In article . com,
"Mike" writes:
Looks like you need to buy a new one. It's not difficult to do
yourself. they don't last forever.

Might be worth checking if the motor has failed. If so, you
might be able to buy a plain no-humidistat equivalent model,
and swap the fan motors over. This would be cheaper than
buying a humidistat fan, which come at quite a price premium.

These fan motors don't have a good track record with me.
I've had very short life from both Monrose and Delta makes.
Currently got a Wickes one and a super slim Vent-Axia one,
but both are too new to comment yet. Haven't tried Xpelair.

--
Andrew Gabriel