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Get better at purging air?

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watercourse
watercourse Member Posts: 28
edited October 2023 in Radiant Heating
Update, we're all purged! Just needed to run it in the opposite direction and off of an external water source instead of the plumbed in house water supply.

Any tips to purge air more effectively? 
I have one loop (the one labeled family) that I've purged under house pressure four times and still every time I fire it up I get no flow. The last purge I let it run for over a half hour which seems like overkill. The water came out of the bleed hose fast and the bubbles stopped. Still no flow when the boiler is running, while all the other loops flow great.
I remember this loop gave me some trouble last time I drained and refilled too but don't recall how I finally got this loop moving.




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  • neilc
    neilc Member Posts: 2,707
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    did you burp your purge valve ?

    can you reverse your purge?
    known to beat dead horses
    watercourse
  • neilc
    neilc Member Posts: 2,707
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    valve everything else off?
    then purge? or circulate?
    known to beat dead horses
    watercourse
  • hot_rod
    hot_rod Member Posts: 22,256
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    Is that loop a zone by itself?  Or do other loops flow when that one does?

    If you have multiple other loops on that zone, turn them off and purge just one

    are you sure the thermostat is in fact opening that loop?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    watercourse
  • watercourse
    watercourse Member Posts: 28
    edited October 2023
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    I closed off my boiler and expansion tank, then cranked up the supply water valve pressure to the max it would allow which I think was 50psi. Then I opened each loop individually till the bubbles stopped.
    Then I leveled back the fill pressure and opened the boiler and expansion tank back up.
    Then I turned the system on and set it to send water through various loops to test. Got good flow everywhere except in this one loop.
  • neilc
    neilc Member Posts: 2,707
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    so you're valving off all those other zones at the manifold,
    and isolating flow at the ball valve at the air vent,
    then as the bad zone goes bubble free,
    open and close the ball valve at the airvent to burp that top line,
    known to beat dead horses
    watercourse
  • watercourse
    watercourse Member Posts: 28
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    Update, we're all purged! Just needed to run it in the opposite direction and off of an external water source instead of the plumbed in house water supply.
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    Off topic but it will help. Move the good air separator to the horizontal of the boiler out/supply line and put the pump after it/down stream pumping away from the boiler. Pipe the expansion tank and fill valve to the lower port of the separator. Call in the morning.
    Intplm.
  • Teemok
    Teemok Member, Email Confirmation Posts: 511
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    I hope that what ever zoning arrangement you have allows for the boilers minimum flow rate. One or two of those 1/2 loops is not enough. I see a lot of thermostat wires. 1 gpm per 10,000 btu. input is the standard. I seen it with less but..... it could be kettling to air lock.