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It looks like I am having a problem with a gas valve on a munchkin boiler. Is there anyone who might be able to tell me what the gas pressure from the gas valve to the burner on a LP boiler should be. Thanks, Mike


  • Mark Hunt
    Mark Hunt Member Posts: 4,909

    model do you have?

    Have you tested with a combustion analyser, specifically the CO levels during firing?

    Mark H

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  • Gas

    The boiler I am talking about is a 80MLP and it wont fire. Yes there is gas pressure of 12"wc supplyed to the valve and the valve gets 24 volt. I hear the solinoid click but it does not appear to open. Any Ideas short of changing the gas valve?
  • Joh n Brickey
    Joh n Brickey Member Posts: 43
    Munchkin gas valve

    Make sure that there are no obsrtuctiuons in the gas valve or the orfices. Like spider webs or pipe dope. If there are none change the gas valve
  • Mark Hunt
    Mark Hunt Member Posts: 4,909
    Are you getting

    an error code?

    Is this boiler equipped with the 925 control?

    Mark H

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  • Munchkin

    I am assuming this is an older model:With WHC1100 board

    To check if the gas valve is getting power, when you see spark in the chamber touch the blue coil with a metal screwdriver to feel if the coil is magnetized. If you feel the coil is magnetized then the unit is getting power. You should have 24 volts DC (not AC) at the first 2 pins at the gas valve. The power wire changes AC power to DC at the valve.

    If the unit is sparking and the gas valve is open but still no ignition try the following. Take your hand and cover one half to two - thirds of the venturi air intake while the unit is sparking. Do not put your fingers into the venturi air intake! If the unit now lights, adjust the gas adjustment screw counter-clockwise until smooth ignition or to CO levels. For the 80M on LP that should be between 10 - 100 ppm. The higher is for high fire the lower is on low fire.

    Is the LED flashing any code?

    The throttle adjustment screw is the screw closest to the air inlet. If you have the gas valve inlet to your right, then the adjustment is direcly to the left of the air inlet. DO NOT ADJUST THE TORX HEAD SCREW.

    Your CO2 for LP is 9.5% to 10.5%
  • 925

    The control is a 925 and thanks for your ideas around this for it is a new system and i so much dont want to tell the home owner there is a problem.I will be trying all mentioned ideas on Mon and let you all know what I have found out. Oh ya, there is a F09 lockout and this is ignition problems.
  • Tim Thanks

    It worked. I covered the vortx air intake 2/3rds and the Munchkin fired. I then went counter clockwise with the screw and the Munchkin fires nice. Thanks, mike
  • Glad to help

    Mike. Do you need some literature on the Munchkin? If you do send me an e-mail with your address and I will send it off to you.
  • munchkin-man
    munchkin-man Member Posts: 247
    thanks to all for your help

    I was not in a position to go on line to see this issue yesterday. Thanks for your help guys
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