The part(s) or condition(s) listed below for the symptom Range vent hood turns off by itself are ordered from most likely to least likely to occur. Check or test each item, starting with the items at the top of the page.
The filters in the range hood need to be clean to have good air flow. If the filters are clogged the blower will have a hard time moving air, causing the motor to overheat, and shut off. Inspect the filters and clean or replace them if necessary.
If the vent hood motor keeps shutting off the venting may be obstructed. If accessible, check the outside vent cap for a bird's nest, etc. Turn the vent hood on and check for good air flow at the inlet and outlet. If you suspect the vent is clogged, but you cannot access it, you should have someone check it for you.
The blower has a motor that can overheat and shut off. If the motor is not turning freely, or is running for awhile and shutting off, but still has power to it, the blower will need to be replaced.
If the exhaust fan motor has power to it but keeps shutting off, the windings or bearings may be bad. Try turning the fan blade by hand. If the fan blade does not turn freely, or the motor keeps shutting off when it has power to it, the exhaust fan motor will need to be replaced.
If the fan motor has power to it but keeps shutting off, the windings or bearings may be bad. Try turning the fan blade by hand. If the fan blade does not turn freely, or the motor keeps shutting off when it has power to it, the fan motor will need to be replaced.
If the blower motor windings or bearings are bad the motor may overheat and shut off. Make sure the blower wheel turns freely. If the motor doesn’t turn freely, or the motor is shutting off after it runs awhile, the motor may be bad and will need to be replaced.
If the vent fan motor is running for awhile, but then shuts off, the motor windings or bearings may be bad, causing the motor to overheat. First check to see that the fan turns freely. If the fan turns freely but the motor keeps shutting off, the motor may be bad and will need to replaced.
The blower has a motor that can overheat and shut off. If the motor is not turning freely, or is running for awhile and shutting off, but still has power to it, the blower will need to be replaced.
You can inspect the outdoor vent hood for obstructions (a bird's nest, etc.) and confirm the vent damper is operating properlty. If the air duct diameter is too small or the length of the duct is too long, the air flow will be restricted, possibly causing the vent hood to overheat and shut off. Refer to the installation instructions for proper vent size and maximum length.
Most vent hoods have a damper to help keep the outside air from migrating back into the house when the vent is not in use. If the damper is stuck closed, or not opening all the way, the air flow may be restricted causing the motor to overheat and shut off.
If the blower wheel is clogged with debris the air flow will be restricted which can cause the blower motor to overheat and turn off on it's own. You can try cleaning the blower wheel with dish soap and warm water. If the blower wheel cannot be cleaned or is damaged, it will need to be replaced.
If the fan blade is clogged with debris the air flow will be restricted which can cause the blower motor to overheat and turn off on it's own. You can try cleaning the fan blade with dish soap and warm water. If the fan blade cannot be cleaned or is damaged, it will need to be replaced.
Most vent hoods have a vent damper to help keep the outside air from migrating back into the house when the vent is not in use. If the damper is stuck closed, or not opening all the way, the air flow may be restricted causing the motor to overheat and shut off. Inspect the vent damper for an obstruction or damage and replace if necessary.
If the blower wheel or fan blade is clogged the air flow will be restricted. You can try cleaning the fan blade or blower wheel with dish soap and warm water. If the fan blade or blower wheel cannot be cleaned or is damaged, it will need to be replaced.