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How to loosen setscrews on scaleplate to recalibrate pressuretrol

rrwitherspoon
rrwitherspoon Member Posts: 104
Pressuretrol not turning boiler off at 5 psi when set cut in 0.5 psi and cut out 1.5 psi.
Seems not functioning observed pressure up to 5psi I have to turn boiler off myself

Comments

  • BobC
    BobC Member Posts: 5,184
    Have you checked the pigtail is not blocked? While the pressuretrol is off check the little hole at the base of it's brass fitting to make sure that little hole is clear.

    Also make sure the spring has not decoupled from the lever.

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
    rrwitherspoon
  • Jamie Hall
    Jamie Hall Member Posts: 15,746
    That's more than a calibration error. Follow Bob's advice -- and check the pigtail and where it goes into boiler, too.

    Might make sure that it is wired properly, if that doesn't hep...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    The pigtail is clear.The little hole on bottom of pressuretrol is patent. How do you make sure not decoupled from lever?
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Wired as it always was when functioning .Pink wire at top.
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Ok i will try when i get home
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Everything is engaged. No misaligned ferrules
    or levers. Should the contact fork wires of pressuretrol be placed between metal nut and screw? Like a sandwich ? Maybe that is the problem.
  • BobC
    BobC Member Posts: 5,184
    As long as the wire is under the head of the screw or one of it's washers, the contact should be solid. Have you had a chance to turn off the power while the boiler is firing and delivering 5PSI, remove one wire, and see if the boiler starts up when you reapply power? If the boiler. If it does not it indicates something is wrong with the pressuretrol.

    There is always the possibility that the gauge is not working right. At 5PSI I would expect the vents would be hissing a bit loud, any signs of increased noise?

    Bob
    Smith G8-3 with EZ Gas @ 90,000 BTU, Single pipe steam
    Vaporstat with a 12oz cut-out and 4oz cut-in
    3PSI gauge
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Yes, at 5 psi the last radiator supply valve hisses and a leak appears that otherwise you would not even detect
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    I will get vapostat and low pressure gauge installed
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Shall I install vaporstat just like pressuretrol.
    I noticed there 3 wires instead of 2
  • SWEI
    SWEI Member Posts: 7,356
    SPDT terminals. You want break on rise.
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    Does one use all 3 terminals?
  • David Nadle
    David Nadle Member Posts: 624
    No. You want to connect to the two terminals R and B that "break on rise." Don't buy a two terminal vaporstat.
  • rrwitherspoon
    rrwitherspoon Member Posts: 104
    I hope instructions come with vaporstat for wire connections
    L408 1017 model number
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