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Mystery One pipe problem

GW Member Posts: 4,675
We took out and reinstalled a piece of BB in a commercial building to make way for a new door installed to an addition. Amazingly, the BB get's air bound every week or so, any ideas? The boiler has pressure, and no other BBs have this problem


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Gary Wilson
Wilson Services, Inc
Northampton, MA
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  • It depends...

    Does the system have a captive air expansion tank (bladder or diaphragm)? If it does, throw an automatic air vent at it and the problem should go away. If it doesn't, look at the possibility of supplying the baseboard off the bottoms of the horizontal mains, where air doesn't like to reside.

    Alterntaively, if the system doesn't have a captive air expansion tank, put one in anyway and install an auto vent at the troublesome BBR and at the outlet of the boiler. Get rid of the air. All of it.

    If the system doesn't have a captive air expansion tank, and you install an AAV, you're setting up a problem with the existing expansion tank and system as a whole.

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