worcester 240 combi keep losing pressure please help

[diamond geezer]

my worcester 240 combi keeps losing pressure and going to 0 bar it was on 3 bar other day and poring out into garden i messed about with radiator trying to bring pres down then realised looping valve was open slightly i adjusted it but since then it keeps dropping to 0 bar please help
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[ArtfulBodger]

Your pressure relief valve is letting by (leaking) and needs to be replaced. Simple job but not that cheap. You could try pressurising and operating the PRV manually a few times to see if the valve seat cleans itself but personally I wouldn't hold my breath.

 

[andywolfie]

You need to make sure that your filling loop is off and disconnected,if the pressure still rises the expansion vessel diaphragm has probably failed as the water has nothing to expand against,the prv is set at 3 bar and will lift to releave excess pressure,these never really reseat very well,call out worcester £175 to get them out and includes up to 3 major components.