when i switch the boiler on; the fan comes on but does not light up. e34 shows up.

paul, July 2007

The air pressure switch is not closing

could be
low pressure differential between flue inlet and outlet caused by

leak in the tubing or tube/fan connection
leaking fan seal or not seated properly
Dirty fan
blockage in the flue inlet or outlet

OR defective pressure switch (diaphragm or switch)

andy, July 2009

e34 represents an air pressure switch problem...I suggest checking the aps tube from aps to fan for a blockage....probably blocked with water

IAN DITCHBURN, July 2007