Can't re-pressurise Worcester Bosch

Discussion in 'Plumbers' Talk' started by Cadishead67, Dec 11, 2021.

  1. Cadishead67

    Cadishead67 Member

    Hi,

    I have bought a house which has a Worcest Bosch Greenstar boiler in. The pressure always sits just under 1 bar. I have recently drained the system and repressurised it and same again.

    On the filling loop, there is a non-return valve on the hot side - see photo. I suspect there is an issue with this because water flows (I can hear it) until around 1 bar and then stops. The flow is good, I have disconnected it and checked.

    Any ideas?

    Cad
     

    Attached Files:

  2. dcox

    dcox Screwfix Select

    Low mains pressure? If the mains is only around 1 bar then you won’t be able to repressurise your heating system above that.
     
    just pumps and terrymac like this.
  3. Cadishead67

    Cadishead67 Member


    Could be, it is at the top of a hill. Although the water flow from the tap looks good. Is there any way of overcoming this or will 1 bar be sufficient?
     
  4. Jimbo

    Jimbo Screwfix Select

    1 bar cold is probably enough. The expansion vessel dry pressure should really be lowered in that case so that it has some reserve capacity to hold the pressure steady against minor seepage, but if it’s all charged up and working then probably just leave it. Be sure to add inhibitor if it’s been drained btw.
     
  5. terrymac

    terrymac Screwfix Select

    Should work just fine with 1 bar
     
  6. MiracleGeneral

    MiracleGeneral New Member

    Had this on mine.
    Tap the pressure gauge a few times like you would a barometer.
     
  7. Cadishead67

    Cadishead67 Member

    I actually thought that it was water pressure. Yesterday I got about 1.25 bar into the system. I had to drain it later yesterday slightly to put some inhibitor into it. I then repressureised it.

    Just come this morning and it has lost a bit of pressure and there is water under the boiler which I think has come from the white plastic pipe that is going outside. Anybody got any ideas?
     
  8. Jimbo

    Jimbo Screwfix Select

    The white plastic pipe is the condensate drain. There is likely a trap in the boiler, which might unscrew from below, which could need cleaning.
     

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