Fitting the Flowerpot one way air valve

Cut wire two or three sections back, and pull the cut wire out of the plastic. this makes it easer to wrap the flexi pipe over the end of the connecting ring,made mine from the lid of the tin, but had to crease it to fit inside. I pushed the end of the flexi pipe through the ring and folded the end back before pushing into the pipe and held it in place with cloth tape. i also taped the pipe to the fan.
Make sure you en-line the hinge at the top top of the flap with the top of the fan or the flap will stay open.

Step 1 Fixing the fan

 Push the flei pipe through the wall and feed the cable through the fan, mark the fixing points, drill holes and fix with screws and plugs. 
this fan was double insulated so the earth wire was redundant, so the instructions said to wrap earth wire to a plastic tag.
the power for the fan was switched via the light pull switch through a fuse spur with a 5amp fuse.