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Bad expansion tank?

tomd7735 Member Posts: 11
Iffy call. Depends where you are and what the night-time temps are. In a case of below freezing temps expected, and if the RV's were draining into a safe place (no water damage) like floor drains, I would reduce the auto feed makeup pressure, lower the high limit, and get to the supply house when they opened.
Some of the supply houses around here will open for emergencies with an on-call guy. Of course, it depends how good your account is with them...
Oh, and if it's it a comm'l boiler, shut off the chemical treatment for the night. No sense wasting it down the drain.


    HAROLDS Member Posts: 9
    Bad expansion tank

    Went on a call today, the relief valves were leaking. When I got to the site I reset the system pressure to 35 lbs and started the first boiler, water temp went from 160 to 170 in a short time but the pressure shot 50lbs off went the relief valves, I had the make up water valved off. So I checked the exp. tank , I tried to check the air pressure charge but water shot out of the stem no air at all. What can I do to get by until I can get new tank or a new bladder?
  • jim lockard_3
    jim lockard_3 Member Posts: 5

    Nothing--water expands when heated.
  • Empire_2
    Empire_2 Member Posts: 2,343

    Why do you have you system pressure @ 35 psi? Commercial building? What model tank do you have? Sounds like Jim is right...:-)

    Mike T.
  • heatboy
    heatboy Member Posts: 1,468
    If you have water.....

    .....at the valve stem, the tank bladder has gone bad and the tank needs replacement.

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