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Proactive Maintenance for Controls on a 37 Year Old Utica MGB100 Boiler

allthumbs Member Posts: 10
I have had no problems with the E6H86 gas valve on my 37 year old boiler. I have replaced the White Rodgers 5059-23 Pilot Relite Control and leaded electrode. I want to have on hand a spare mercury switch module that plugs into the gas valve. I just don't know what part number is applicable. The original mercury switch is #5098 without subtype. The switches available are 5098-20, 5098-134, 5098-156. Does anyone know which switch is compatible with my gas valve?


  • Steamhead
    Steamhead Member Posts: 16,272
    That gas valve is no longer available.

    Can you post a pic of the pilot assembly, so we can see what type it is?
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • retiredguy
    retiredguy Member Posts: 801
    Try "supplyhouse.com", They may have what you are looking for.
    JUGHNE Member Posts: 10,801
    I had one fail on a furnace. At the time the recommended replacement was a standing pilot valve. Still working fine.

    The advantage is keeping your boiler warm in the humid basement during the summer.
    But, some gas usage needed.
  • allthumbs
    allthumbs Member Posts: 10
    Here's a picture of the pilot assembly on the boiler flange. I don't dare unbolt it because I'm afraid it will cause the mercury bulb to disintegrate from old age.
  • allthumbs
    allthumbs Member Posts: 10
    I have bitten the bullet and purchased a style #19 mercury switch. I seem to remember the bulb was perfectly straight on the old one. The #19 is a straight bulb, and the #20 has a bulge in it. I'll only know for sure when the switch is replaced.