Posting a message to the forum will remove the above advertisement
  1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. Checkout our Plumbers Insurance area - heavily discounted Public Liability Insurance and Van Insurance specifically designed for plumbers.

Discuss Worcester Bosch Greenstar 24i (installed 2011) pressure dropping & PRV overflow leak in the Central Heating Forum area at

Thread Status:
Not open for further replies.
  1. vivvov

    vivvov New Member

    Hello All
    My Boiler is dropping pressure and the hot taps are running lukewarm. Pressure was never great..3 floors up so only ever just over 1 bar. I called out the Gas Safe engineer who usually services the boiler and he said that the flat plate exchanger would most likely be scaled up (London area) and noticed the PRV overflow was leaking when the central heating was the pressure was dropping.
    He initial took out the exchanger and I had some phosphoric acid to hand so that got rid of the scale...but he couldn’t get to the PRV to replace it (...he’d just come from replacing a PRV on my GFs 16 year old W B 24i RSF..doddle..and then saw that the Greenstar was a whole dfferent much stuff to remove in order to get to the simple task of reaching in and replacing the PRV),
    So he said “not keen to do this..time and effort will be costly just to replace a 20 quid part”..go check and see if my warranty was still in date...6 months out of date. Darn.
    By now he’d put the exchanger back and I’ve got hot water..result. But he seemed unsure about how to access the PRV...he thought he’d have to take out the pump and he wasn’t too sure what the green housing was that is attached to the righthand side of it (bit puzzled by what the green housing actually it the diverter valve motor??).
    Out of interest, I thought it’s a PRV..a simple push fit item...must be an easy way of replacing I googled and youtubed how to replace a PRV on a W B Greenstar 24i but nothing has come it such a difficult job to replace the PRV?
    I’m guessing it’ll be scale build up on the PRV internal valve seat...will repeated flicking the lever remove the scale issue?...or is it possible to somehow unscrew the lever section and then clean the internal rubber seal of the PRV without removing the pump etc in order to do this simple task.
    Also ended up with a spring circlip from somewhere...looks like when the exchanger was replaced the pipe securer circlip wasn’t replaced....oh dear...pointed it out to the engineer but he said not to worry.
    So any info I’d be grateful..
    Thanks in advance.
  2. king of pipes

    king of pipes Trusted Plumber GSR

    Re: Worcester Bosch Greenstar 24i (installed 2011) pressure dropping & PRV overflow l

    Afraid not bud the hydraulic assembly has to come out certainly not a 5 minute fix you need to get your gsr engineer back the EV needs attention to you will have to bite the bullet and get the PRV replaced , there is nothing you can do yourself sorry but that's all you can do .
  3. Dotty

    Dotty Guest

    Re: Worcester Bosch Greenstar 24i (installed 2011) pressure dropping & PRV overflow l

    As above. Get a better gas if your man is puzzled by parts of the boiler that he should know about.
    • Like Like x 1
Similar Threads - Worcester Bosch Greenstar Forum Date
Worcester Bosch Greenstar 28i LOSING PRESSURE Central Heating Forum Apr 11, 2019
Worcester Bosch filter fitted too high? Central Heating Forum May 14, 2019
Thread Status:
Not open for further replies.