Furnace problems! How do I fix?

Discussion in 'Homesteading Questions' started by cc-rider, Dec 17, 2003.

  1. cc-rider

    cc-rider Baroness of TisaWee Farm Supporter

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    Me again. :( Seems like I'm always asking for advice. Dunno what I did before I found this website! Thanks, all!

    I have a fireplace with natural gas logs (unvented) that I use to heat my upstairs. Three days ago, I noticed in the morning that the pilot had gone out during the night. Thought that was strange -- hasn't done that in the three years I've had it. No drafts or anything. I held in the "pilot" button, flicked the starter and it lit. Ran it awhile and it was fine and later shut down. (It is on a thermostat).

    Next morning, woke up cold and found the same thing. Ditto.

    Yesterday, same thing -- except I can't get it to stay lit at all now. I tried off and on yesterday and then resigned myself to putting the electric blanket on the bed and running an electric spaceheater :waa:

    If I push the "pilot" button, and flick the starter, it lights. So there is obviously gas getting through. I hold the pilot in for a long time, and as soon as I let up on the button, it goes out. I wouldn't think it was an oxygen sensor going bad because I doubt it would even let the pilot light be lit. What else is there that I can possibly replace?

    I really HATE to call a furnace guy -- it cost me a week's wages to have the shut-off valve and 6' of gas line run to the fireplace to start with!!

    Thanks for any advice you can offer!

    Chris in COLD Ohio
     
  2. Sounds like the thermocouple is bad. It is bulb like part that when lit the pilot light flame is in contact with it. It should be less than $10.00 at the local plunbing supply.

     

  3. JWH123

    JWH123 Well-Known Member

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    USA
    The thermocouple might be a culprit, since you've had the fire go out multiple times.

    http://hearth.com/what/gas/howgasworks.html

    One note though - on my ventless heater, if the thermocouple shuts down the unit, you are supposed to turn the gas control to 'Off', not just 'Pilot', and let it sit for a few minutes. Then turn to pilot, hold the button in, light, hold the button for 30 seconds, release button, then turn to 'On'.

    Try turning the control valve to Off and trying again.

    When you hold the button in you're bypassing the safety shutoff from the thermocouple / oxygen sensor, so if the pilot won't stay on if the button isn't pushed in, you will probably need a new thermocouple.

    Another possible no-cost thing to try is to check if the copper line going from the thermocouple/pilot assembly to the gas control valve is touching the metal frame. I've been doing some looking online and can't find anything on this. I know I've had my heater shut off if either the thermocouple wire OR the thermostat bulb wire touch the frame of the heater. I am making the assumption that neither wire should be grounded to the frame of the heater. I can't find any info to back myself up, though. Heck, I still haven't figured out if that copper wire is truly a wire or if it's a thin tube!

    Although, since you have had the unit shut down several times, it is likely the thermocouple. Here's a page I found with some thermocouples and a link to the directions to replace. Shouldn't be too hard, I think! http://www.waterheaterparts.net/cgi-bin/shopper.exe?keywords=tcouple&search=action (yes, it is for water heaters, but the 'directions' link will be helpful for you too.)

    Good luck.
     
  4. cc-rider

    cc-rider Baroness of TisaWee Farm Supporter

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    JWH123, you're a lifesaver!!! (And not the little round, red kind with a hole in the middle! :) )

    Thank you!
     
  5. Chris, I think your problem is the coppertube that the pilot light flame heats. If you follow that copper line back to the gas valve, it connects with a small hex fitting. that copper tube is called a thermocuple. remove it and take it to a hardware store, get someone there who knows what they are doing and they can sell you a replacement. maybe 5 or 6 bucks. hook the new one back up just like the old one came out. The heat from the pilot light generates a millivolt current that operates a magnetic valve inside the gas valve. that little valve lets gas thru to your pilot light. if the themocuple is bad it wont let the pilot light stay lite.
     
  6. bgak47

    bgak47 Well-Known Member

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    I too would say that it is the thermocouple.