Downdraft Ventilation System: Why doesn't the downdraft vent fan pull much air?

When the downdraft vent fan isn’t pulling much air, clogged grease filters, air duct problems, a fan motor failure or a broken blower wheel could be causing poor air suction.

First, check the condition of the grease filters and wash or replace them if dirty.

Next, check the air damper on the vent duct cap attached to the outside of your house. That air damper keeps outside air from flowing into your home when the downdraft vent fan isn’t running. Repair or replace the air damper if it doesn’t open to allow downdraft exhaust air to flow out of the exhaust duct.

Check the blower wheel for damage because a damaged blower wheel won’t move air through the downdraft vent properly. Replace the blower wheel if damaged.

A weak fan motor won’t turn the blower wheel at the right speed to move air through the downdraft vent. If the fan motor makes noise or doesn’t turn the blower wheel at full speed when activated, replace the fan motor.