HydraFlame 8500-II Issues
Working on a 27 y/o MH a homeless Vet lives in. I'm a retired EE so I know my way around a DMM. ;) This time it's the furnace that suddenly quit - fan wont even come on anymore. He attached the two w...
Forum Discussion
The owner's manual I have for our 8500 II might be on-line but all I can find is for the IV. I didn't check to see if it is similar.
Yes, check inside the thermostat. The off switch matters! However if the furnace was working and then didn't, it could be several things. A fuse, a circuit breaker, the blower relay, etc.
I can't tell which thing is which, but some of the things don't come on till others do so I don't think a meter can tell much if the voltages are right unless it is running? I don't know.
The thermostat gets the blower relay going after a time delay up to a minute, and that gets the sail switch to close once there is enough blow, and that energizes the DSI Board, which has a 20 second delay for a furnace purge, then the gas valve opens, and an ignition spark. If no flame after a few seconds of sparking, the DSI Board shuts off the gas valve. There is a limit switch to shut it down if it all gets too hot --like from an air circulation restriction (like wasp nests in the exhaust?).
Yes, check inside the thermostat. The off switch matters! However if the furnace was working and then didn't, it could be several things. A fuse, a circuit breaker, the blower relay, etc.
I can't tell which thing is which, but some of the things don't come on till others do so I don't think a meter can tell much if the voltages are right unless it is running? I don't know.
The thermostat gets the blower relay going after a time delay up to a minute, and that gets the sail switch to close once there is enough blow, and that energizes the DSI Board, which has a 20 second delay for a furnace purge, then the gas valve opens, and an ignition spark. If no flame after a few seconds of sparking, the DSI Board shuts off the gas valve. There is a limit switch to shut it down if it all gets too hot --like from an air circulation restriction (like wasp nests in the exhaust?).
