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Millivolt

kgalloent
kgalloent Member Posts: 1
in Gas Heating
Need help with millivolt

Comments

  • mattmia2
    mattmia2 Member Posts: 10,212
    in what way?
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,326
    edited December 2021
    Can you describe the issue you are having? EXAMPLES: Pilot won't stay lit, Main burner won't light. Room gets too hot. Room does not get enough heat. Radiators are cold. Cold air from vents. No air from vents. Or any other description that will give us a clue.

    A picture of the thermostat, Gas Valve, or moden number of the appliance would also help. and a picture of the appliance from farther back so we can see the whole thing.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    mattmia2
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 15,989
    @mattmia2 & @EdTheHeaterMan

    I don't know what's wrong with :):) you two today.

    Turn on your x-ray vision

    LOL

    WMno57EdTheHeaterMan
  • HomerJSmith
    HomerJSmith Member Posts: 2,549
    edited December 2021
    kgalloent, I can see you are a man of few words. It might help to understand how a millivolt sys works.

    The heart of the sys is a pilot voltage generator called a Powerpile (Pilot Generator) which is a bimetal device that generates a voltage when heat is applied to it. The pilot flame applies that heat and the Powerpile generates about 750 millivolts. This is very low voltage, less than 1 volt. This 750 millivolts opens the gas valve, but before it can do that the current goes thru the safety circuit and sometimes a thermostat. The resulting voltage can drop to around 400 millivolts.

    Powerpiles do go bad and needs to be replaced. Any switches in the safety circuit can go bad, too, interrupting the current flow to the gas valve. Lack of a pilot flame stops the whole process.

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