Re: Furnace Problems
First of all, what make is your furnace? They all work pretty much the same but there are significant differences. The most common cause of a furnace blowing but not lighting the flame is what is called the "sail switch" not closing. The sail switch is a switch that is closed by a movable vane in the air path from the blower that moves the air through the furnace. That blower is actually two blowers on opposite ends of one motor shaft, one providing combustion air from the outside and the other moving the air from the inside of the RV through the heat exchanger to heat the interior of the RV.
The sail switch is a safety device to prevent the opening of the propane valve if there is not enough air movement. There are many different things that can cause it not to close. Were you plugged into shore power when the furnace failed? If not, try it when you are plugged to shore power to see if it works. Low battery voltage will cause the blower to turn more slowly and that can cause the sail switch not to close, thus you get blower, but no heat.