Furnace issue

[cavaughan]

So I have just over a year old Escape. The furnace in it, as I'm almost certain, works on electricity and gas. In fact, last year when hooked up to external power, I know I just turned the furnace on (gas was off) and it heated the RV.
Recently, we went on a trip off-grid. When I tried using the furnace one cold morning, it just clicked several times and then gave up. The odd thing is after coming home, I removed the outside cover, blew out some needles, tried it and it worked on gas fine. So maybe it was just the needles causing an issue.
Last night, at home while on power, I tried it out (gas completely off) and it did the old clicking a few times and silent. Retried many times. Kept checking electrical, but everything seemed fine.
So any clues about what might be going on? I looked at the docs for the furnace from dometic(?) and they also show it working on gas/electrical, although they mention some switch somewhere. I know when I removed the outside cover (which requires special screw heads) that there was no switch right inside.

 

[jjdeluca]

The furnace has an electronic ignition but operates on propane. So with the gas turned off, you're hearing the ignition attempting to ignite the burner but with no fuel to burn. If you turn the gas back on it should (hopefully) work fine.
(Not sure how it worked last year on shore power with the gas off though)

 

[7Gentex]

Maybe................??

The "furnace" works by burning propane as described above. If the gas is turned off the furnace will not light.......

Though you may have an electric "heat strip" integrated into your air conditioner, if you have an air conditioner. The electric heat strip is an option. No propane required, just 120volt electric. Selected via the thermostat. Or, you may have a "heat pump" air conditioner which also provides heat without propane. Same for control / selection I believe via the thermostat.

Which air conditioner (if any) brand / model do you have?

 

[SRS]

So I have just over a year old Escape. The furnace in it, as I'm almost certain, works on electricity and gas. In fact, last year when hooked up to external power, I know I just turned the furnace on (gas was off) and it heated the RV.
Recently, we went on a trip off-grid. When I tried using the furnace one cold morning, it just clicked several times and then gave up. The odd thing is after coming home, I removed the outside cover, blew out some needles, tried it and it worked on gas fine. So maybe it was just the needles causing an issue.
Last night, at home while on power, I tried it out (gas completely off) and it did the old clicking a few times and silent. Retried many times. Kept checking electrical, but everything seemed fine.
So any clues about what might be going on? I looked at the docs for the furnace from dometic(?) and they also show it working on gas/electrical, although they mention some switch somewhere. I know when I removed the outside cover (which requires special screw heads) that there was no switch right inside.

Possibly a minor point here, but the furnace does use 12VDC to run the blower in addition to the direct spark ignition. Burning propane provides the heat.
If your running the furnace on battery power only, the blower may not be running at sufficient speed to close the sail switch. There are other factors that can restrict air flow and fail to close the sail switch.
When you were plugged into shore power, the batteries were being charged and the converter's 12 volts probably gave the blower sufficient boost to close the sail switch.
That's my theory For what it's worth.

 

[brroberts]

Possibly a minor point here, but the furnace does use 12VDC to run the blower in addition to the direct spark ignition. Burning propane provides the heat.
If your running the furnace on battery power only, the blower may not be running at sufficient speed to close the sail switch. There are other factors that can restrict air flow and fail to close the sail switch.
When you were plugged into shore power, the batteries were being charged and the converter's 12 volts probably gave the blower sufficient boost to close the sail switch.
That's my theory For what it's worth.

This ended up being my main issue. I solved it with a buck boost. Described in the attached PDF.

 

[7Gentex]

Maybe #2

................ I know I just turned the furnace on (gas was off) and it heated the RV. ............

I looked at the docs for the furnace from dometic(?) and they also show it working on gas/electrical, although they mention some switch somewhere.

#1 - if the propane was turned off (both tanks), and you got heat, you either have an electric strip in your air conditioner, or a heat pump air conditioner.

#2 - believe you are confusing the water heater electric option (switch is outside under water heater cover) with the furnace?