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Discuss Unvented heating system pressure in the Central Heating Forum area at UKPlumbersForums.co.uk.

  1. Matthew Score

    Matthew Score New Member

    I have an issue with a Ideal logic 35kw boiler and system pressure.

    Boiler was over pressuring and the prv kicked into action and released the excess pressure as it should.

    My issue is I have changed the expansion vessel and prv.

    Filled the system to 1.5 and set the heating running and at full temperature it went up to 3.

    The system is quiet large, dormer bungalow with 12 x 600 x 1000 K2 rads.

    Does the system need a second expansion vessel? Is the water volume to large for the one 10l internal vessel?

    I have never had this issue before, just scratching my head a little bit.

    Thank you for any advise given
     
  2. king of pipes

    king of pipes Trusted Plumber GSR

    Left a valve shut ? Maybe
     
  3. Matthew Score

    Matthew Score New Member

    All valves open, pressure slowly builds as the temperature rises and slowly returns as it drops.

    Prv has started to drip again at 2 bar, well ypu cant even really call it a drip but its wet. which I can only put down to muck getting stuck under the seating
     
    • Useful Useful x 1
  4. king of pipes

    king of pipes Trusted Plumber GSR

    Yes that often happens need to change that is a bit on the low side for expansion but you say it worked before , drop the system pressure to 1 bar see what happens ? Kop
     
  5. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Start off with pressure at 1 , not 1.5 .
    Are you gas safe pal ?
     
    • Agree Agree x 1
  6. Matthew Score

    Matthew Score New Member

    Yes Gas safe,

    I don't get my hands dirty to often though as I am manager but this is for my wife's friends, it's always the just can ya jobs

    I haven't seen such a rise in pressure on a system like this before so a little unsure what's going off.
     
  7. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

  8. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    You rang ?
     
  9. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    You check the hose isn't blocked to the expansion vessel

    Rule of thumb 1l per rad
     
  10. townfanjon

    townfanjon Trusted Plumber GSR Top Contributor!!

    Whats the crack for Matthew here
     
  11. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    Mathew send us your gas safe number I will process the request while he's building his post count ;) past 10

    Help away will sort the thread out after
     
  12. Matthew Score

    Matthew Score New Member

    I changed the pipe, it was a bastard to get it to re-seal as it's down the side of the pump and wouldn't engage properly and weeped.
     
  13. ShaunCorbs

    ShaunCorbs S. Mod Trusted Plumber GSR Top Contributor!!

    In the block wasn't crudded up / blocked ?

    Eg got water at expansion vessel
     
  14. SimonG

    SimonG Trusted Plumber Top Contributor!!

    Vessels too small.
     
  15. Matthew Score

    Matthew Score New Member

    It's the standard

    Water freely running out the connection pipe to the vessel.
     
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