I tested the furnace in out '73 Tradewind, and it worked (sort of) but it would keep blowing itself out sometimes when the main burners came on, and always when they went out. If it didn't blow out, and stayed on, I had 3 or 4 of the main burner fins still burning at a low rate as well as the pilot. Not good! It was obviously leaking somewhere in the valve body.
I know these aren't supposed to be serviceable, but the parts aren't available anywhere, and a pro wouldn't touch it, so I did what I usually do .. try to fix it myself!
I opened the control valve and cleaned all of the diaphragms and surfaces in there and put it back together with a new gasket that I made from a gasket paste that was rated for propane. While I had the furnace apart I cleaned out the fist sized mud dauber nest around the heat exchanger.
Decided that one of the problems was that my pilot light was too weak, so I took it out, and apart, and cleaned the orifice using an MSR backpacking stove maintenance kit left over from the days we owned and operated a camping store. It has little hard wires for cleaning jets like that.
Got it back together and working great. Pilot stays lit, and it cycles on and off just fine.
My one stepson is in the middle of an HVAC course so I got him to talk the teacher into letting him bring home the C0 sniffer as a final test to make sure there were no leaks in the heat exchanger, or anywhere else.
He went over it with a fine tooth comb doing his best to find a problem! Did the soap solution thing everywhere there could have been a leak and everything! I think he wasn't real happy that I could just go ahead and do something that he had to go to school to learn! He would have loved
to find a problem that I missed!
Anyway, this unit was ticking away with between .000 to .001 ppm and well within the accepted range for combustion at the vent outside.
I guess there is still some life in it yet, and since we probably will use it maybe only once or twice in a year, it will do just fine. I can light the pilot a lot of times for what it would cost to replace it with one with electronic ignition! After all, it does
have a sparker s I don't even have to use matches!
I'll probably install a new thermostat because the old one in the Tradewind leaves too much of a gap in temp. between the set temp., and when it switches. I'll have to look into what might be compatible with the old furnace.