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Adjustment during Operation
(2) Refrigerant quantity adjustment
1. Shortage of refrigerant (when charging additional refrigerant)
● Perform cooling operation and charge additional refrigerant from the low pressure service port.
● Adjust valve opening during slow charging operation to avoid frosting beyond the refrigerant service valve.
● Guideline of charging rate of refrigerant is 20 g per 5 sec.Rapid charging forces liquid slugging by the
compressor and may lead to a failure.
2. Overcharging of refrigerant (when releasing the refrigerant)
● Release the refrigerant from the low pressure service port.
● Open the valve very slowly. Use caution for oil leak out. (Release refrigerant slowly to avoid oil leak out)
● As CO
refrigerant is heavier to air, use caution for gas stagnation.
2
3. After completing refrigerant adjustment, close the low pressure service port.
Caution
When charging refrigerant, refer to the Engineering Service Manual "Refrigerant Charging Procedure".
About Alarms
Installation of an Alarm System
This refrigeration unit has a variety of protection devices for securing safety. When the ground fault protector or other
protection device is activated, and the alarm system or temperature control system is insuffi cient, cooling operation is
stopped for many hours thereby damaging the food items.
To enable prompt actions at such time, an alarm system or temperature control system should be considered at the
time of plan development.
External Alarms
This refrigeration unit is capable of delivering alarm output during abnormality (no voltage contact: contact capacity
240 V AC 3A).
During unit abnormality, the alarm output between the control terminals 9 and 10 is turned ON (continuity between
the contacts). Connection of an external alarm circuit (local wiring) is recommended. External alarm power should be
furnished separately from the refrigeration unit power.
Detail of abnormality alarm content is shown in the table below.
Buzzer stopping switch
9
10
Buzzer
BZ
EN - 38
External alarm power
(220
240 V AC)
~
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