Sakura COOLING ONLY Installation, Operation & Maintenance Manual - page 7
Refrigerant Piping
DANGER
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Do not charge oxygen, acetylene or other flammable and poisonous gases into the refrigerant cycle when
performing the leakage test or an air-tight test. These types of gases are extremely dangerous and can
cause an explosion. It is recommended that compressed air, nitrogen or refrigerant be used for these types
of tests.
Evacuation and Refrigerant Charge
Tools and Instruments – Vacuum pump, High and Low Pressure Compound Gauge, refrigerant cylinder
with sufficient R-22, Weighing Scale, Refrigerating Oil (if required), Charging Hose
Preparation – Confirm the required amount of refrigerant, arrange piping connection work for evacuation
and refrigerant charge, as shown in fig. below.
Evacuation Procedures – Before charging refrigerant, the entire refrigeration cycle must be completely
evacuated and dehydrated. Connect the high pressure compound gauge to the high pressure check joint at
the compressor discharge side, and the low pressure compound gauge to the low pressure check joint at
the compressor suction side. Connect the vacuum pump to the service joint of the unit liquid stop valve
1. Operate the vacuum pump to perform primary evacuation of the piping and the unit.
2. Slowly open the liquid outlet stop valve and the gas inlet stop valve. Ensure that the unit is being
evacuated by checking both gauges.
3. Continue vacuum pump operation until the pressure indication on the gauges shows approximately
755 mmHg (0.67 Kpa).
4. Stop the vacuum pump, waited for approximately 5 minutes and confirm that the vacuum pressure
has not increased. Close the vacuum pump connection line.
Refrigerant Charge – change the vacuum pump with the refrigerant charging cylinder on the weighing
scale.
1. Purge air from the refrigerant charging cylinder connection line.
2. charge liquid refrigerant as required into the refrigerant cycle by weighing the refrigerant
charging cylinder.
3. After all evacuation and charging work, tighten the cap nuts for the unit stops valves.
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