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System Start-Up
Figure 24 — Typical Compressor Terminal Block
Compressor Crankcase Heaters
Each compressor is equipped with a crankcase heater and is controlled by a
600 volt auxiliary switch on the compressor contactor. The proper operation
of the crankcase heater is important to maintain an elevated compressor oil
temperature during the "Off" cycle to reduce oil foaming during compressor
starts.
When the compressor starts, the sudden reduction in crankcase pressure
causes the liquid refrigerant to boil rapidly causing the oil to foam. This
condition could damage compressor bearings due to reduced lubrication
and could cause compressor mechanical failures.
When power has been "Off" for an extended period, allow the crankcase
heater to operate a minimum of 8 hours before starting the unit. Compressor
crankcase heaters can be energized by supplying 115V power to the shore
power plug (9J1) installed near the chiller control panel.
Low Ambient Damper Adjustment
(Factory or Field Installed)
A damper is factory installed over the lead condenser fan for each
refrigeration circuit. Refer to the appropriate unit illustrated in Figure 22 for
the damper locations.
The UCM has a factory default setpoint of 90°F. This setpoint can be
adjusted using the Human Interface programming procedures.
Inspect the damper blades for proper alignment and operation. Dampers
should be in the closed position during the "Off" cycle. If adjustment is
required;
1. At the Human Interface, program the actuator for 0% on circuit #1 and/or
circuit #2. (The output signal will go to 0.0 VDC.)
72
CSRA-SVX02A-EN
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