Bearing Problems:
Generally speaking, Twin City Fan & Blower uses three
types of bearings:
1. Ball bearing with set screw lock.
2. Spherical roller bearings with set screw lock.
3. Spherical roller bearings with adapter lock/taper lock
feature to attach them to the shaft.
Ball bearings – These are self-aligning bearings and
should present no alignment problems with one excep-
tion: i.e., on Sealmaster bearings there is a pin beneath
the grease fitting which prevents the bearings outer race
from rotating. Should this pin jam, the bearing loses its
alignment feature.
Common failure causes are (1) set screws loosening
and shaft turning within the bearing, and (2) crowned
bearing supports. Loosen one bolt and measure the
clearance between the pillow block and the support.
Add shim to compensate.
Spherical Roller Bearings with Set Screw Lock – The
self-aligning characteristic of these bearings are inherent
in the spherical roller design. The closer that these bear-
ings are to perfect alignment, the cooler they will operate.
Common failure causes are the same as with ball
bearings, mainly set screws loosening and crowned
bearing supports.
Spherical Roller Bearings with Adapter Lock – Again,
the self-aligning feature is inherent in the spherical
design. Good alignment results in a cooler operating
bearing. The faster the bearing operates the more criti-
cal this becomes.
A common cause of failure is improper installation
practice. Removing too much clearance from the bearing
can result in preloading the bearing, resulting in prema-
ture failure; and removing not enough can result in the
shaft rotating within the bearing. Properly tightened, this
method of attaching a bearing to a shaft is second only
to a press fit. Crowned bearing supports can also pre-
load these bearings and should be checked by loosening
one side of the bearing and checking for clearance.
Lubrication – The major cause of bearing failure is
contamination of grease, insufficient grease, or incompat-
ibility of grease. If a fan is to be stored for any length
of time at the job site, the bearings immediately should
be filled with grease while rotating the shaft and then
the bearings should be regreased and rotated monthly.
This will prevent moisture, which condenses within the
bearing, from corroding the raceways. Most greases
used on fan pillow blocks are lithium base. Use the
greases shown on the bearing decal. Do not mix the
bases without completely purging out the initial grease.
Initially, follow the lubrication instruction on the side
of the fan. The frequency of lubrication should be
adjusted depending on the condition of the old grease
being purged. This is the responsibility of the user. If
the grease is dirty, the lubrication frequency should be
more often.
a. Noise – If a bearing is increasing in noise intensity
and/or vibration, it will probably result in failure.
b. Temperature – If a bearing temperature begins to
gradually rise, it will generally result in failure. A
bearing can operate up to 200 degrees and operate
satisfactorily if the temperature remains constant and
the bearing receives adequate lubrication. Remember
that a roller bearing under the same load and speed
will be somewhat more noisy and run warmer than a
ball bearing. This is normal.
Rough handling and/or dropping a fan can result in bri-
nelling the bearing. This appears as a clicking noise at
first, then gradually worsens until failure.
When replacing a bearing, always align the bearings
first, then bolt the pillow blocks to their support, rotate
the shaft, fasten the bearings to it. If the bearing is
fastened to the shaft first, tightening the pillow block
bolts may bind the shaft and preload the bearings.
Limitation of Warranties and Claims
Seller warrants to the original purchaser that the goods
sold hereunder shall be free from defects in workman-
ship and material under normal use and service (except
in those cases where the materials are supplied by the
buyer) for a period of one year from the date of original
installation or eighteen (18) months from the date of
shipment, whichever occurs first. The liability of seller
under this warranty is limited to replacing, repairing, or
issuing credit (at cost, F.O.B. factory and at seller’s
discretion) for any part or parts which are returned by
buyer during such period provided that:
a. seller is notified in writing within ten (10) days fol-
lowing discovery of such defects by buyer, or within
ten (10) days after such defects should reasonably
have been discovered, whichever is less;
b. the defective unit is returned to seller, transportation
charges prepaid by buyer.
c. payment in full has been received by seller or said
products; and
d. seller’s examination of such unit shall disclose to its
satisfaction that such defects have not been caused
by misuse, neglect, improper installation, repair,
alteration, act of God, or accident.
e. seller cannot guarantee sound pressure levels or
dBA.
No warranty made hereunder shall extend to any seller
product whose serial number is altered, effaced or
removed. Seller makes no warranty, express or implied,
with respect to motors, switches, controls, or other
components of seller’s product, where such components
are warranted separately by their respective manufac-
turers. THIS WARRANTY IS EXPRESSLY IN LIEU OF
ALL OTHER WARRANTIES, EXPRESS OR IMPLIED,
WHETHER STATUTORY OR OTHERWISE, INCLUDING
ANY IMPLIED WARRANTY OF MERCHANTABILITY OR
FITNESS FOR A PARTICULAR PURPOSE. In no event
shall seller be liable to buyer for indirect, inciden-
tal collateral, or consequential damages of any kind.
(BUYER’S FAILURE TO PAY THE FULL AMOUNT DUE
WITHIN SIXTY (60) DAYS OF DATE OF INVOICE SHALL
OPERATE TO RELEASE SELLER FROM ANY AND ALL
LIABILITY OR OBLIGATION ARISING PURSUANT TO
ANY WARRANTY, EXPRESS OR IMPLIED, WHETHER
STATUTORY OR OTHERWISE, INCLUDING ANY IMPLIED
WARRANTY OR MERCHANTABILITY OR FITNESS FOR
A PARTICULAR PURPOSE, MADE IN CONNECTION
WITH ANY CONTRACT FORMED HEREUNDER. BUYER
AGREES THAT SUCH FAILURE TO PAY SHALL
CONSTITUTE A VOLUNTARY WAIVER OF ANY AND ALL
SUCH WARRANTIES ARISING PURSUANT TO SUCH
CONTACT.)
15MWG06/14
TWIN CITY FAN & BLOWER | WWW.TCF.COM
5959 Trenton Lane N | Minneapolis, MN 55442 | Phone: 763-551-7600 | Fax: 763-551-7601
