how can i fix my baxi 105e combi boiler?

The 50 degree light flashing shows that there is a fault on the fan or flue. i have always found that if it isnt the flue that has parted(vertical flue usually) than the air pressure switch will need replacing. I come across this fault alot at work and i garantee that this part will solve your problem.
I wouldnt recomend changing the p.c.b before replacing the a.p.s

lee, eastyork
September 2008

Sounds like relay on pcb isnt working prop, replace pcb baxi have made a new upgrade pcb for the 105 boiler

Baximan
September 2008

This is most likely to be fan or fan pressure switch. The flashing light at 50 degrees points us to these. Could be other things but these are most likely. If you can hear the fan running but boiler doesn't light then I'd almost certainly say it's the FPS. Have changed these in the past on these boilers but never a fan yet.

Rob, Derby
August 2008