How to change a photocell on a Firebird Enviromax boiler?

Firebird c26 90k, fan starts up but burner doesn't light, last serviced 4 years ago. Suspect photocell.
Prof, November 2015


done
Not being an expert on gas boilers I might be wrong but usually the photocell only comes into play after the burner has lit,it could be the air pressure switch or the valve itself

toptrish, November 2015
link Click here to see other fixes for Firebird.