black 12- ground. I reckon the Dometic thermostat had three wires for heat and cooling functions between the two units.
So threads I’ve found that have removed the A/C say to hook the green 12+ to the thermostat red and the white to the thermostat black. Tried it and no go with furnace operation, I’ve even reversed the two on WH1/RH to no avail. I’m pretty sure that extra black 12- wire factors in here somewhere but I haven’t hooked it together with the black wire at the thermostat until I try to get some advice!

[rubicon327]

The thermostat is just a make/break. Based on your description of the wiring if you touch the white and green wire at the roof together it should complete the circuit and bring the furnace on. Does this happen?

[Tford]

I’ll try it! Methinks I’ll be searching “Atwood furnace won’t come on” threads and looking at sail switches next!

[Tford]

Bingo! Just for good measure, I blew a bunch of compressed air into the heater (with a small dust bunny or two coming out!). Then connecting the wires at the ceiling, ON comes the heater AND heats, then I connected all the involved wires at their respective locations, ceiling and thermo, and the heater came on again. Seems like I might possibly have a faulty thermostat…..so I’ll try troubleshooting it! Heck, it’s brand new and never been used at this point! It clicks, but no heater….

[rubicon327]

Originally Posted by Tford

Bingo! Just for good measure, I blew a bunch of compressed air into the heater (with a small dust bunny or two coming out!). Then connecting the wires at the ceiling, ON comes the heater AND heats, then I connected all the involved wires at their respective locations, ceiling and thermo, and the heater came on again. Seems like I might possibly have a faulty thermostat…..so I’ll try troubleshooting it! Heck, it’s brand new and never been used at this point! It clicks, but no heater….

You got it now. If the heater comes on when connecting green to white you know you've got a complete circuit and working furnace. Then connecting green 12V+ to red and the white to black you should now have continuity on the two conductors down to the thermostat location. If you then jumper red and black at the thermostat location and the heater comes on you are all set. Red should go on RH and black on W1. Check the spread on the gold connectors next to each terminal. If they are too wide the prongs from the front section will not make good contact. Your top tabs in particular look pretty wide but I would tighten both up by pinching them towards each other.

Safe off that extra black wire. I would have expected the other end of that wire to also be up at the rooftop unit as it was a control wire from the original Dometic thermostat that probably told the system to initiate heating or cooling.

[Tford]

Well, it’s the thermostat at this point! I can hook up everything and even jumper across the t-stat terminals and the heater comes on…but put the cover on (and MAN that’s a fiddlylittle prong setup!) and she clicks but no cigar. I guess for one last test I could gator clip wire from the wall plate to the thermo body and turn it on just to eliminate prong/clip connection problems. Surely the Luxpro digital 2 wire is rated to work this and I’ve just got a lemon….Thanks for all the help!

[rubicon327]

Originally Posted by Tford

Well, it’s the thermostat at this point! I can hook up everything and even jumper across the t-stat terminals and the heater comes on…but put the cover on (and MAN that’s a fiddlylittle prong setup!) and she clicks but no cigar. I guess for one last test I could gator clip wire from the wall plate to the thermo body and turn it on just to eliminate prong/clip connection problems. Surely the Luxpro digital 2 wire is rated to work this and I’ve just got a lemon….Thanks for all the help!

Happy to help. That thermostat is perfect for the application and I've made them work with Atwood/Suburban furnaces in several trailers. Sounds like you are close to having this figured out.

[Tford]

Another Luxpro coming as a warranty replacement..

[rubicon327]

Just another thought...
Is there a reset button inside the thermostat? If so, it can't hurt to try pressing. From what I see online if this is held for 5 seconds it should reset. Might want to contact LUX though because there is nothing specific in the instructions about this.
1.856.234.8803 or techsupport@luxproducts.com

[Tford]

Wow! Sterling customer service from Supply House, new replacement Luxpro thermostat arrived TODAY and there’s HEAT in the 5.0!! Many thanks to Dave and Gus here at the forum. A priceless resource!