Satronic MMI panel locking out on white

[bright spark]

Hi lads, I have Riello RS 28 gas burner locking out at the white part of the disc at the very beginning of its cycle. You know the disc I'm on about where the different stages of the burners operation are so that you have an indication of what stage the burner broke down at.
Anyway while checking out the burner, I saw I on one occasion cycle around without starting or locking out. Check with satronic literature to indicate air pressure switch may be faulty. So I've changed the pressure switch. Anyone every see the panel lockout on white before.

 

[bright spark]

Was talking to Malcolm in Satronic technical. He reckons it's dampness. It only goes to lockout at start of week. Boiler house is outside and very cold in midlands of Ireland. Have changed ionisation lead and probe. C what happens monday

 

[Dotty]

Not had that.

Flame probe, ignition electrode, transformer or gas valve. Not an APS yet.

 

[Dotty]

That's their usual response when they don't know haha

 

[bright spark]

Ah sure croppie keeps life interesting.