I have got an old glowworm capricorn 240/6 back boiler,pilot light is lit but main boiler will not lite up could this be the thermostat, as when i adjust the knob on stat it should start up but it don't ,i have took phial out and placed it into both cold and luke warm water but nothing happens this has what has led me to say can the stat be packed up

Lee james, October 2006

make sure the gas valve knob is turned to the flame symbol and not the spark symbol, if it is and you are sure the pilot is alight then turn the stat, it it clicks then you will need to test if there is 240v at the gas valve,
this really is a job for a proffessional due to the safety implication related to old open flued appliances.

MIKE, October 2006