Unusual boiler trip 24i junior?

[Knappers]

I've got an issue with an ageing worcester 24i junior.
It seems to run fine but often trips RCD just after using HW.
I couldn't find an issue but checked and cleaned all contacts and checked terminations in socket and plug (it is a caravan if that makes a plug ok IDK?)

It's definitely intermittent but after insisting they get wiring checked they've come back with a full bill of health and a video showing it run in HW mode and then trip apx 6 seconds after burner goes out?

Any ideas....pls.....?

 

[ShaunCorbs]

Hw leaking onto hw micro switch

 

[Deleted member 120897]

Hw leaking onto hw micro switch

Flow turbine one?

 

[Knappers]

Flow turbine one?

Yea, bithermal hex and turbine sensor....

 

[Knappers]

I'm between fitting a new pcb or idk...- plugging into an isolation transformer?

 

[Knappers]

Maybe it's one to pass off to worcester 🤷‍♂️