I have a worcerster bolier which is nearly 2 years old, the pressure bar keeps dropping down into the red section.I increase the presure back up to one n half which is what it normally runs at, but it drops back down within hours.I have checked for leaks, i have none, I have bled all the radiators.Istill have heating and hot water .Ijust need to know why the pressure keeps dropping and is it dangerous.
I've had this problem many times.
It sounds like a faulty pressure releif valve inside the boiler.
have a look outside there should be a copper pipe, if there is water marks, algae. the valave has gone.
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