If the downward opening of the hood does not rise, it is possible that the hole itself is simply too small for normal draft.
If it is not possible to leave holes for ventilation (small branch duct), then you can try to increase (knock out, if brickwork) the horizontal part of the ventilation duct exhaust hole vertically. If this cannot be done, remove (do not install) the check valve on the hood (it is included in the kit), where the air duct is connected to the hood. Then the natural draft of air removal with the hood turned off will go through it constantly, albeit in a smaller volume than if the ventilation grill shown above was installed. If you need help with range hood repair San Jose, call us right now!