Do the dampers open and close freely?

With the filter removed (see Hood Cleaning Section), locate the dampers (flaps) and ensure that they open and close freely. If they do not, identify and remove any obstructions that are preventing the dampers from opening. Screws protruding through the duct work are the most common obstruction. During installation, only duct tape should be used to attach transitions or duct work to the top of the hood. Screws that are used to connect duct work and transitions extend inside the duct work and may obstruct the dampers from opening. Note: If smoke still enters the kitchen after following these suggestions, contact you dealer for additional service/suggestions.  more