Bearing Lubrication Schedule; Wheel, Fasteners And Set Screws; Variable Frequency Drive Operation; Removal Of Dust And Dirt - Greenheck TCB Series Installation, Operation And Maintenance Manual

Bearing Lubrication Schedule

Shaft bearings are the most critical moving part of a fan.
Therefore, special attention should be given to keeping
the bearings clean and well lubricated. Proper lubrication
provides for reduction in friction and wear, transmission
and dissipation of heat, extended bearing life and
prevention of rust.
In order for a lubricant to fulfill these tasks, the proper
grease applied at regular intervals is required. See
bearing manufacturer's instructions or label on the fan
housing for lubrication schedule.
In a clean environment and temperature above 32ºF
(0ºC) and below 200ºF (93ºC), fan shaft bearings with
grease fittings should be lubricated semi-annually using
a high quality lithium based grease. If unusual conditions
exist (temperatures below 32°F or above 200°F),
moisture or contaminants - more frequent lubrication is
required. Lubricate bearings on UL 762 fans with high
temperature grease conforming to NLGI Grade 2,
such as Mobil Mobilith SHC 100 or 200.
With the unit running, add grease very slowly with a
manual grease gun until a slight bead of grease forms
at the seal. Be careful not to unseat the seal by over
lubricating or using excessive pressure. Bearings without
grease fittings are lubricated for life.
Fasteners attaching the bearings to the drive frame
should also be checked.

Wheel, Fasteners and Set Screws

Wheels require very little attention when exhausting clean
air, however, air heavily laden with grease or dirt will tend
to accumulate on the wheel causing unbalance. Wheels
exhausting dirty or grease-laden air require frequent
cleaning to assure smooth and safe operation.
All fasteners, including set screws in the bearing collars,
should be checked for tightness each time maintenance
checks are performed. Particular attention should be paid
to set screws attaching the wheel to the shaft and the
shaft to the bearings. Loose bearing set screws will lead
to premature failure of the fan shaft.
A proper maintenance program will help preserve the
performance and reliability designed into the fan.

Variable Frequency Drive Operation

For operation with variable frequency drive (VFD),
always check motor amps when adjusting the operating
frequency. Motor may be sized for the original selected
operating speed under 60 Hz. Bypassing the VFD or
increasing the speed from this original selection, even
if less than 60 Hz, may cause motor to overload or fail.
Consult factory with fan serial number, before increasing
the upper limiting frequency.
Always check the fan rpm when adjusting the operating
frequency. Do not exceed maximum class fan rpm of the
wheel.
®

Removal of Dust and Dirt

Dirt clogs cooling vents on the motor housing,
contaminates bearing lubricant, and collects on the
impeller causing severe imbalance if left unchecked.
The exterior surface of the motor and impeller should be
thoroughly cleaned periodically. Use caution and do not
allow water or solvents to enter the motor or bearings.
Under no circumstances should motors or bearings be
sprayed with steam or water.

Cleaning Internal Components

Entire wheel should be cleaned during routine duct
cleaning. Partial cleaning may result in an unbalanced
wheel that can cause premature bearing failure or
excessive vibration.
Grease / cleaning solution should drain freely
through the provided drain connection. Remove any
obstructions inhibiting proper drainage.
Only the access door is removed during routine duct
cleaning. The bearing cover is not removed during
routine cleaning. The bearing cover is removed only
when inspecting or changing the bearings, fan shaft or
driven pulley.

Damper Inspection and Service,

Model TCBRU Level 1 or 2
Butterfly dampers should be inspected for proper
operation at each service interval. Check for freedom of
movement and general condition of the damper blades
and hinge rods.
Tubular Centrifugal Fans 13