Atwood Hydroflame 8531-IV Not Cycling

[RamblinAnne]

Hey friends- hoping someone can help with this. I am having an issue with my Hydroflame 8531-IV furnace on my Bigfoot truck camper. I turn it on and heater kicks up and starts heating no problem. Runs for a good long while until it comes to temp without any issues. Once it comes to temp, it cycles off as normal. However, after the temp drops back down, the heater never cycles back on again. If I turn the heater off then back on manually, it’ll come back on but never automatically as it’s supposed to. I took the furnace apart and inspected the sail switch. It was not dirty and appeared to be in working order. The circuit board shows a steady green light which signifies that it’s not an airflow issue. Does anyone have any idea what may be causing this?

[RamblinAnne]

Oh gosh you guys. After taking apart the entire furnace and thermostat and inspecting every little piece, it turned out to be a loose wire connection. One of the ones that goes in the bundle plug that you access from the inside of the camper (under the dinette). Thanks so much for your input and hopefully this can help someone else solve a similar issue, as I see several posts about it with no conclusion.

[notsobigjoe]

thermostat.

Sorry, missed where it didn't work.

[ticki2]

When you have this problem are you on shore power or battery power or doesn’t it matter ?

[anutami]

I had a similar issue a couple days ago while camping in temps below 10 degrees F. Since my batteries are located in an outside compartment they got so cold they started showing such low voltage my furnace failed to start back up. I hooked up my Honda genny and it solved the issue.

[enblethen]

Locate the thermostat wires at the furnace. Should be two blue wires in furnace. connect them together. Furnace should come on, produce heat, separate the wires furnace should go onto cool down and shut off.
Depending on thermostat, you can tie thermostat wire together there. same thing should happen.
I agree that it could be thermostat.

[RamblinAnne]

RamblinAnne wrote:

Kayteg1 wrote:
Try to eliminate thermostat failure by jumping the wires.

okay! Not exactly sure what jumping the wires means but I just took my multimeter to it and when the furnace is off, I have a solid 13+ V going to it. When I turn it on however, it drops down to 0.01 volts and keeps slowly dropping off. Is this a thermostat failure or a wiring issue?

Sorry should have been more clear- when the thermostat is switched OFF- steady 13+ volts. When the thermostat is switched ON but does not signal furnace to come on (because I have to wait awhile to be able to manually switch it off and on again) that’s when I see a drop off in voltage. When thermostat is switched ON and furnace is running, a solid 11+ volts.

[RamblinAnne]

Kayteg1 wrote:
Try to eliminate thermostat failure by jumping the wires.

okay I jumped the wires and it did not turn the furnace on. Bummer

[ticki2]

I suspect it is the thermostat . What make and model is the thermostat ? Before going too far check the thermostat wire connections at the thermostat and the furnace

[RamblinAnne]

Kayteg1 wrote:
Try to eliminate thermostat failure by jumping the wires.

okay! Not exactly sure what jumping the wires means but I just took my multimeter to it and when the furnace is off, I have a solid 13+ V going to it. When I turn it on however, it drops down to 0.01 volts and keeps slowly dropping off. Is this a thermostat failure or a wiring issue?

[Kayteg1]

Try to eliminate thermostat failure by jumping the wires.