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NOTE:
A quick and easy way to run the fans and compressor is by using
the dap4, MENU I
– MANUAL CONTROL (Service Level). See dap4 IOM
instructions for details. All automatic control is disabled but safety
switches will remain functional.
5.7.1.2.
Charge Fixed Speed Compressor
Before turning the system ON to finish charging the circuit, make sure to check for voltage
phasing. For more information on this refer to section
NOTE:
Charging to a full liquid line sight glass should never be the sole
means of determining the correct refrigerant charge. Other parameters
such as superheat, suction pressure, head pressure, sub-cooling and
ambient temperature are also important. A system charged to a clear
sight glass is often overcharged.
If equipped with two circuits, temporarily disable the Variable Speed Compressor by setting the
Variable Frequency Drive (VFD) in the OFF condition or by removing the fuses to prevent this
compressor from starting during the charging of the fixed speed compressor.
Start the system by using the setpoint under Menu B
– Setpoints. The unit must be started in
the normal operating mode based on a call for cooling required by the dap4 controller once an
initial charge has been added to the circuit. Before starting the system, make sure pressure
gauges and suction line temperature sensor are hooked up and refrigerant readings are aligned
with EEV reading.
If the unit is in OFFbyKEY position, hold the ESC key for 5 seconds to start the system via the
dap4 controller. Allow time for all fans to start and for the system to stabilize to room temperature.
Bubbles in the sight glass are not unusual at this point. It is likely that more refrigerant will be
required to complete the charging procedure.
Finish charging by slowly opening the valve on the refrigerant manifold set to meter liquid
refrigerant into the low side of the system. Use a liquid charging adapter to prevent liquid
refrigerant from entering the compressor.
Adjust the refrigerant charge to the sub-cooling value shown in the table below and the sight
glass has sparse bubbles. The unit should be allowed to stabilize for 15 to 20 minutes to verify
key measurements in the table below.