i have a 30c glow worm boiler and all of a sudden the radiators have stopped heating up. the boiler appears to be working, the fan is going and the pump is going but there i have no warm rads. PLEASE COULD ANYONE SHED SOME LIGHT AS TO WHAT THE PROBLEM COULD BE? THANKS.

SARAHDIY, January 2010

There's a valve - it directs the heated water to the rads or the taps (hot water tank) sometimes it gets stuck in the wrong position.

The "diverter valve" is an electrically operated valve which switches the hot water flowing from the boiler to the radiators or hot water cylinder depending on which thermostat is calling for heat. If both are calling for heat at the same time the valve will assume a 'mid-position', sharing the flow between cylinder and radiators. The diverter valve is sometimes called a 'mid-position valve' for this reason.

http://www.centralheating-diy.co.uk/images/3_port.jpg

Peccavi, January 2010