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Pigtail question regarding Gauge on residential one pipe steam

RTW
RTW Member Posts: 216

The port off front of boiler has a stem that rises up to a Tee fitting. Off to one side it has a pigtail for the pressuretrol and off the other side of the Tee it goes directly into the 1 to 30psi gauge ( that must be 30 years old). The dial has ever moved to my knowledge and the pressuretrol is on the lowest setting - QUESTION: should the gauge have a pigtail since my service tech has never mentioned it even when he last checked the pigtail, which was fine? I know the tech added some water to the pigtail when he re-installed it

Regards

RTW

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Comments

  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,515

    Most gauges say on the face that it has an Internal syphon. But mots think for longer gauge life it should be on a pigtail. Use all brass fititings on the pressure trol and gauge and you will have fewer problems.

  • RTW
    RTW Member Posts: 216

    YES, the front of gauge has " internal syphon gauge" printed on it

  • pecmsg
    pecmsg Member Posts: 5,883

    That 0-30psig gauge is required by code. Gauges are only accurate when reading in the middle range. With your system operating at less than 2#'s you shouldn't notice any movement.

    You can install a 0-5# gauge and isolation valve but the 0-30# must remain.

    Mad Dog_2
  • RTW
    RTW Member Posts: 216

    Lastly, is there a way my service tech can test the 0 - 30psi gauge when he returns to service/clean boiler after the heating season or is this an overkill request? Regards, RTW

  • Jamie Hall
    Jamie Hall Member Posts: 25,859

    That's overkill. Odds are that the gauge will read something, anyway, if the boiler pressure gets up in the 5 to 10 pound range, at which point you have other things to worry about. Leave it.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2Intplm.
  • ChrisJ
    ChrisJ Member Posts: 16,577
    edited April 2024

    Most cheaper gauges that I've seen fall under the +- 3-2-3 category. My guess is the cheap gauges supplied with boilers do as well.

    That means the middle 50% is 2% accuracy and below that and above are 3%. It doesn't mean it's not accurate at the extremes, it's simply a little less accurate.

    So in the middle 50% of the gauge a 30 PSI gauge is within +-0.6 PSI and at the extremes it's within +-0.9 PSI.

    If I did my math correctly.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • Mad Dog_2
    Mad Dog_2 Member Posts: 7,930

    Ya gotta spend a few bucks to get a qaulity Guage today. Mad Dog

  • ChrisJ
    ChrisJ Member Posts: 16,577

    The liquid filled Yellowjacket gauges I bought are class 1 gauges, so 1% across the entire range.

    I think they were close to $80 each for the lowside and highside gauges not including a manifold or anything.

    But that's not necessary for a steam boiler. Any cheap 3-2-3 gauge is fine, it would just be nice to have an added low pressure gauge in addition to the required 30 psi gauge.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • pecmsg
    pecmsg Member Posts: 5,883

    why?

    The system will never run with enough pressure for you to get an accurate reading?

  • SteamingatMohawk
    SteamingatMohawk Member Posts: 1,047

    @ChrisJ What? You didn't mention the Magnahelics?

  • ChrisJ
    ChrisJ Member Posts: 16,577

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

  • Sylvain
    Sylvain Member Posts: 154

    Isn't it 2% of full scale. That means on a 0 - 5 psi scale 2% of 5 psi.

    That is a common way to express accuracy for analog scales.

    ChrisJ
  • ChrisJ
    ChrisJ Member Posts: 16,577

    Yes,

    But what I meant was it's 2% off across the entire range, as opposed to the 3-2-3 gauges.

    Single pipe 392sqft system with an EG-40 rated for 325sqft and it's silent and balanced at all times.

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