RV furnace trouble shooting

[bwtrout]

The blower motor went out in my RV furnance (Hydro Flame Excalibur-II 8531-II) I pulled the furnace, replaced the motor, burner assembly, 10amp circuit breaker, thermostat, inspected, cleaned up contacts and reinstalled. I figured I would have some air in the line so I didn't expect it to light on the first couple tries.

The problem is: I turn on the thermostat raise the heat setting, the blower comes on for the purge cycle, I hear the ignition sparking (clicks) for 6-9 seconds the fan continues to run but it never lights. I also smell no gas at the vent.

Will the igniter still spark even if the sail switch or limit switch is bad?

[Ryan Berger]

make sure you blead the lines for a good 30 seconds,, either by holding down the pilot button or taking the hex screw out of the gas valve till you smell gas, without looking at the furnace I would say it should not try to light if the sail switch or limit switch is out,, take a resistance reading accross the whole safety circut and see if there is resistance,, if it reads OL you will need to then search for the open saftey

[bwtrout]

I'll give that a try.

Should I be able to hear the gas control valve open and close?

[Dogzlife000]

Not sure if you would hear the main valve open or not.

What I would try is to attempt to start the furnace, wait about 15 seconds for the purge cycle, and test for voltage at the main valve. If no voltage there, check voltage on both sides of the limit switch. (Current flows from the relay, to the sail switch, to the limit switch, to the main valve)

If you need a service manual, post an email address and I will send you one.

Pete

[bwtrout]

Thanks guys for all the help!!! I got it going this last weekend. I ended up checking for voltage to the gas valve and it was good so I replugged them in (it could have been that I had the male plug outside the female plugs housing ) and purged the line (it did take a while to smell the LP gas additive) When I tried it again it worked