Wall Furnace Mystery

Discussion in 'HVAC Heating & Cooling' started by Mike Armstrong, Nov 5, 2009.

  1. Mike Armstrong

    Mike Armstrong New Member

    Aug 28, 2008
    I have an approx. 15y/o Williams Furnace Co. gas wall furnace model 6508532. Over the past year my furnace would occasionally not come on. I would check the pilot and sure enough it would be out. After relighting the pilot it would fire up and run as normal. Sometimes after waiting awhile I would hear a click like a valve opening/closing. I would relight the pilot and the furnace would come on. After awhile the furnace would not come even though the pilot was lit. Then out of the blue it would come on normally. I thought it might be the thermostat because I could connect the two wires going to it and the furnace would come on. after replacing the thermostat the same problem started again.

    I read on the net that it might be the thermalcoupler so I replaced that and the problem remains. When the pilot is lit and I disconnect the thermalcoupler the pilot shuts off. Whenever I shut the gas off to the furnace after awhile I hear that same valve opening/closing.

    Now, though the pilot is lit the furnace will not run at all. It's been a few days and I'm out of guesses. Is it time to replace the whole main 'valve module'? I'm about to try and find one on the net and do it myself but before I do I was hoping to get some answers here. Thanks

    This is what my furnace looks like though it doesn't have 'Forsaire' on it.


    Last edited: Nov 5, 2009
  2. hj

    hj Moderator & Master Plumber Staff Member

    Aug 31, 2004
    Cave Creek, Arizona

    It is probably a "powerpile" system. If so, loosen ALL the connections and retighten them because even a slight amount of corrosion can keep it from working.
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  4. Mike Armstrong

    Mike Armstrong New Member

    Aug 28, 2008
    Thanks HJ, I'll try that.

    It's strange because the heater looks and runs like new. When I've had this problem with it in the past, out of the blue, for what seems like no reason, it would start working fine again. I've always thought that as long as it actually 'works' then it's not actually 'broken'. There's just something loose, out of align or slightly out of adjustment.

    We'll see, thanks.
  5. Lakee911

    Lakee911 I&C Engineer (mostly WWTP)

    Aug 23, 2005
    I&C Engineer (mostly WWTP)
    Columbus, OH
    Most likely loose connection or corrosion. I would have suspected thermocouple as well. Try new gas valve if that doesn't work.
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