Trane Precedent THC036E, Installation And Maintenance Manual

Page: 49 / 64

RT-SVX22J-EN 49
Maintenance
Fan Belt Adjustment - Belt Drive
Units
The fan belts must be inspected periodically 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 53, p. 49 ; adjust the belt tension as follows;
1. To determine the appropriate belt deflection;
a. Measure the center-to-center shaft distance (in
inches) between the fan and motor sheaves.
b. Divide the distance measured in Step 1a by 64; 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 tension 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.
4. Place the large end of the gauge at the center of the belt
span; then depress the gauge plunger until the large O-
ring is even with the top of the next belt or even with
a straightedge placed across the fan and motor
sheaves. Refer to
Figure 53, p. 49 .
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) required to give the needed deflection.
6. Compare the “force” scale reading ( Step 5 ) with the
appropriate “force” value listed in Table 12, p. 49 . If the
“force” reading is outside the range, readjust the belt
tension.
Note: Actual belt deflection “force” must not exceed the
maximum “force” value shown in
Figure 53, p. 49 .
7. Recheck the belt tension at least twice during the first
2 to 3 days of operation. Belt tension may decrease
until the new belts are “run in”.
Monthly Maintenance
Before completing the following checks, turn the unit OFF
and lock the main power disconnect switch open.
Filters
Inspect the return air filters. Clean or replace them if
necessary. Refer to the unit Service Facts for filter
information.
WARNING
Rotating Components!
During installation, testing, servicing and
troubleshooting of this product it may be necessary to
work with live and exposed rotating components. Have
a qualified or licensed service individual who has been
properly trained in handling exposed rotating
components, perform these tasks. Failure to follow all
safety precautions could result in rotating components
cutting and slashing technician which could result in
death or serious injury.
Figure 53. Belt tension gauge
Table 12. Belt tension measurement and deflection
Deflection Force (Lbs.)
Belts
Cross
Section Small
P.D
Range
Super
Gripbelts
Gripnotch
Steel Cable
Gripbelts
Min. Max. Min. Max. Min. Max
A
3.0 - 3.6 3 4 1/2 3 7/8 5 1/2 3 1/4 4
3.8 - 4.8 3 1/2 5 4 1/2 6 1/4 3 3/4 4 3/4
5.0 - 7.0 4 5 1/2 5 6 7/8 4 1/4 5 1/4
B
3.4 - 4.2 4 5 1/2 5 3/4 8 4 1/2 5 1/2
4.4 - 5.6 5 1/8 7 1/8 6 1/2 9 1/8 5 3/4 7 1/4
5.8 - 8.8 6 3/8 8 3/4 7 3/8 10 1/8 7 8 3/4
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.