We tried the furnace on our '79 31ft Sovereign
(a Suburban, haven't figured out what model yet). It took a little while for it to start the first time, but now it starts beautifully (it's got an electrostatic ignition system). Turning up the thermostat turns the fan on immediately, and after a few seconds, the furnace lights up. All that is very nice. The flame is mostly blue at the bottom, some yellow at the top.
After about 30 minutes or so, I started hearing "thwoomp" sounds. I took off the cover, and saw that the flame would turn erratic, and, scarily, would leak out through the right side of the metal plate which contains the electrodes and the glass covered viewing hole (a fraction of an inch, but still). The gasket-like material on that plate looks very old and crumbly, so I'm not too surprised that flames _can_ leak out of there, but I don't understand why the flame is irregular.
Naturally, as soon as that happened, I turned off the furnace. I tried a few minutes later, with the same results.
I don't know much about the history of the furnace, but the trailer came with a suburban control board in a cardboard box, which, I'd guess is either the original control board that was replaced, or a replacement control board which was never installed. I _think_ my RV mechanic checked out the furnace when he gave it a once over, but it was july and I wasn't thinking much about furnaces then.
The propane tanks have new regulators and have just been recertified. I've never noticed any variation in LPG pressure on the stove.
What kinds of things could cause the gas mixture to get so out of whack after a while?
I was already planning to 1) get a CO detector, 2) clean out the furnace, since I don't know what state it's in inside. Is there a post somewhere with detailed instructions on how to clean these furnaces? I've heard about forcing air through,but I'm a little puzzled as to the exact steps.
I'd also like to replace the gasket around the electrode-bearing plate. Where should I look for that, and what is it called?
Thanks for any help!
PS: the airstream is in a remote location (as in, no road or car-ferry!), so "taking it in" is quite a hard and expensive operation. I'd like to fix it myself if possible...