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Heatilator Will Not Turn On (Pilot Lit) -- What is minimum mV from Therompile?

Post in 'It's a Gas!' started by jj911c2, Dec 21, 2008.

  1. jj911c2

    jj911c2 New Member

    Joined:
    Dec 21, 2008
    Messages:
    3
    Loc:
    Seattle, WA
    I have a Heatilator GNBC30 that will not light via the wall switch. The pilot is lit and stays on fine. I also bypassed the swtich for troubleshooting and that was not the issue.

    From another post I saw to test the mV coming out of the thermopile. I get 250mV from the Thermopile - is this too low? I am trying to determine if I should replace the thermopile or if it is somethign else.

    The fireplace started out with a delay when the switch was thrown (a few minutes) and now will not turn on at all.

    Thank you

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  2. jtp10181

    jtp10181 Minister of Fire

    Joined:
    Feb 26, 2007
    Messages:
    3,724
    Loc:
    Madison, WI
    Is it 250 standing or with a load (switch on)?
  3. jj911c2

    jj911c2 New Member

    Joined:
    Dec 21, 2008
    Messages:
    3
    Loc:
    Seattle, WA
    Thanks for quick response.

    250mV with switch off

    118mV with switch on (but fireplace not on -- only pilot)
  4. jtp10181

    jtp10181 Minister of Fire

    Joined:
    Feb 26, 2007
    Messages:
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    Loc:
    Madison, WI
    First check the pilot flame, make sure it is nice and string and stable. If it looks lazy you need to clean out the inside of it and the orifice. Check mV again and see if it goes up. Also disconnect the thermopile from the valve and check the mV that way also. If that doesn't work you could probably just replace the thermopile. Although if the pilot assembly is 5 years + old I would just replace the whole thing. Its usually only a few extra $$ to do that over replacing the thermopile and thermocouple. Usually when one goes the other is not far behind. You should be getting 500+ mV off and 220-250 mV while turned on.
  5. DAKSY

    DAKSY Patriot Guard Rider Staff Member

    Joined:
    Dec 2, 2008
    Messages:
    5,012
    Loc:
    Averill Park, NY, on Burden Lake II...
    Replace the T-P...
    You should get around 550mv from the pilot - burner off...
    220 +/- with the burner on...
    You're down around 1/2 of what you need...
    If you can't get a heatilator or HeatnGlo
    True Value has a universal type for about $50 that'll prolly work...
  6. jj911c2

    jj911c2 New Member

    Joined:
    Dec 21, 2008
    Messages:
    3
    Loc:
    Seattle, WA
    Thanks again for the follow up.

    I took it appart and cleaned it up (it was pretty clean to start with) but am still getting the same readings. Pilot flame hits the TP pretty well.

    There is a Heatilator dealer in my area I will try to get a new one from.

    There is a red caulk that the wires run through i need to remove and replace - what type of caulk is that?
  7. DAKSY

    DAKSY Patriot Guard Rider Staff Member

    Joined:
    Dec 2, 2008
    Messages:
    5,012
    Loc:
    Averill Park, NY, on Burden Lake II...
    Hi-temp RTV Silicone.
    You can grab a small squeeze tube for about $7...
    Color doesn't matter...
    Some units actually use an RTV grommet
  8. Bobbyc

    Bobbyc New Member

    Joined:
    Nov 12, 2012
    Messages:
    1
    I did all of the above and am getting 520 mV at the valve and switch but still the fireplace will not fire. I also jumpered the leads at the valve and still it would not fire.
  9. FanMan

    FanMan Feeling the Heat

    Joined:
    Mar 4, 2012
    Messages:
    313
    Loc:
    CT stix & upstate NY
    Holy thread necrophilia Batman!

    Perhaps you should start a new thread with information on your own problem rather than resurrecting a four year old topic... otherwise you'll just confuse people...
  10. DAKSY

    DAKSY Patriot Guard Rider Staff Member

    Joined:
    Dec 2, 2008
    Messages:
    5,012
    Loc:
    Averill Park, NY, on Burden Lake II...
    Is the "ON-PILOT-OFF" knob in the "ON" position? What unit are we talking about?

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