140.925-IOM (APR 2019)
Page 25
XLP3 EVAPORATIVE CONDENSERS
MAINTENANCE
•
Rotation:
Turn the fan by hand to ensure that it moves
freely with no rough spots, binding, or other malfunctions
that could cause vibration or fan motor overload. While
rotating the fan, check the blade tracking. All blades should
track within a 1/2” band at any single point around the
cowl.
•
Direction of Rotation:
On initial start-up, or if the fan
motor has been rewired, briefly energize the fan motor
and note the direction of rotation. It should rotate in the
direction indicated by the arrow on the fan cowl. On units
with independent fan motors, check the rotation of each
fan.
•
Operation:
On initial start-up, run the fan in the manual
position for several minutes, and check for any unusual
noises or vibrations.
NOTICE
Check to ensure the controls for the fan motor are set to
allow a maximum of six on-off cycles per hour to prevent
motor overload.
Drive System Inspection & Maintenance
The Belt Drive Fan System requires a periodic check of the belt
condition and, when necessary, tension adjustment. The recom-
mended service intervals are as follows:
•
Initial Start-up
:
•
Externally Mounted Motor:
The motor base assembly
has been pre-aligned at the factory. Mount the motor
base assembly to the unit and verify alignment. Install
the belt and follow the belt tensioning directions below.
•
Seasonal Start-Up:
Readjust the belt tension (if
required).
•
Operation:
After the first 24 hours of operation, readjust
the belt tension on a new unit start-up or installation of a
new belt. Thereafter, check the belt condition monthly, and
adjust tension as necessary. Readjust tension at least once
every three months.
•
Belt tension check:
• Place a straight edge along the belt from sheave to
sheave as shown in Figure 22a, or use a tape measure
as shown in Figure 22b to measure belt deflection.
• Apply a moderate force by hand (approximately 40
lbs/275 kPa) evenly across the width of the belt in the
center of the span between the sheaves.
• There is adequate belt tension if the belt deflects
between 1/4” and 3/8” as shown in Figures 22a and 22b.
Figure 22a — Belt Tension with a Straight Edge
Figure 22b — Belt Tension with a Tape Measure
•
Belt tension adjustment (if required)
:
• Using a wrench or impact gun, turn the motor base
adjusting screw (Figure 23) clockwise to tension the
belt or counterclockwise to relieve belt tension. During
adjustment of the belt tension, rotate the drives
several times by hand to evenly distribute the tension
throughout the belt.
Figure 23. Motor Adjusting Screw
Motor
Adjusting
Screw
NOTICE
If belts are properly tensioned, there should be no “chirp”
or “squeal” when the fan motor is started.
• Drive alignment check and adjustment:
• Place a straight edge across the driver and the driven
sheaves as shown in Figure 24.
• The straight edge should contact all four points as
shown in Figure 24 indicating that the drives are
properly aligned.
• There should be no more than 1/16” deviation from the
four points of contact.
• In case of realignment, loosen the driver sheave, and
align it with the driven sheave. Allow 1/4” for draw-up
as the bushing screws are retightened.
DANGER
Rotating equipment will cause severe personal injury or
death to persons who come in contact. Do not perform any
service on or near the fans, motors, and drives, or inside the
unit without first ensuring that the fans and pump motors
are disconnected, locked out, and tagged out.