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NOTE: Low voltage connector may be removed for easy installation.
Fig. 12 — Low Voltage Field Wiring
PRE-START-UP
System Checkout —
follow the system checkout procedure outlined below before
starting up the system. Be sure:
1. Voltage is within the utilization range specifications of the
unit compressor and fan motor and voltage is balanced
for 3-phase units.
2. Fuses, breakers and wire are correct size.
3. Low voltage wiring is complete.
4. Piping and system flushing is complete.
5. Air is purged from closed loop system.
6. System is balanced as required. Monitor if necessary.
7. Isolation valves are open.
8. Water control valves or loop pumps are wired.
9. Condensate line is open and correctly pitched.
10. Transformer switched to lower voltage tap if necessary.
11. Blower rotates freely — shipping support is removed.
12. Blower speed is on correct setting.
13. Air filter is clean and in position.
14. Service/access panels are in place.
15. Return-air temperature is 40 to 80 F for heating and 50 to
110 F for cooling.
16. Air coil is clean.
17. Control field selected settings are correct.
AIR COIL — To obtain maximum performance, the air coil
should be cleaned before starting the unit. A ten percent
solution of dishwasher detergent and water is recommended
for both sides of the coil. Rinse thoroughly with water.
Airflow and External Static Pressure —
50HQL,VQL units are available with standard, low, and high-
static factory-installed options. These options will substitute a
different blower drive sheave for each static range. In addition,
certain static ranges may require the optional large fan motor.
SHEAVE ADJUSTMENT — The 50HQL,VQL units are
supplied with a variable sheave drive on the fan motor to adjust
for differing airflows at various ESP (external static pressure)
conditions. See Tables 6-16 for unit airflows. When fully
closed, the sheave will produce the highest static capability
(higher rpm). To adjust sheave position, follow the procedure
outlined below:
1. Loosen belt tension and remove belt.
2. Loosen set screw on fan motor.
3. Open sheave to desired position.
When the installation is complete,
AQUAZONE CONTROL (Complete C Control Shown)
Fig. 13 — Typical Aquazone™ Control Board
Fig. 14 — Typical Aquazone Accessory Wiring
4. Retighten set screw and replace belt.
NOTE: Set belt tension as outlined below.
BELT TENSION ADJUSTMENT — An overly loose belt
will, upon starting motor, produce a slippage "squeal" and
cause premature belt failure and or intermittent airflow. An
overly tight belt can cause premature motor or blower bear-
ing failure. To adjust the belt tension, follow the procedure
outlined below:
1. Remove belt from motor sheave.
2. Lift motor assembly.
3. Loosen the
ment bolts (2 per bolt). To increase the belt tension loosen
the top hex nut. To decrease the belt tension loosen the
bottom hex nut.
4. Turn the bolts by hand to the desired position then tighten
the
5
/
-in. hex nuts (2 per bolt).
16
5. Lower the motor assembly.
6. Install the belt.
7. The belt tension can be adjusted by using one of the fol-
lowing methods:
The
a. Tighten until belt deflects approximately
with very firm finger pressure.
b. Grasp belt midway between two pulleys and twist
for a 90-degree rotation.
NOTE: Adjusting less than 90 degrees will over-
tighten the belt and adjusting more than 90 degrees
will loosen belt.
c. Set proper belt tension to 70 to 80 lb.
NOTE: The motor position should not need adjustment. Motor
sheave position is at mid position of each sheave. For example,
the motor sheave is 2.5 turns open on a 5-turn sheave. The belt
tension adjustment can also be accomplished by turning the
5
/
-in. hex nuts to the desired position.
16
NOTE: Available airflows for all units are shown in
Tables 6-16.
24
a50-6268tf.tif
Jumper Locations
TERMINAL STRIP P2
C
TYPICAL
WATER
24 VAC
VALVE
A
(Control D Shown)
5
/
-in. hex nuts on the grommet motor adjust-
16
1
/
-in.
2
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Troubleshooting
