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furnace won't stay on - Burnham gas FHW

EdStauff Member Posts: 2
Forgive terseness; posting from smartphone.

Have Burnham P204A-WNI with Honeywell components: R8285D control center, S86H intermittent pilot; can't see model #'s on the rest, but specs claim L4080B /L4006A hi-limit control, VR844P / VR8440P gas valve, Q348A pilot. Age unknown.

Working fine til power lost Saturday. Now on generator; wouldn't start til I disconnected thermostat (Lux 1500 programmable, 2-wire) and joined wires together to fake a call for heat. Seemed to run fine for a while (an hour or so?), then stopped and didn't come on again. Shut off gas & power, waited about 10 minutes, then turned on gas and then power. Came right on, sounded normal, flames looked healthy. After 1 or 2 minutes, it shut down and didn't come on again. House temp is in the low 50's. Can't afford a service call. Have searched web, studied manuals; don't know what to try next. Did realize that I failed to get generator power to 24v transformer for thermostat, but therm. is still disconnected from furnace, with wires to furnace twisted together w/ wire nut.


  • Tim McElwain
    Tim McElwain Member Posts: 4,628
    Some controls

    will not function correctly on generator power. There has to be an interface for proper operation . I am on the way out the door but suggest you call the company that makes the generator and they should be able to assist you.
  • EdStauff
    EdStauff Member Posts: 2
    which control

    When you wrote "some controls", did you mean the external thermostat (Lux) or the internal control center (Honeywell R8285D)?

    Regarding "there has to be an interface": I thought that with a 2-wire 24v thermostat, the 2 wires served as a simple on/off switch for the furnace, controlled by the thermostat, and therefore replacing the therm. with a wire should cause the furnace to run constantly. Am I misunderstanding something?

    Thanks for the help!
  • John Mills_5
    John Mills_5 Member Posts: 952
    Quality of AC

    The ignition control uses flame rectification to know that the pilot is on so the main burner can come on. This is basically looking for a DC micro amp current passing through the flame. This requires a good clean AC signal coming in. There has been problems with generators not producing a good AC supply and therefore not working well with heating equipment. 
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