How do I find fault on a Worcester Heatslave 15/19 conventional flue?

im an oftec engineer.
sounds like the circulation water pump is faulty.
remove the silver 'button' on face of pump with boiler running. the centre spindle of the impeller should be spinning.
if not, get an engineer to change the pump.
and your pressure should be at 1 bar cold.

mark properjob
February 2012

have u checked the water pressure in system. it shud be 1.5bar

michael
January 2012