In message , Harry Bloomfield
writes
raden explained :
I sold someone a fan for his CH boiler a couple of months ago and he
swears that it causes RF interference. I sent him another one which
he says is OK. We've also changed his pcb for him (to eliminate the
possibility of it being a relay problem

Now given the fact that it's a shaded pole motor and the connections
to it are sound (i.e. electrically, it's just a coil of wire) does
anybody have an explanation ?

None... Except the connections were not in fact tight, or a fault on
the PCB.

Changed the pcb, checked the fan ctrl relay first

swapped the fan over several times

The fan works without generating RF when back at the factory

It's only when it's in the boiler

--
geoff