Furnace question

[createdtomove]

We're camping and my furnace has been hit or miss. In the middle of the night when I go to turn it on, it blows cold but won't ignite, even with full battery. If I plugin the generator it'll fire up. When I've played with it during the day it seems to work fine on battery, but not in the cold. It's just not consistently bad but is having issues.

When it fails to ignite and is blowing cold it'll stop and a red light blinks once every 3 ish seconds.

 

[JimD]

Best guess it is the sail switch which is there to sense air flow. Firing up the generator will send a charge voltage to the battery which increases the voltage level a bit and probably makes the blower motor spin a tad faster. That little extra speed apparently is what gives it enough air flow to activate the sail switch and allow operation.

Verify the intake and out ducts are clean. Find the sail switch, which is a little flappy piece of metal (maybe plastic) that moves with air flow. Make sure it moves freely. Also make sure the switch the sail activates is not gummed up causing it to not actuate easily. My son had a sail switch, which was a pushbutton switch in his unit, that was hard to depress. A shot of WD40 solved his problem.