The hydroflame furnace in my 1967 Caravel
is wonderful...for awhile. But after about 15 minutes, it starts to make a louder roaring sound, the heating output drops, sometimes it goes out, then relights, cycles back and forth for awhile and after about an hour it settles into a pattern of roaring and the flame seems to move to the air inlet section of the burner (which is non adjustable) I assume that all this is an indication that I have too much or too little air entering the burner, and I assume it is too little and probably due to some blockage or clogging of the gravity air intake vents...am I on the right track here? If so, is there a way to clean the combustion air vent short of trying to separate the parts and remove the entire thing from the trailer?
I have taken the heater apart three times (not the vents though, which appear to be corroded together and not likely to dissassemble), cleaned and reassembled it and still the same issues....it works like a charm for awhile, then it goes crazy...any help or advice would be welcome.