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Discuss fixing airlocks in system, tips? in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Mranon1989

    Mranon1989 Member

    Hey everyone, I've dealt with a few bad airlocks over the years but was wondering if anyone had any good tricks to get them out faster/easier.

    I've always been told to just leave it on constant until it settles and another time we had this plumber help us and he removed the thermostats on the boiler and let it boil. It worked in fairness.

    I got a system which I've recently worked on, replaced all the valves and all downstairs aren't working. The pipe work is in 10mm going into the floor and up to each rad.

    I got the customer breathing down my neck because its a holiday let and they've got people staying for a week starting tonight. I'm hope it will resolve itself over night but incase not I'll have to go there in the morning and try to sort it!

    Any ideas?
  2. Riley

    Riley S. Mod Trusted Plumber GSR Top Contributor!!

    Mains fill.
  3. CBW1982

    CBW1982 Plumber GSR Top Contributor!!

    Do you get water from bleed vent? Is it zoned off? Have you opened the lock shields and balanced correctly? Have you removed the trv heads to see if that works?
  4. Jerry

    Jerry GSR

    If it's open vent, jam a hose pipe into the expansion pipe of the f&e tank and blow the sucker out.

    Get the pump working at max

    And watch out for the tank overflowing.
    • Like Like x 1
  5. Jimmy18

    Jimmy18 GSR

    Wet vac on the air vent on the rad valve works for me or mains fill
    • Like Like x 1
    • Agree Agree x 1
  6. Mranon1989

    Mranon1989 Member

    Thanks for the replies lads.

    I done the mains pressure thing on a open vent before, for the hot though. Apprentice was screwed on a hobble so I cleared it for him.

    Yeah got air from vent. All rads bled, most of upstairs are working bar one or two, turned the hot ones off and waited. I fitted the rads with those locksheild drain off ones so I’m thinking of pressuring the system, linking the hose to a rad and flushing it through!
    • Like Like x 1
  7. Rob Foster

    Rob Foster Top Contributor!!

    Hi Mranon, doing the mains pressure flush is the best way. Its simpler with a closed system as there is no f and e tank to overflow. Mains pressure in at one drain off, out at another. If there is sludge in the system isolate the boiler. open and close rads in a co ordinated manner and monitor the outflow to see any sludge. When satisfied fill rads slowly bottom to top ones in property.
    Then check for leaks add inhibitor open boiler and vent, switch blipping the pump.
    I would tell customer that the full hit is best in the long run, dont advise penny pinching measures. centralheatking
  8. Coby kenny AGUILAR

    Coby kenny AGUILAR Member

    No heating downstairs is normally a pump problem
    • Like Like x 2
  9. Stigster

    Stigster Plumber

    I would try to heat just one rad at a time. Close all but one and see if it gets hot. If it does, close that and move on to the next. If you can get every radiator hot individually at best it will shift any air trapped in the pipework and at least show that every rad can get hot and is not blocked. If this works and every rad gets heat individually I'd look at balancing the system and see if that gets everything warming evenly.
  10. Mranon1989

    Mranon1989 Member

    Thanks for your input people!

    I managed to clear it without having to use mains pressure.

    I linked a hose to a couple of the rads downstairs, opened the drain offs for a few seconds on each and boom, it all worked thankfully!

    Air got into the coil on the cylinder though and that was a bugger to get out but managed it eventually.

    I hate open vent lol
  11. Stigster

    Stigster Plumber

    Well done in getting it sorted and thanks for getting back to us. As for hating open vent systems I understand why but these airlocks are really a design issue. With everything done just right and installed correctly they can be very reliable as far as not air locking goes. I appreciate it's not always possible to get everything with a slight rise to high points but when done perfectly, they will fill just fine without issues. The problem is many of them aren't installed like that.
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