Furnace fan works but no heat

[Ben10281]

Here is a link to a manual for the heaters. Page 7 explains the sail switch in detail.

Suburban Propane Heater Manual

Unfortunately, for your model, you might have to remove the front cover(which is covered by one of your ducts) to see the flame. I don't have the version with the ducts just the direct blower to inside my van.

[Ben10281]

Here are some pics of the sight glass on my heater. The circle in the middle of the rusted plate above the igniter is the sight glass.

I am thinking that possibly if you removed the front cover to your unit, you would see a similar view to this.



Close up:



In this one you see that the burner sits behind the sight glass.



A little blurry, but this is what mine looks like when the flame is lit:

[Makalu1]

I had to wait until the temp outside got under 90 degrees so the furnace would fire up!

The van has sat unplugged for almost a week charging almost nothing on solar power. I turned on propane, turned on thermostat to high, heard the thermostat click once, then heard the blower come on, then several seconds later heard the click of the ignition and a faint sound of the furnace, confirmed moments later by heat coming out of both somewhat squashed ducts under the seat. It worked this time just like you all are describing and took under a minute to cycle on. As to what's with these two wires hanging out there and why it doesn't work the other half of the time, I am going to check out the manual first. Thanks for that!

[Makalu1]

Well this is a bit confusing...

[dhally]

Low battery voltage will cause this symptom. The fan has to provide a certain minimum air flow for safe combustion (as measured by the sail switch). If battery voltage is low, the fan runs slower and the air flow is reduced, and the controller won't allow the gas valve to open.