combi again

[andy100]

I have a baxi bahama 100 combi, after the heating has been on for a while and the stat has switched off.
When you turn on a hot tap the boiler fan starts up the flow censers appear to work correctly, but there is no ignition sequence ie no spark.
This has happened before, I traced the fault to the tubes on the pressure switch which had split. But every thing seems to be ok there.
Also so it could be my imagination but if you operate the boiler with the panel of giving you access to the fan etc, it appears to work ok,would this point towards the air pressure switch??

Any help please

Andy

 

[andy100]

Should anyone else have this problem try this.
I connected an AVO meter on the black terminal on the pressure switch the voltage rose and then fell repeatedly this indicated a lack of suction from the fan, on removing the fan I could see a build up of green gunge around the outlet to the tubes, after removing this the boiler works fine.