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Discuss How do I clear an airlock in the central heating system after refilling? in the Central Heating Forum area at

  1. Marty32

    Marty32 Guest

    Hi all

    What is the best way to get rid of an airlock on a F&E system as I have drained down the system and then refilled after changing a few rads to new ones?

    I've bled all the rads i.e starting with the ground floor ones and then making my round to all the other rads on the bedroom and landing level?

    Do I have to drain down again?? Any ideas and how to do it are much appreciated!

    Many thanks
  2. PlumbBobBob

    PlumbBobBob Guest

    did you lock open the three/two port when refilling?
  3. glenno1

    glenno1 Guest

    Have you opened all radiator valves,are all radiators affected
    Last edited by a moderator: May 18, 2012
  4. DuncanM

    DuncanM Plumber GSR

    Last time this happened to me I put a garden hose on the drain point and blasted mains water in the the pipework this cleared it. Open vented always a pain for air locks!
  5. mountainman

    mountainman Plumber GSR

    Is there an air bleed valve on a standpipe next to the motorised valve(s) that you have forgotten to bleed?
  6. Bernie2

    Bernie2 Guest

    Fill slowly helps. Turn on pump but not boiler and close rad's all rads except furthest away. Do not let pump run dry. The idea is that the pump will push the water around the furthers part of the system then work back turning on and bleeding rads as you do. Can do it the other way as well. If the airlock is down the cold feed try blowing down the vent. You can sometimes crack the cold feed pipe union at the boiler and let air out. It all depends on where it is.
  7. Marty32

    Marty32 Guest

    Hi all

    I think its a combination of the lot to be fair!

    1. The bathroom rad isn't getting hot and have bled every single radiator including that one!

    2. I believe this system has a two 2x2 port valves so is it ok to move switch across without doing damage? So no I haven't open them in this case or closed them.

    3. I think there is a bleed valve on the vertical standpipe by the HWC but it looks lime scaled up and with a green tinge which I didn't want to open in case I caused a mini flood and couldn't close it again! - Am I ok to open this?

    Is it ok to use the hose pipe main like Duncan said above as I would wanna damage any components in the system especially if 2 port vales were closed etc?

    Many thanks to all for your time

  8. ecowarm

    ecowarm Guest

    Manually open both 2 ports, the lever is normally in the auto position but can be moved to the manual open position. vent from air vent, and the bleed screw on front of pump. job done
  9. Marty32

    Marty32 Guest

    Again - thanks to all for being very informative!

    This forum can be invaluable :yes:
  10. Paulus

    Paulus Plumber

    Yes I've done it many times and it usually clears the airlock.
  11. quality

    quality Plumber GSR

    Slowly slowly catchy money and as eco suggested both valves manual. It can take a while
  12. gary

    gary Guest

    Use your wet vac on the vent pipe! Suck out the blockage.
    • Like Like x 1
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