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Keep getting air in rads

Discussion in 'Plumbing and Central Heating' started by SteveP86, 1 Feb 2017.

  1. SteveP86

    SteveP86

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    Hi folks

    About 2 months ago I replaced my parents heating system up to but not including the boiler. Basically, plumber came in fitted combi to old system then I came in and ripped out all the old rads and pipework. Anyway, piped system up using 22mm flow to a 22x15x15x15 manifold. one 15mm for new extension (3 rads), one 15mm for remainder of downstairs (3 rads) and one for upstairs (3 rads and a dinky small towel rad) The return is done the same way. I've used Hep2o and have used the inserts.

    Problem I have is pressure stays bang on 1 bar but over the course of a couple weeks all the upstairs rads get air in them. One of them gets about 90% air, the other maybe 30% air and the towel rad about 20% air.

    One section of old copper remains on the upstairs section as it wasn't convenient to do at the time. this consists of old 22mm flow and ret, old system pump etc. I will on holidays rip up bedroom floor and get rid of all this so it will be 100% Hep2o. Could air be getting sucked in at a bad connection on the old copper? seems strange as pressure stays the same.

    Any ideas of what to check would be appreciated.

    Steve
     
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  3. oldbuffer

    oldbuffer

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    1. Did you use barrier pipe? If not, air can permeate the pipe walls.
    2. Are you sure its air in the radiators. Could be hydrogen from water attacking steel radiator interiors. Is there inhibitor in the system?
     
  4. dilalio

    dilalio

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    Check for leaks.
    1 bar is too low.
    Gauge may be faulty.
     
  5. HERTS P&D

    HERTS P&D

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    How was the show today?

    Andy
     
  6. dilalio

    dilalio

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    I'm saying nothing! I browsed only and didn't buy a thing [darling]!
    :whistle:;):D

    It was a very enjoyable day and we were in my favourite gastro pub, eating ribeye steaks, cooked in a josper oven, by 4pm! I'm now peckish again and don't know what to cajole the missus into preparing for me, or what else to drink! :confused:
     
  7. dilalio

    dilalio

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    Best freebies of the day...

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  9. HERTS P&D

    HERTS P&D

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    How much did you spend?

    Don't forget it's all tax deductable.

    Andy
     
  10. dilalio

    dilalio

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    In that case... at least £10k :)
     
  11. Gasguru

    Gasguru

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    Why is 1 bar too low? the OP has given no indication that the system height is excessive or the boiler's located in a basement etc.
     
  12. dilalio

    dilalio

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    Normally set it to 1.2-1.4.
    Not a declaration, but from here, I'd expect it to be at that range and see what happens during fully hot?!
     
  13. SteveP86

    SteveP86

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    Boiler is on ground floor. Just a normal up stairs down stairs arrangement. Fernox added at time of filling up. The pipe is double walled Hep2o. Tried to light the "gas" with a lighter when bleeding and also collecting in an upside down cup and no flame or pop. How can air enter system with no visible leaks yet pressure stays the same? All connections checked including under the floor downstairs. I kept joins to a minimum especially downstairs.

    Didn't think 1 bar was especially low? Isn't 1-1.5 the accepted norm?
     
  14. dilalio

    dilalio

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    Bleed air.
    Secure clear bag over discharge/ pressure relief pipe end.
    Fill system to 1.4bar, bleeding further air.
    Check pressure via boiler display if you can.
    Monitor bag contents over 24 hrs.
    Water is getting out; air is getting in!
    It could be leaking at HE and draining via condense trap/pipe.
     
  15. DIYnot Local

    DIYnot Local

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