Extractor fan vent exit flaps not opening when extractor fan is on

[Rotor888]

When the extractor fan in the ensuite bathroom is on, the flaps on the vent outside don't open. Why is this?

 

[mikehammer69]

Fan not powerful enough
Or long run of ducing not pulled tight
Or friction or maybe stuck. Have you checked it to see what's wrong.

 

[Murdochcat]

Insufficient air flow under the door into the bathroom - which means the fan can’t push any air out

Has it ever worked properly

 

[Rotor888]

Fan not powerful enough
Or long run of ducing not pulled tight
Or friction or maybe stuck. Have you checked it to see what's wrong.

I think there could be a long run of ducting