adding thermostate vavles?

Yes it would - the bypass simply allows the pumped boiler water to circulate - hence not stressing the pump. With the radiators fully open, the water flows through them so the bypass valve can be shut - but always leave one radiator fully open so that the boiler can disperse the heat that it produces.

John
January 2008

thanks john for your quick reply. the boiler is a worcester 350 combi, in the paper work it mentions the presence of a system by-pass, but it only mentions it once, if the boiler definetly had a system by-pass would your answer still be the same?

sands
January 2008

You need to leave one radiator fully open (usually the bathroom one). All of the rest can have thermostatic valves.

John
January 2008