Ariston 23 MFFI combi Hot Start Problem

[croydoncorgi]

The APS is not sticking.
What's happening is that hot air is less dense than cold air, so the venturi (which develops the vacuum that operates the APS) works less efficiently, so the APS fails to operate until the boiler has cooled a bit.
The venturi needs cleaning but this is a CORGI job. You've been in CORGI territory for a while already so I can't advise you further. It would probably be cheaper (and certainly quicker) to get it fixed properly than to mess with it yourself.

 

[parky]

Being an electrical engineer I was happy to fault find all the while the problem appeared electrical, but if this leads me anywhere near the gas bit of the boiler then that is the point I happily step down and let the experts in.

You explanation (croydoncorgi) sounds reasonable (from my 'O' level physics days) so its time for a service to get the venturi looked at.

thanks for all your help everyone

 

[ChrisR]

Went to one of these which had been "serviced by Ariston" a few days before, but I reckon the case had NEVER been off the combustion chamber, let alone recently. It's a bloudy awful design. they glue the things together instead of using foam like everyone(?) else. Fan was fluffy which gave startup problems.