6
Model H-G/H-GB Centrifugal Roof Exhaust Fan
IMPORTANT
Adjust (tighten) belt tension after the first 24-48 hours
of operation.
Inspection
Inspection of the fan should be conducted at the first 30
minute and 24 hour intervals of satisfactory operation.
30 Minute Interval
Inspect bolts, setscrews and motor mounting bolts.
Adjust and tighten as necessary.
24 Hour Interval
Check all internal components. On H-GB unit only,
inspect belt alignment and tension. Adjust and tighten as
necessary.
Maintenance: H-G / H-GB
Installation and maintenance are to be performed only
by qualified personnel who are familiar with local codes
and regulations and who are experienced with this type
of equipment.
Motor maintenance is generally limited to cleaning and
lubrication (where applicable). Cleaning should be limited
to exterior surfaces only. Removing dust buildup on motor
housing ensures proper motor cooling.
WARNING
Always disconnect, lock and tag power source before
servicing. Failure to disconnect power source can
result in fire, shock or serious injury.
Greasing of motors is only intended when fittings are
provided. Many fractional horsepower motors are
permanently lubricated and should not be lubricated
after installation. Motors supplied with grease fittings
should be greased in accordance with manufacturers’
recommendations. Where motor temperatures do not
exceed 104ºF
(40ºC)
, the grease should be replaced after
2,000 hours of running time as a general rule.
Wheels require very little attention when moving clean
air. Occasionally, oil and dust may accumulate causing
imbalance. When this occurs the wheel and housing
should be cleaned to ensure smooth and safe operation.
All fasteners should be checked for tightness each time
maintenance checks are performed prior to restarting
unit.
A proper maintenance program will help these units deliver
years of dependable service.
CAUTION
Uneven cleaning of the wheel will produce an out of
balance condition that will cause vibration in the fan.
WARNING
This unit should be made non-functional when cleaning
the wheel or housing (fuses removed, disconnect
locked off).
Belt-Bearing Maintenance H-GB Unit
1. Belts tend to stretch after a period of time. They
should be checked periodically for wear and
tightness. When replacing belts, use the same type
as supplied with the unit.
2. Matched belts should always be used on units with
multi-groove pulleys.
3. For belt replacement, loosen the tensioning device
enough to allow removal of the belt by hand.
4. Once installed, adjust belts as shown in “Pre-Starting
Checks.”
5. Shaft bearings can be classified in two groups:
relubricating and non-relubricating. All
non-relubricating bearings on standard Model H-GB
fans are factory lubricated and require no further
lubrication under normal use (between -20º to 180ºF
(-29º to 82ºC)
in a relatively clean environment).
6. On H-GB belt driven fans, the standard cast
pillow block bearings are factory lubricated and
are provided with external grease fittings. Annual
lubrication is recommended, or more frequently if
needed (see Table 2 on page 7). Do not over-grease.
Use only one or two shots of lubricant with a hand
gun. Maximum hand gun rating is 40 psi. Rotate
bearings during lubrication where good safety
practice permits. Caution should be employed to
prevent over packing or contamination.
7. Grease fittings should be wiped clean. The unit
should be in operation while lubricating. Extreme
care should be used around moving parts.
14. Any increase in speed represents a substantial
increase in the horsepower required by the unit.
15. Motor amperage should always be checked to avoid
serious damage to the motor when speed is varied.
Operation: H-G / H-GB
1. Before starting up or operating fan, check all
fasteners for tightness. In particular, check the set
screws in wheel hub.
2. While in the OFF position or before connecting the
fan to power, turn the fan wheel by hand to be sure it
is not striking the venturi or any obstacle.
3. Start the fan and shut it off immediately to check
rotation of the wheel with directional arrow in the
motor compartment.
4. When the fan is started, observe the operation and
check for any unusual noises.
5. With the system in full operation and all ductwork
attached, measure current input to the motor and
compare with the nameplate rating to determine if
the motor is operating under safe load conditions.
6. Keep inlets and approaches to fan clean and free
from obstruction.
