Buzzing noise from dimplex fcxa storage heater when switched to boost?

Had a look at an FCXA this morning with the same fault. Its not the fan as I cleaned and checked this.
It appears to be a small solenoid or switch 'chattering' on the PCB behind the electric termination panel on the RHS of the heater, next to the fan.
I have tried cleaning out the solenoid contacts and the pcb in general, but its not made any difference. I think it would need a replacement PCB, sadly, and I dont think I'll find one anywhere.

The Maintenance Man
February 2021

Ha, sorry! Just read that the fan is running(?); is it spinning at full-chat? If you impede a motor's ability to rotate then it would hum.

It needs investigating, but it still sounds to me like it's the motor.

Steve Edwards
April 2012

The convection (boost) fan is stuck; probable cause is the bushes are clogged with fluff, therefore the fan motor cannot run. It will overheat if not serviced.

Steve Edwards
April 2012