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Purge Pump Puzzler

search for the words "point of no pressure change" and put my last name into the author slot.

ME

Comments

  • Purge Pump Puzzler

    I was on a service call to force purge air from an upstairs FHW zone. The purge points are not very well laid out and the air purger is mounted backwards(not my install). The problem I had was this, with the expansion tank not isolated from the circuit to be purged, the pump acted like it was cavitating and wouldn't move water. I verified my hoses weren't frozen, isolated the expansion tank from the zone and tried again with success. Is there an explanation for this or am I missing something?
  • Big Ed
    Big Ed Member Posts: 1,117
    Double Bubble Tech in Trouble

    I assuming you were trying to use the circulator to force the air out from the lack of a improper purge valve set up ???

    My guess with alot of missing info .......If you have a air bubble on both sides of a circulator (expantion tank-air in radiation)it will tend to pull from the one and push into the other. Gets pretty sloppy, thats why you should install mutiple tanks at the same location.......
  • MGSarkozi
    MGSarkozi Member Posts: 4
    purge pump

    > I was on a service call to force purge air from

    > an upstairs FHW zone. The purge points are not

    > very well laid out and the air purger is mounted

    > backwards(not my install). The problem I had was

    > this, with the expansion tank not isolated from

    > the circuit to be purged, the pump acted like it

    > was cavitating and wouldn't move water. I

    > verified my hoses weren't frozen, isolated the

    > expansion tank from the zone and tried again with

    > success. Is there an explanation for this or am

    > I missing something?



    Were you using an enternal utility pump with short hoses? Are there any flow checks on the lines? What kind of expansion tank, bladder type or galv. tank? Was this zone possiby frozen. I had azone in the second story of a house and they turned the heat down to 50 deg and the outside temps dropped to -10 deg. Also some of the piping went into the eave of the house. I know, I couldn't believe it either.
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