Fasteners
(4) *Fasteners
*Identical fasteners on opposing side must also be loosened.
Figure 11
11.Belt tension can be adjusted by loosening four fasteners on the drive frame, see Figure 11. The motor plate slides on the slotted adjusting arms and drive frame angles in the same manner.
12a. Sizes
Note: Belts should have a slight bow on the slack side while running at full load (see Figure 12a).
Deflection
Slack
Side
Figure 12a | Figure 12b |
12b. Sizes
13.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.
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: G / GB
1.Before starting up or operating fan, check all fasteners for tightness. In particular, check the setscrews 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.
IMPORTANT
Adjust (tighten) belt tension after the first
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 GB unit only, inspect belt alignment and tension. Adjust and tighten as necessary.
Maintenance: G / 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
®
Model G/GB Centrifugal Roof Exhaust Fans 7