16/22 boiler does not work properly after half an hour of switching on, comes on okay heats up the radiators but once the boiler has been working for 45 minutes it takes 4/5 times for the main burners to come on so is constantly igniting. It then cuts in and out continously but still provides heat and hot water

Karim, December 2008

This will be most likely due to a blockage in the feed to the Fan Pressure Switch.

Remocve the tubing and blow air through it to remove any dirt.

Joetheplumber, December 2008