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  1. #1
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    393

    Thermocouple in propane units

    Has anyone else seen a higher failure rate with thermocouples and thermopiles with LP vs. natural gas? LP seens to burn the tips off of the TC...or is it just my bad luck? I find this mostly on DV units.

  2. #2
    Join Date
    Dec 2005
    Posts
    783
    Make sure the pilot has a propane orifice in it and not one for natural gas. To large of a pilot flame will cause burnout. I have seen this on converted units. They change out the burner orifice but forgot the pilot.

  3. #3
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    393
    They have the correct orfice, but I have had to turn the pilot down some after I replaced the parts. The TC and TP glow a bright red.

    A hearth shop owner mentioned that in the last few years that the LP companies started adding something to the gas that caused it to burn differently.

  4. #4
    Join Date
    Mar 2007
    Location
    manitoba canada
    Posts
    153
    I have not noticed or heard of our units burning out thermopiles even when converted and we produce about 40,000 units per year.

  5. #5
    Join Date
    Aug 2004
    Location
    S.E. Pa
    Posts
    6,291

    Cool LP TC replacements

    LP burns hotter than NG. I almost always turn the pilot flame down on LP units more than NG. I adjust all pilot flames because most mfrs. ship the unit with the screw wide open. On thermopile units, I set the pilot flame so the TP generates 450-550mv.

    Do Not change brands or types of TCs as this would change the dropout rate of the pilot. This would void the warranty and listing of the appliance. When in doubt, contact the mfr's Technical Service with model and serial#. They might appreciate the feedback. If no one contacts the mfr., how would they know there is a problem out there? Be a part of the solution (and yes, quality control).

  6. #6
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    393
    The last one that I replaced, the retailer took pics of the old TC and sent pics to the mfg. The DV was installed last June and the customer has been having problems for the last three months with it.

    Oh yes, that glowing TP was reading 830mv when I got there !!!!! Needless to say that I had to tone that pilot down JUST a wee bit.

  7. #7
    Join Date
    May 2005
    Location
    Madison, WI
    Posts
    1,078
    I have always found that LP destroys TC's much faster than NG. Seems, like you said, LP burnjs the tips off them, or makes the heads "explode". Usually caused because no one bothers to adjust the pilot flame from the wide open default settings.

  8. #8
    Join Date
    Jul 2006
    Location
    NJ
    Posts
    356
    Quote Originally Posted by logdoc_rob View Post
    The last one that I replaced, the retailer took pics of the old TC and sent pics to the mfg. The DV was installed last June and the customer has been having problems for the last three months with it.

    Oh yes, that glowing TP was reading 830mv when I got there !!!!! Needless to say that I had to tone that pilot down JUST a wee bit.
    I wish I could get 830 on a pool heater, I wouldn't change a thing

  9. #9
    Join Date
    Jul 2006
    Location
    Virginia
    Posts
    393
    Too funny bonafide !!!! I was skeered that a lightning bolt was going to shoot out of the control valve and electrocute me!!!

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