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Heatmaker Mark 2

Had one a few weeks ago that turned out to be ghost flow on the domestic line.


  • RonNE
    RonNE Member Posts: 7
    Heatmaker Mark II

    Anyone real familar with these Mark 2 out there. Having a problem with the house heat circ. The low limit won't come out of the domestic cycle it seems. The internal circ keeps running and running, the boiler will cycle properly for domestic from about 140 to 180. Jumped out and bypass low limit house circ runs fine. Take off low limit and heat up with heat gun also will cause it to switch over and power up R1 and house circ. This is the 3rd low limit and I cannot believe for a second it is defective( already been down that road). The limit is right down on tank, covered with insulation, it just doesn't seem to feel the temperature, pipe is damn hot, no problem with domestic.
    Anyone got any thoughts, real stuck this time.
  • [Deleted User]
    Texas Instruments...

    use to make the bimetal power transfer switch, and they are about as accurate and reliable as...

    Can't think of anything that unreliable.

    Get a remote bulb SPDT aquastat to replace it with and it will work fine. Better start looking for a replacement boiler too. No parts available to my knowledge.

  • Tony_23
    Tony_23 Member Posts: 1,033

    Parts, that is. Tough though.

    Aluminum grease helps. Maybe the coil needs a flush ?

    Just decommissioned another one of my long standing service customers and scarfed all the parts I was comfortable reusing.

    I've still got about six still going.
  • Unknown
    Try this.....


  • Get in touch with

    Laars as they distribute the Endurance. The Heatmaker was the unit before Endurance from Trianco, Laars bought out the line and some of the old Trianco Heatmaker folks are still at Laars and I am sure there are still parts.
This discussion has been closed.