Slow drop in pressure over summer months

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ChrisCS
ChrisCS Posts: 13
in Radiant Heating

Im hoping for some advice before I turn on my hydronic heating system for the season. Last winter it was about 15-17 psi when running. Now after being off for 5 months, it sits at about 11 or 12 psi. Doea this seem normal? Is it safe to turn on, or should I add a little water to the system?

Thanks for any advice.

Comments

  • bburd
    bburd Posts: 1,338
    edited October 10

    Water expands when heated and contracts when it cools. 11-12 psig is normal for a cold boiler in a building of one or two stories. When the system heats up the pressure should rise back to where you noticed it last season.

    —
    Bburd
    EdTheHeaterMan
  • ChrisCS
    ChrisCS Posts: 13

    Thanks!

  • EdTheHeaterMan
    EdTheHeaterMan Posts: 12,940

    Yea, I would not change anything until you see what happens when you fire it up. Which leads me to a Question.

    Do you shut off the burner switch in the Spring whan you are finished with the heat and then need to turn it back on in the fall when the weather starts to get a little cool outside?

    If you do that is a tell-tail sign that you have a boiler that maintains temperature for an old abandoned tankless hot water coil. If you are not making Domestic Hot Water (DHW) with your heating system, then you don't need to have it maintain a minimum temperature. Maintaining a minimum temperature in the spring and the fall is wasteful and is costing you money in fuel you don't need to burn.

    Ask me about this if you think you have a boiler that maintains a minimum temperature all the time the burner switch is on.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    bburd

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