FV-11VQ3 panasonic fan is not working properly. we have just installed the fan and even if we

Question

we have just installed the fan and even if we stand underneath it and blow smoke into the fan, it sucks air very lightly - something clearly is not done right during the installation

I called panasonic and they said to take a look at the damper to make sure it is opening, as well as the ventilation flaps on the outside

but he said in order to get to the damper I have to remove the unit - is there an instruction guide a how to - or will I find it straight forward - if you could let me know I would really appreciate it