Worcester Bosh Combi Boiler - My boiler keeps loosing pressure which i top up regulary (it drops from 1 to nil in about 3 days) also sometimes there is a leak dripping out from the bottom of the boiler (cant get inside to see which component). This problem comes and goes - sometimes it goes weeks without needing any pressure top ups. We have had numerous different maintenance companies round who cannot see anything wrong with any components when they visit.

Sara, June 2007

mmm- hi-spec is quite correct but re pressurising expansion vessels requires an accurate gauge and if it is faulty then it will lose pressure and it will not keep the half bar or whatever pressure you have pumped it to..
If your pressure does go to 3 bar when hot then hi-spec is correct in saying that the vessel may need recharging or replacing.



but -- you say you have a leak - is this at 3 bar or lower?? if you have a leak on the boiler check the pressure relief pipe-work (it goes outside- or should do)-- it may leak intermittently.
But if the boiler is leaking then you have the answer - find leak - cure it.

One more thing - it is known that many systems can entrain air (results in loss of system pressure)-- you could if you know how add Fenox LS1 to the system
get advice from merchants- This will help stop any small leaks on the system - but I would check the boiler carefully first.

dave broadbent, June 2007

THE CLUE MAYBE TAHT YOU CAN GO WEEKS WITHOUT FILLING BOILER THEN OTHER TIMES A FEW DAYS,CAUSE MAY BE EXPANSION VESSEL REQUIRES REPRESURISING THEREFORE ONLY LEAKING WHEN HEATING ON
TEST TO CARRY OUT
FILL BOILER TO 1.5 BAR WHEN SYSTEM COLD IE HEATING OFF THEN TURN HEATING ON WATCH PRESURE GAUGE IF IT RAISES QUICKLY TO OVER 3 BAR BOILER WILL LEAK OUT OF P/R VALVE
THEN WHEN HEATING OFF PRESURE WILL FALL BELOW .5 BAR AND BOILER WILL LEAK FROM AUTO VENT
TO REPAIR EMPTY BOILER AND RE PRIME EXPANSION VESSEL

TONY, June 2007

so what is the question ?

hi-spec plumbing, June 2007