Trane YSC120 - Maintenance Procedures; Fan Belt Tension Adjustment

RT-SVX31A-EN34
ROTATING PARTS!
UNIT STARTS AUTOMATICALLY
Make sure all personnel are standing
clear of the unit before proceeding.
The system components will start
when the power is applied.
Fan Belt Adjustment
The fan belts must be inspected peri-
odically to assure proper unit operation.
Replacement is necessary if the belts
appear frayed or worn. Units with dual
belts require a matched set of belts to
ensure equal belt length.
When removing or installing the new
belts, do not stretch them over the
sheaves. Loosen the belts using the
belt tension adjustment bolts on the
motor mounting base.
Once the new belts are installed, using
a Browning or Gates tension gauge (or
equivalent) illustrated in Figure 9; ad-
just the belt tension as follows;
1. To determine the appropriate belt de-
flection;
a. Measure the center-to-center
shaft distance in inches or
millimeters between the fan and
motor sheaves.
b. Divide the distance measured in
Step 1a by 64 inches or 152
millimeters; the resulting value
represents the amount of belt
deflection that corresponds to
the proper belt tension.
2. Set the large O-ring on the belt ten-
sion gauge at the deflection value
determined in Step 1b.
3. Set the small O-ring at zero on the
force scale of the gauge plunger.
Maintenace
4. Place the large end of the gauge at
the center of the belt span; then de-
press the gauge plunger until the
large O-ring is even with the top of
the next belt or even with a straight-
edge placed across the fan and
motor sheaves. Refer to Figure 9.
5. Remove the belt tension gauge.
The small O-ring now indicates a
number other than zero on the
plunger’s force scale. This number
represents the force in pounds or
newtons required to give the
needed deflection.
6. Compare the “force” scale reading
(Step 5) with the appropriate “force”
value listed in Table 7. If the “force”
reading is outside the range, read-
just the belt tension.
Note:
Actual belt deflection “force” must
not
exceed the maximum “force” value
shown in Table 7.
7. Recheck the belt tension at least
twice during the first 2 to 3 days of
operation. Belt tension may de-
crease until the new belts are “run
in”.