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Yes, this is a 45 year old, but still very dependable and functional boiler type furnace.
The gas valve is a Honeywell VS8279A1034 1/2" X3/4" RATED 1/2 PSI FOR G-LP. With the standard Honeywell VS8002A Control.
The four contact wiring on it has only a very simple 2-wire aquastat connected to the two top contacts, a two -wire thermopile wired to the two bottom contacts, and a two wire thermostat wired to the two left most contacts (one of the top and one of the bottom contacts).
It's hard to believe that anything would go wrong with this essentially untouched gas valve. I believe that it is just failing to easily reset after the pilot blew out from a backdraft or similar cause. I had the flames on the burner turned way down to just above the lowest setting , just a notch above where the pilot actually lights the burners. This is in a dry basement of approximately 1200 sq. ft., with a 50 gallon gas fired hot water heater about two feet away. Adequate ventillation, good oxygenated air,and no breezes. The water heater is burning fine just two feet away. So good gas pressure. The igniter flame lights easily and has a good color flame and the flame touches the top 3/8" of the thermopile like it should. It just seems like the valve won't activate and allow gas through the 1/8" pilot tubing. And I have already cleaned and checked the pilot tubing for any obstructions, of which there were none. Know of any TRICKS to get the millivolt Honeywell gas valve to reset/open to allow gas through the 1/8" pilot tube ? The valve already lets gas through the 1/4" igniter tube right next to the pilot.