Consciot 110/160 CFM Bathroom Fan with Light

If the hole is too small, trace the housing onto the ceiling and then cut the ceiling with a keyhole saw. If the hole is too big, you'll need to patch the ceiling. Cut as piece of drywall to make the ceiling hole the right size for your fan.

Make sure you are using a non-dimmer switch and that the switch contact is good; Make sure that the cables to the light and fan are properly connected. Only works with 120V; Make sure the wire connecting the lampshade to the housing is well inserted.

Check damper to ensure it is opening & closing properly; Be sure do not have any sharp bends in duct closer than 18 in. to the fan discharge; Use recommended size ducting to reduce fan noise; Be sure the fan is securely attached to ceiling joists.

Be sure a door or window is slightly ajar or opened to allow airflow; Be sure the fan is vented with the right size duct; The deep corrugations of flexible ducting may easily flex into the opening and block the damper, please use semi-rigid ducting.

Avoid venting through a soffit vent or ridge vent. The warm air will exhaust out the duct and enter back into the attic through it; An insulated duct will help prevent condensation when the warm air from the bathroom meets the cold duct in the attic.