Upblast Centrifugal Roof Exhaust
8
Maintenance
DANGER
Disconnect and secure to the “off” position all
electrical power to the fan prior to inspection or
servicing. Failure to comply with this safety precaution
could result in serious injury or death.
WARNING
This unit should be made non-functional when
cleaning the wheel or housing (fuses removed,
disconnect locked off).
DANGER
Pour écarter les risques de blessure grave ou de mort,
débrancher et verrouiller l’alimentation électrique en
position « Arrêt » avant tout contrôle ou entretien.
AVERTISSEMENT
L’appareil doit être rendu non opérationnel lors du
nettoyage de la turbine ou du caisson (fusibles retirés,
sectionneur verrouillé).
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
belt drive unit only, inspect belt alignment and tension.
Adjust and tighten as necessary.
Operation
1. Before starting up or operating fan, check all
fasteners for tightness. In particular, check the
setscrews in the wheel hub (or the tapered bushing
and pulleys if applicable).
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, reference Figure 13.
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.
IMPORTANT
Adjust (tighten) belt tension after the first 24-48 hours
of operation.
9. The adjustable motor pulley is factory set for
the RPM specified. Speed can be increased by
closing or decreased by opening the adjustable
motor pulley.
10. Any increase in speed represents a substantial
increase in the horsepower required by the unit.
11. Motor amperage should always be checked to
avoid serious damage to the motor when speed
is varied.
IMPORTANT
The fan has been checked for mechanical noises at
the factory prior to shipment. If mechanical noise
should develop, suggested corrective actions are
offered in the Troubleshooting section.
IMPORTANT
Over tightening belts will cause excessive bearing
wear and noise. Too little tension will cause slippage
at startup and uneven wear.
7. Belt tension can be adjusted by loosening four
fasteners on the drive frame, see Figure 16.
The motor plate slides
on the slotted adjusting
arms and drive frame
angles in the same
manner.
Four (4) fasteners in
total.
Identical fasteners on
opposing side must
also be loosened.
8a.
Sizes 099-161:
Belts should be tensioned just
enough to prevent slippage at full load. Belts
should have a slight bow on the slack side while
running at full load; see Figure 17a.
8b.
Sizes 180-480:
Belt tension should be adjusted to
allow 1/64 in.
(0.397 mm)
of deflection per inch of
belt span. For example, a 15 in.
(381 mm)
belt span
should have 15/64 in.
(5.95 mm)
(or about 1/4 in.
(6 mm)
) of deflection with moderate thumb pressure
at mid-point between pulleys, see Figure 17b.
Figure 16
Slack
Side
Figure 17a
Figure 17b
