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Allen screw size on MCDONNELL & MILLER 67 blow down valve

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Old_Steam
Old_Steam Member Posts: 18
edited March 8 in THE MAIN WALL

Can anyone advise the size Allen key needed for the Allen head cap screws on the MCDONNELL & MILLER 67 blow down valve body? I have to remove some p[arts to get to it, and i want to make sure i have the right socket before i get into it.

Thanks

screws.png

Comments

  • 109A_5
    109A_5 Member Posts: 3,915

    I believe it is 1/4 Inch. Stand by I'll check.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,915

    Yes, 1/4 Inch Hex. I checked the screws on my boiler and my spare stock.

    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • 109A_5
    109A_5 Member Posts: 3,915

    I believe they have been shipping the units for decades with the 1/4 Inch hex drive cap screws. Yet the manual as of 2019 still refers to the old flat head screws.

    image.png image.png image.png
    National - U.S. Gas Boiler 45+ Years Old
    Steam 300 SQ. FT. - EDR 347
    One Pipe System
  • Steamhead
    Steamhead Member Posts: 18,421

    I've seen both flathead and Allen screws in the field.

    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting

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