61OCH0006F08/13/2024
CEILAIR
®
CW & DX IOM
2.10.7 HOT GAS REHEAT OPTIONAL
6. Adjust the blower speed by closing the sheave one half turn to increase speed or opening the sheave one
half turn to decrease speed.
7. Replace the sheave key and tighten the set screw.
8. Proper belt tension is achieved when the belt has a deflection of 1/2 in per foot of span between the
blower and motor pulleys when a firm pressure is placed on the side of the blower belt. Adjust the blower
belt tension by raising (to tighten) or lowering (to loosen) the nuts on the adjustment rods of the motor
base.
CAUTION
If the belt tension is too tight, it will cause premature blower or motor bearing failure. If the belt is too
loose, the belt will slip and cause belt squeals and eventual belt failure.
9. Restore power to the system.
10. Check the current draw on the blower motor to make sure it does not exceed the nameplate rating of the
motor.
11. If the current draw exceeds the nameplate rating of the motor, repeat steps one through nine to decrease
blower speed. If the motor pulls too much current, slow the blower down by opening the adjustable
sheave one half turn at a time until the motor current is at or below the nameplate FLA.
12. Check the motor overload on the blower starter to confirm its setting is correct for the FLA of the motor.
2.10.5.2 EC Fan (Optional)
The speed of the EC fan is controlled via a 0 to 10 V DC signal from the system controller. The controller is set
by the factory and should not require adjustment. If it is determined that the airflow needs adjustment, this
may be done using the controller’s programming menu selections. Refer to the operator’s manual provided
separately for the system controller.
2.10.6 Thermal Expansion Valve
CeilAir units using DX refrigerant have a thermal expansion valve (TXV). The TXV maintains constant
superheat of the refrigerant vapor at the inlet of the evaporator by metering the flow of refrigerant into
the evaporator. Superheat is the difference between the refrigerant vapor temperature and its saturation
temperature at a given suction pressure. By controlling superheat, the TXV keeps nearly the entire evaporator
surface active while preventing liquid refrigerant from returning to the compressor. As a standard, superheat
is factory set at 1215 °F and should not need adjustment.
2.10.7 Hot Gas Reheat (Optional)
The hot gas reheat feature incorporates a hot gas reheat solenoid valve and a hot gas reheat coil. Under
normal operation when no reheat is required, the hot gas reheat valve is de-energized and hot gas flows
directly from the compressor discharge to the condenser. When there is a call for reheat, the controller
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