Air in Central heating....?

Discussion in 'Plumbers' Talk' started by giveitago, Jan 31, 2004.

  1. giveitago

    giveitago New Member

    I know this subject has been touched before but still.... i've recently extended my downstairs rads and have got problems with air and i don't know if i've got all the air out of the system or if the system is generating 'new' air.
    fernox inhibitor put in (approx 5 years ago & diluted since..what concentration needed?)
    air purger fitted before pump
    i've bled all rads but still get air gurgling through system , sometimes all rads are hot and pump set on 1 but then after running for 1 hour(s) pump goes noisy and rads cool down.to remedy this i turn heating off and after pump overun i can hear air gugling thru pipes upto header tank..what to do

    Thanks in advance
     
  2. bilco

    bilco New Member

    Hi

    What's this "air purger fitted before pump"?...Sounds like you're drawing air in from somewhere, so is the above on the suction side of pump? If so if it operates whilst pump is running air could be drawn in
     
  3. giveitago

    giveitago New Member

    Hi, i fitted the auto air purger as recommended on the grundfoss leaflet( i think the idea is to stop the pump drawing air in from the vent,don't think it works that well!) The other air purgers i have seen are mounted at the top of a vertical pipe.If i try to explain the pipework forgive me if i use the wrong terms
    If you visualize an 'H' shape the feed from the boiler is the left hand leg rising to the vent over header tank.
    the cross bar of the H is where the air purger is horizontally mounted on a T , the right hand upper section is the feed from the header tank and the pump is placed on what would be the bottom right leg.All of this is upstairs in an airing cupboard with the boiler downstairs
     
  4. capnpugwash

    capnpugwash New Member

    That sounds a bit odd. What is preventing the pump from pushing water back up the feed from the tank? Or through this purge valve and up the overflow? Where is the connection to the HW / Heating?
     
  5. giveitago

    giveitago New Member

    i forgot to say....the pump is vertically mounted and pumps downwards
     
  6. bilco

    bilco New Member

    I can't see how that device is doing anything...

    I presume the return from the heating and cylinder are teed off above the pump...I would reroute the cold feed into the vent as seemingly the most straight foreward solution...that way vent and feed will be ballanced.

    Best way would be to tee into the cold feed above all other connections and run from that tee to a tee in the vent...then add a valve so you end up with one either side of the new tee in the cold feed, leaving the lower one closed (When ever the system is filled opening this valve will enhance the process)

    So you end up with an open cold feed and vent. Both being on the same side of the pump.

    Hope that makes sense
     
  7. serts

    serts New Member

    I might be mistaken but i thought a pump should be installed so that it pumps in an upward direction

    Long Live Dave Voice
     
  8. bilco

    bilco New Member

    Or sideways...or down...well just about any way including up :)
     
  9. giveitago

    giveitago New Member

    I'll have a good look at the pipework Vs what you suggest and hopefully that will be the fix..Many thanks
     

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