Each week I need to top the pressure up, as it drops from 1.5 to 0.5 over a week, HW & CH working fine. Boiler has not been serviced for at least 5 years. There is discharge from the pressure release valve outside - crud and steam. From reading other discussions this points, I believe, to a problem with the pressure release valve or the expansion vessel. On this model the expansion vessel is a sealed unit and replacement requires removing the gas valve, which I'm not qualified to attempt. Should I replace the prv and see if this fixes the problem and is there a test I can run first.
Worcester Bosch 240 combi rsf pressure dropping
- Thread starter grabling
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There is a test you can do. Completely depressurise the system and check the exp vessel precharge via the schraeder valve. If low then pump up to .75bar. Change the PRV at the same time. Refill system and bleed air and see how it goes.
Thank-you for the quick response. Can I just check that by depressurise you mean drain down. Also the exp vessel is a sealed unit and I haven't noticed a valve on it - that said I haven't removed all of the boiler casing so it may be that it's just hidden from view.
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