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Intermittent Pilot Ignition

JEMM55 Member Posts: 47
I still have this problem and it seems nobody can figure it out..

Ultimately I will be changing to a new powerflame burner due to this MYSTERY!!!

Loss of pressure across pilot solenoid

I have a Weil McClain model 580 with a Midco burner.

I am having a problem with the pilot.... it lights only intermittently when the boiler calls for heat or hot water.

Everything is freshly tuned...ignition, flame rod, all electronics ignition check out and there is excellent spark

The main gas pressure is over 6in col water. The pressure before the solenoid is also 6 after a 30 inch run past the regulator. The burner calls for 3.5 in column after the solenoid. BUT....No matter what I do the pressure drops to 1.8 max.

New solenoid, proper electric feed, everything clean but can't get higher pressure so the pilot is lighting only intermittently.

This is the mystery nobody can figure out...Any ideas are welcome........help?


  • Zman
    Zman Member Posts: 7,441
    Have you?

    Have you verified that you have the correct pilot orifice? 
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Sam81
    Sam81 Member Posts: 37
    Pilot pressure drop

    Have u check ur gas supply u maybee having to small meter or bad regulator, what could cause low volume
  • JEMM55
    JEMM55 Member Posts: 47
    The regulator and meter all check out with proper pressure

    Pilot orifice is clean and properly sized
    EBEBRATT-Ed Member Posts: 13,346
    pilot problem

    By all means make sure you have the correct pilot orifice as posted above. It sounds to me like the gas supply to the solenoid is restricted. Maybe a long run of tubing or  undersized tubing. If this is 1/4 or 3/8 tubing with 1/8 or 1/4 " fittings you can't run to much of this without getting a pressure drop. Cut a tee in right at the solenoid valve inlet and see if the pressure drops when the pilot tries to light

  • JEMM55
    JEMM55 Member Posts: 47

    We have a tee there and the water column stays consistent before the solenoid...after the solenoid the pressure drops.

    changed the solenoid and still is a problem.
  • JEMM55
    JEMM55 Member Posts: 47

  • JEMM55
    JEMM55 Member Posts: 47
    There is no way to change the pilot orifice.

    It is part of the gun
This discussion has been closed.