The boiler only starts the fan and fires up if i blow into the Air Pressure Switch. The Mid Position Valve and Pump are working. The boiler will run for about 18 minutes making hot water and heating the radiators but wont restart until i blow into the APS again.

Any suggestions?
I would like to get the system working before i sign up for a care plan.

PensionPete, November 2008

Make sure the air pressure tubes are both clear and not damaged or kinked, if they are ok then you probably need a new APS

Martin, November 2008