atwood furnace model 8535 ran out of propane, won't restart now

[rewaters49]

My 2003 Fleetwood Bounder has the Atwood 8535 IV DCLP furnace. I have an Extend-A-Stay installed. Yesterday the furnace ran properly with a 20 lb. grill tank connected and the valve to the coach tank turned off.

Last night it seemed like it was just running and running, so I turned the thermostat down and the furnace shut off. When I turned it up again, I heard a click from inside the electrical control panel that has all the breakers and fuses, but no fan and no heat.

I figured, and found, that the grill tank was empty. I turned on the valve to the coach tank. I took out the empty grill tank and connected a full one. My stove and oven work fine, so I have gas available. I still hear the click from inside the control panel when I move the thermostat up or down, but no blower fan, no heat.

I turned it off and back on several times. No help. I checked every breaker and every 12-volt fuse. They're fine. Still get only a click. I pulled the cover off the outside of the furnace. There is a switch on the motor housing. I turned it off, then back on. No help. Next to the switch is what I think is some sort of breaker. It has a button which I think would pop out if tripped, but the button is not out.

Is there a fuse somewhere in the thermostat? Is there a fuse somewhere on the control board? (I didn't see one, but it was dark and cold out there last night). Is there some 'lockout' switch I need to reset? Any help and/or advice would be greatly appreciated. Thanks.

[davecampbell]

Probably (probably..) need to bleed the furnace LP line. The cook-stove, when the valve is opened, just lets LP flow unimpeded, except for the knob setting which determines flow.

The furnace (all furnaces in general) has/have a gas valve that is electrically controlled, they dont just turn on and run for safety reasons. The valve may not open without a standing pilot,or, if a computerized high efficiency model, will lockout if it cannot prove a flame. May have to bleed the system. I dont know how that works on your furnace and dont recommend messing with a gas valve unless you know exactly what youre doing. Check the owners manual for a bleed procedure. Sometimes its as simple as manually holding the pilot light control down.

[rewaters49]

Dave, Thanks for your suggestion. I had already called a mobile RV repair guy. What he found was two loose crimp connectors that connect the control board and the fan blower motor. These are plastic connectors with a blade that is supposed to cut through the insulation and connect to the wire inside when you pinch them shut with pliers. In theory they're fast and cheap connectors. In my 7 year old coach in 12 degree weather they shrunk and thereby disconnected my furnace blower motor, so the furnace would not work. As soon as the crimp connectors were cut out and proper wire splices made, everything worked just fine.

[davecampbell]

I wont use those quick connects, theyre junk. Good that you have heat!

Just odd that it coincided with running out of propane.

[Midniteoyl]

Quote:

Just odd that it coincided with running out of propane.

Actually it coincided with him turning it off/on...

[rewaters49]

The mobile RV tech said running out of gas produces a hard lockout. Normally turning the furnace off and back on will reset it, but not always. Disconnecting the small wiring harness from the control board (easy to do on my particular model furnace) will definitely reset the board. It's really hard to say now exactly what happened and in what order. The loose crimp connectors were definitely affected by the cold. I will NOT use them for anything as critical as the furnace. And if I find any more of them I intend to replace them. But it sure is good to have heat again!

["007"]

If you have air in line as dave said it will take a few dry starts to get gas back to the furnace.
Switching tanks may have place air in lines also.
Make sure the shut off for gas furnace is on.