Hi. My boiler does not always start running when the programmer and thermostat are both "ON". The programmer light is on and the thermostat is calling for heat, but the boiler just sits there, and the pump does not run. Sometimes I can solve it by switching the programmer on and off a few times. Is the issue likely to be a duff programmer, or a fault on the boiler PCB - I'm not sure where the "brain" of the system is?

Mark T, January 2015

I would check the motorised valve,if you have 2x2 port valves get somebody to turn programmer on while feeling the valve for the heating after 10-15 secs you should here it click,its the switch in the valve that starts the pump and fires the boiler up.If there is a 3 port valve then the programmer is suspect but i would short out the relevant connections on the connection plate at the back of the clock to prove a point ( but i am an electrician so im confidant with what im doing ) or test in the junction box to see where the fault is

toptrish, January 2015