Greenheck Downblast Centrifugal Roof Exhaust GB-420

Disconnect and secure all electrical power to the fan

Ensure the unit is made non-functional (fuses removed, disconnect locked off)

Verify that only qualified personnel are performing the maintenance

Clean exterior surfaces of the motor

Remove dust buildup on motor housing to ensure proper cooling

Ensure cleaning is even to prevent out of balance condition

Fasteners and Setscrews Inspection

Check all fasteners and setscrews for tightness

Does the wheel rotate freely and is it aligned as shown in Figure 7?

Was the wheel position verified for movement during shipment?

Was the centering height alignment adjusted by loosening the set screws and moving the wheel?

Disconnect all electrical power to the fan and secure to the 'off' position

Remove fuses and lock off the disconnect

Check for oil and dust accumulation on the wheel and housing

Clean the wheel evenly to prevent imbalance

Is the wheel balanced after cleaning?

Disconnect all electrical power to the fan and secure to the 'off' position.

Ensure the unit is made non-functional by removing fuses and locking off the disconnect.

Are grease fittings provided on the motor?

Replace grease in motors where temperatures do not exceed 104ºF (40ºC) after 2,000 hours of running time.

Verify the following are in place after maintenance

Is the fan operating without vibration?

Loosen the setscrew holding the bushing and shaft key in place, if present.

Loosen and remove the socket head cap screws fastening the bushing to the hub.

Select the mounting type for socket head cap screws installation

Tighten the socket head cap screws an eighth of a turn at a time, alternating until the hub comes loose from the bushing.

Clean all surfaces of hub and bushing to remove any oil or residue.

Select the mounting style for bushing installation

Use the keyway setscrew to hold the shaft key and bushing in place, if present, without overtightening.