Johnson Controls ZY Series, Installation Manual

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Belt tension
About this task:
The tension on the belt should be adjusted as shown in Figure 27.
Figure 27: Belt Adjustment
CAUTION
Procedure for adjusting belt tension below:
1. Loosen the three nuts (A and B on side and C on back) of motor mount slide plate.
2. Adjust tension by placing a flat heat screwdriver into the belt tightening slots (1/4 in. x 1/2 in.) in the
motor mount slide plate and applying pressure against the motor mounting plate. See Figure 27.
3. Tighten the three loosened nuts (A, B, and C).
4. Determine the deflection distance from normal position, use a straight edge from sheave to sheave as
reference line. Use belt tension checker to apply a perpendicular force to the belt at the midpoint of
the span as shown. Deflection distance of 4mm (5/32 in.) is obtained.
5. After adjustments are completed re-tighten nuts (A, B, and C).
Altitude and temperature correction for
CFM, static pressure and power
The information below should be used to assist
in application of product when being applied at
altitudes at or exceeding 1000 ft above sea level.
The air flow rates listed in the standard blower
performance tables are based on standard air at
sea level. As the altitude or temperature increases,
the density of air decreases. In order to use the
indoor blower tables for high altitude applications,
certain corrections are necessary. A centrifugal fan
is a "constant volume" device. This means that, if
the rpm remains constant, the CFM delivered is the
same regardless of the density of the air. However,
since the air at high altitude is less dense, less static
pressure will be generated and less power will be
required than a similar application at sea level. Air
density correction factors are shown in Table 28 and
Figure 28.
INSTALLATION MANUAL ZY SERIES 3 - 10 ton 60 Hertz R-410A 82
Johnson Controls Ducted Systems