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Rick Ridley
Rick Ridley, UK Heating Engineer
Category: UK Plumbing
Satisfied Customers: 2708
Experience:  30 Years on the tools, now retired, Ex CORGI
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My Glow-worm 30 cxi boiler central heating pressure is dropping

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My Glow-worm 30 cxi boiler central heating pressure is dropping continuously. Have to re-pressurize every day and water collected from the outside overflow pipe is over 2 litres as day. Has the 'safety discharge valve' failed please?

If this is the problem can I fit a new one myself?
Hi I am Rick, UK Plumber, and I specialize on Boiler problems,the pressure relief valve could well be leaking, but it could also be the pressure vessel, to find which you need to monitor the system pressure, cold it should be around 1.5 bar as the system (heating) heats up it will go to about 1.8 maybe 2 bar, if this is the case then yes the pressure relief valve needs replacing, a simple DIY job, if however it goes to 3 bar then the pressure vessel has failed, not so easy to fix, Rick
Customer: replied 4 years ago.

Hi Rick


Good answer. It is the pressure vessel. I guess the best option is a new boiler. Any recomendations please.


BTW I tried to click accept answer but the web page didn't respond. Please be advised that I do accept your answer and hope you are paid


All the best


It does not have to be a new boiler, you can simply gut in a regular pressure vessel some place near the boiler if you can find space for a large football sized bit of kit, I cannot really advise on a particular boiler on here as I cannot favor one manufacturer over another, re the accept issue, yes sometime things lock up, but it should work OK next time you log in, Rick
Rick Ridley and 2 other UK Plumbing Specialists are ready to help you
Very well done, this is the first time ever that I have heard of a pressure vessel being repaired, Rick

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