I recently changed over to the reserve cylinder when I had the other 30 lb. propane cylinder refilled. Now my furnace, Atwood Hydro Flame 8531-IV-DCLP, will not start. When I turn it on, using the thermostat, nothing happens. The blower does not run as it normally did prior to the furnace lighting. I have tried switching cylinders. My Atwood Hot Water heater is working & I can use the Atwood propane range.I have 12.4 volts through the off/on switch & the circuit breaker. The fan will run if I jumper this to the motor. There is also 12 volts from the thermostat and the ground wires all check out.All web troubleshooting articles refer to a "relay" with four terminals. My unit does not have this, only the circuit board. Where is this relay? Also I get no light or flashes of the circuit board LED.Any and all help is greatly appreciated. Thanks!

The 'timed delay relay' is part of your ignition control board.Some models it is a stand alone relay......power from ON/OFF switch/CB went to the relay and then to blower motor AFTER power come from T-stat that energized a coil which when heated made up path in relay for power to blower motor.You have power to board and power from T-stat....blower runs when you jumper power.Bad ignition control board OR bad connections/ground on board.Replacement board......Dinosaur Board LINKAtwood 8500 Series Manual (Limited but has wiring & part numbers) LINKAtwood 79/80, 85 & 89 Series Manual....more info with troubleshooting LINK

Did you turn the thermostat off and then back on? Not just sliding the temp adjustment down....but switching it off and then back on. Typically they will try to ignite 3 times and then shut down. Have to turn off and on to reset. Propane would have nothing to do with the furnace not even coming on again.

Moved from Forum Technical Support

My guess is that the furnace stopped working, and then you tried changing the cylinders, and then found it is still not working. So why did it break? If the fan is not coming on, the two logical things to check are +12 to the furnace. The second is the thermostat letting +12 volts go to the furnace to tell it to start? A blown fuse in either location can prevent this. If you know about wiring, then pull off the thermostat, and short the red and white wires. If the furnace starts, the the thermostat is probably the problem. If it does not start, then it can still be a blown fuse to anything, or another problem. You said the fan works while +12 is applied to it, so I am going to say it is most likely that the thermostat is the problem. Connecting the red and white wires might start the furnace, and prove the thermostat is not working. Fred.

Check and make sure the propane cylinder has propane first. Then see if you can get the stove to light. If not, close the propane valve, remove the hose. Re-install the hose, slowly open the valve. Opening the valve to quickly can trip the OPD, ( Overflow Protection Device ) causing no flow of gas. Go back and light the stove, this may take a bit of time to bleed any air from the lines. Use a match or one of those butane lighters instead of the ignitor on the stove. When you get a solid steady flame, try the furnace. It should light, it may take a couple of tries to bleed any air.

Atwood RV Furnace will not start after changing propane cyl

19 Replies

PJ4284
Explorer
Apr 29, 2019
This maybe a really dumb question. Do I have to have the battery hooked up or a good battery for the furnace to run even when the camper is plugged in?
PJ4284
Explorer
Apr 29, 2019
dougrainer wrote:
The BLUE wires just send a 12 volt signal to the furnace to ACTIVATE the furnace to heat. Once the Blue wire sends the 12 volt signal the Fan relay is energized and the motor should come ON. NOTHING will happen until the Fam motor runs. So, you need to jump the 2 blue wires AT the furnace, not at the Tstat. Also, ONE of those blue wires must have 12 volts positive. So, IF you have no 12 volts at either BLUE wires that is the start of your problem. The blue wires start at your furnace and the Furnace supplies one of those Blue wires with the required 12 volts. It makes no difference which blue wire has the 12 volt power, just one of them. Doug

Hey Doug, Thanks. I did connect the 2 blue wires at the motor. I put in parentheses Tstat because I was told the 2 blue wires at the motor called it system to heat and the motor would kick on. Anyways, After connecting the 2 blue wires nothing happened. One blue does have 12 volts. When I take the red wire to fan motor and connect it to the same terminal (as the blue that has 12 volts) on the relay the fan will kick on but I do not hear any clicking like it wants to ignite. When I put the red back on the relay where it is suppose to go and reset everything nothing happens. Of course I do not have the propane on at this point.
wa8yxm
Explorer III
Apr 29, 2019
Regarding that 6300.. I'd consider upgrading the "Electronics" part to a Progressive Dynamics 4600.. it's a Bolt in replacement for that part.

