I have a vcw-gb 242 combi boiler and now find the central heating wont fire up. When i turn on the hot water tap the boiler fires up okay but when i start the central heating heating system the pump starts but there is no boiler flame..thus no central heating. Coldest days of the year so far and no central heating.Help

Les Downs, November 2010

It'll be the servo valve not returning to the heating position.
Probable cause is a water leak (minor) through the top of the water section, which gums up the push rod to the servo valve, the rod gets stuck in its sleeve therefore not allowing servo valve to return.

Replace the stuffing box on the top of the water section, and clean & grease the push rod above.

Carefree, November 2010