Got tired of typing this so saved it as a text file....
When the T-Stat calls for heat the control board starts the blower (1)
The blower blows closing the sail switch (2)
The control board then opens the gas valve (3) and begins sparking (4.1)
Gas Flows (5) And ignitets (4.2)
The flame heats the flame sensor (5)
The flame sensor sends .480 volts to the control board (6)
which then detects the .480 and continues operation (*)
When the T-stat says "Enough already" (RV is now warm)
The control board shuts off the gas flow (*)
and then turns off the blower after a cool down (*)
*: At nearly every step the control board is involved. IF IT IS BAD, things will not work.. I recommend replacement boards from Dinosaur boards.. When Mine went out the Dino board was less than half the price and when opened the box the quality of construction and workmanship, and then design was very clear to my trained eyes.
1: No 12 volt to furnace, blower motor shot
2: Low 12 volt, air ducts clogged, blower "obstructed" bad sail switch
3: Bad solenoid, Clogged Gas Jet
4: .1: Bad ignition circuit (high voltage) on control board. .2: Points too wide (Very common it seems)
5: These do not often fail but they can
5: Bad connection, NOTE:
5 and * Bad wire.
* applies to all steps by the way So does bad wire/connection.
The switch tells the board that the Inducer motor is running and to light up the igniterIf it has a sail switch it's either the switch sticking,or the Inducer motor,,,,
Without it the igniter will not Come on,,,,The switch tells the board that the Inducer motor is running and to light up the igniter
Thanks. Lot of helpful infoHope that you recover from the flu quickly and get back to hunting soon.
A couple more references that will hopefully be helpful.
http://www.rverscorner.com/furnace1.html
http://www.rvforum.net/miscfiles/Furnace_Trouble-2.pdf
Page 6 of the second reference covers your case - blower comes on but no heat (ignition).
I do NOT have an RV, just googled info in the hope that it will guide you in troubleshooting.
Good luck !!!
If it has a sail switch it's either the switch sticking,or the Inducer motor,,,,
When you get back to it you should grab some pic's,,,,how old is the unit,,,,pull the cover and take some pics,,,,check for a birds nest in the exhaust,,,,