Precedent® RT-SVX38D-EN Rooftop Units: Periodic Maintenance

Once the new belts are installed, using a Browning or Gates tension gauge (or equivalent) illustrated in Figure 31; adjust the belt tension as follows:

• 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.

• Set the large O-ring on the belt tension gauge at the deflection value determined in Step 1b.

• Set the small O-ring at zero on the force scale of the gauge plunger.

• Place the large end of the gauge at the center of the belt span, then depress the gauge plunger until the large Oring is even with the top of the next belt or even with a straightedge placed across the fan and motor sheaves. Refer to Figure 70, p. 66.

• 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.

• Compare the “force” scale reading (Step 5) with the appropriate “force” value listed in Table 10. 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 Table 10.

• 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”.