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Help Identifying Low Water Cutoff

HVAC_P
HVAC_P Member Posts: 20
Hello,

I have a customer who has steam boiler that has a leak from the body of the low water cut off, the customer is looking to get one more season out of the boiler. I am having trouble finding a replacement. In the past I have gotten great input from other HVAC contractors on this site. Could anyone point me in the right direction of a LWCO that will work/be compatible? Thank you!







Comments

  • Steamhead
    Steamhead Member Posts: 14,711
    That's an old Watts. AFAIK parts are not available. But the valve and pipe on the bottom is probably standard 3/4" and of course can be replaced.

    To completely replace that unit, you can use either the standard McDonnell & Miller #67, or a Hydrolevel #450 probe-type LWCO in a #711C manifold.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • HVAC_P
    HVAC_P Member Posts: 20
    Steamhead said:

    That's an old Watts. AFAIK parts are not available. But the valve and pipe on the bottom is probably standard 3/4" and of course can be replaced.

    To completely replace that unit, you can use either the standard McDonnell & Miller #67, or a Hydrolevel #450 probe-type LWCO in a #711C manifold.

    Thank you for your response do you know if by chance the standard McDonnell & Miller #67 is line voltage or low voltage for the LWCO wiring? Thank you!
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 9,428
    As far as I know you can use the #67 for line or low voltage. I think they have a different switch available for millivolt if you have a gas valve using that system
  • Steamhead
    Steamhead Member Posts: 14,711

    As far as I know you can use the #67 for line or low voltage. I think they have a different switch available for millivolt if you have a gas valve using that system

    Correct- that's the #67G.
    All Steamed Up, Inc.
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
    Consulting
  • HVAC_P
    HVAC_P Member Posts: 20
    Thanks again as far as replacing the existing LWCO with the McDonnell & Miller #67 is there any repiping that needs to be done or is it pretty much a straight swap?

    Also I couldn't tell if the old Watts is tapped into the back of the boiler, if so, Is it alright to plug that off and pipe the #67 through the water sight gauge using the brass tee they provide?

    Thank you very much
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 9,428
    Yes, the #67 comes with the fittings you need for the most part