Promax HE15 fault

[Colin108]

Boiler calls for heat/water, (A) fan starts, igniter clicks, fires up for about 5 secs, cuts out,repeat from (A) 5 times then locks out. Resets repeats from (A).
Gas safe eng called. Removes front cover, removes inner cover, removes and cleans condensate trap, checks other things, switches on and boiler fires up and runs ok. Fits inner cover, checked gases all well within limits. Fits front cover, switches off then on repeat from(A) above. Removes both covers, switches on and boiler fires ok. So boiler works ok if switched on with inner cover off, then fitted but not if inner cover on. After2 hours engineer left scratching head to go to another appt.
any ideas please?

 

[Stadan20]

Yeah get a different engineer

 

[ianmcd]

A decent engineer will sort that in 30 mins, we all know what it is but it constitutes Gas work which site rules prohibit us from advising on, DO NOT be tempted to run the boiler with the inner combustion cover removed