My baxi 105 has the fan or flue fault LED flashing.

I have removed the covers and the fan does not operate when there is a demand.

I am guessing that the fan needs to be replaced, if this is the case, how do i do it?

This model is the one with the fan on the top left near the final flue exit.

i am not an engineer, so i hope i have diagnosed and described the problem correctly.

ged, October 2007

I bought a new PCB for £72 plus VAT, swapped it for the old one... now it works.

ged, November 2007

thx for that,
colleague is CG reg eng, I am a sparky..
as most faults like these are a process of ellimination and can be costly - with most boilers they are more and more reliant on technology.
I get quite a few calls to diagnose PCB faults from engs or returns for fix post fault replacement.
Anyhow my CG reg eng - cast an eye and checked prior to usage.. he was happy to do so due the nature of the fault.

Agree though always seek qualified assistance -
will enhance more if/when posting any aid in the future - Paul

Paul, October 2007

Ged,
just had the same fault - doubt its the fan as there are problems it seems with the relays on the PCB.
See details below as added this info to another string within this site earlier
****
Just had a fan/flue light flashing on my 105e

primarily checked the flue for blockage (you never know) gave the unit a good clean/vac out
Checked power to Fan when hot water demanded - no output
Still no joy

Ordered replacement PCB - Part No: 5112380 (was 248074)
found this to be an upgraded version - better it seems
off ebay BNIB Item number: 150173291687 for reference price
£48.50 inc P&P

Fitted - (ensure you switch to reset for 3 secs before returning dial to On position) and that power to the unit is isolated - off at fusebox if not on dedicated trip/circuit.
If unsure seek professional help!

Problem Solved
Have my board at work to tinker with and repair for a spare
suspect the Fan relay - but struggling to find schematic details
so will probably replace both suspects!
hope this helps Paul
hfm@ntlworld.com

Paul Hawksworth, October 2007

as you are not a corgi gas engineer you have broken the law.
get an qualified engineer in to repair gas appliances and dont risk yours and others lives.

mrgas, October 2007