my boiler keeps letting water out of the overflow sometimes hot and needs the radiators topping up all time i have an adjustable stopcock does this need to be shut or open what i`m thinking is if it were shut it might stop the overflow?

nigel.stephenson1@ntlworld.com, January 2007

I had a similar problem.
An engineer advised it may be the Mains water on the hot water circuit leaking into the CH system. Mains pressure is much higher than the CH system pressure
Would like confirmation if this could be true?

HarryB, January 2007

Hi
Thats not an overflow, thats a pressure relief valve.
Thats an important safety device and would advise you get a corgi registered gas engineer in to deal with it.
You cant shut that off and working on any appliance if unregistered with corgi can get you a £1000 frine and 6 months in prison, not to mention risking the well being of you and your family.

Subenterprise, January 2007