Zephyr Savona ZSA-M90S Kitchen Hood "range flap making noise" Questions

...the butterfly flap from opening with a fixing for the flue. Also one where builder squashed the pipe in the roof. Another where there was no pipe from hood, not moving air at all,just a noise

flap valve and noise 1. The hood is shipped with a 6 inch round flap valve, presumably to keep outside air from blowing into the kitchen. The manual makes no mention of this part. Is installation ...