From time to time we speak of some very bad converters that can among other things damage your battery..... Not sure if the Parallex 6300 is. but Parallex bought out Magnatek and their 6300 was. and you did a fairly good job of describing the Magnatek 6300 (Unfiltered and battery circuits)

This likely has nothign to do with the furnace. but it will improve battery life.
dougrainer
Nomad
Apr 29, 2019
The BLUE wires just send a 12 volt signal to the furnace to ACTIVATE the furnace to heat. Once the Blue wire sends the 12 volt signal the Fan relay is energized and the motor should come ON. NOTHING will happen until the Fam motor runs. So, you need to jump the 2 blue wires AT the furnace, not at the Tstat. Also, ONE of those blue wires must have 12 volts positive. So, IF you have no 12 volts at either BLUE wires that is the start of your problem. The blue wires start at your furnace and the Furnace supplies one of those Blue wires with the required 12 volts. It makes no difference which blue wire has the 12 volt power, just one of them. Doug
PJ4284
Explorer
Apr 29, 2019
Ok I am curious. I have the same issue with an Atwood 8520-IV. I bought a new Thermostat, time relay and had the board tested. Fuses are good, Breaker is good. All are functional. When I turn the thermostat on the blower motor will not turn on. When I connect the 2 blue wires at motor(Thermostat) the motor will not turn on. When I connect the red (motor) and Black(motor) or bypass them to a battery the motor turns on and blows strongly. Now, I have power to the manual on/off switch. Power to the relay through blue wire but nothing past that. I am curious as to what wires do I check or what wire was crimped badly on the other guys? Any help would be greatly appreciated. BTW, I was told by the service dept at a dealer if I connect the 2 blue ( thermostat ) at motor the fan-blower should kick on if it doesn't its a wire issue. Where do I start?
Sodakdave
Explorer
Apr 11, 2018
Thanks SoundGuy. I had noticed the thread was old but figured it was worth throwing out there. The good news is that I was able to resolve the issue (bad crimp on a connector). Thanks anyway.
SoundGuy
Explorer
Apr 10, 2018
Sodakdave wrote:
Was this ever resolved? I have the exact same issue.

This thread is over 5 yrs old and the OP no longer has any posts showing as active. Probably hasn't been around for a l-o-n-g time so I wouldn't hold your breath waiting for a response.
Sodakdave
Explorer
Apr 10, 2018
Was this ever resolved? I have the exact same issue. I was on a spare LP tank then switched back over to my main tank. Now the furnace will not light (fan does not clear the chamber, nothing happens). I am able to jumper to run the fan so we know the motor is working and power is making it to the furnace. I tried jumping the two blue (thermostat) wires and even after waiting for the delay, nothing happens. I gave up and assumed the board had gone bad so i ordered a new board and still nothing happens.
John_Joey
Explorer
Oct 20, 2013
Golden_HVAC wrote:
My guess is that the furnace stopped working, and then you tried changing the cylinders, and then found it is still not working...

That was my first thought also. Changing propane cyl and then no fan simply do not go together.

Now if I assume it didn't work prior to the change, and the furnace was being look at by someone, then I might also assume that the rocker switch for the fan may have been thrown, and left in the off position.
dgcarlson
Explorer
Oct 20, 2013
Atwood HydroFlame 7900, blower starts, but intermittently the ignition will not "click". I was able to start the burner by slapping the inside of the air duct, so I'm thinking it's a sticky airflow switch. AGain, once the ignition clicks a few times, the gas will always ignite and heat starts. The blower needs to be up to a certain RPM at the start to close the airflow switch, before the gas valve opens and ignition starts. Comments?