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!
WARNING
To avoid risk of electrical shock that can cause death or severe personal injury,
disconnect unit from power before servicing unless tests require power.
10. Cooling Cycle Heavy Repair
10-3. Practical Work for Heavy Repair (continued)
Items
Precautions
3.Vacuum
degassing
Pipe Connection :
Connect a “red” hose to the high pressure side and a “blue” hose to the low pressure side.
Vacuum Sequence :
Open
①
,
②
valves and evacuate for 40 minutes. Close valve
①
.
■
KEYPOINTING
■
1) If power is applied during
vacuum degassing, vacuum
degassing shall be more effective.
2) Operate compressor while
charging refrigerant.
(It is easier and more certain
to do like this.)
4.Refrigerant
charging
Charging sequence :
1) Check the amount of refrigerant supplied to each model after completing vacuum
degassing.
2) Evacuate bombe with a vacuum pump.
3) Measure the amount of refrigerant charged.
→ Measure the weight of an evacuated bombe with an electronic scale.
→ Charge refrigerant into a bombe and measure the weight.
→ Calculate the weight of refrigerant charged into the bombe by subtracting
the weight of an evacuated bombe.
■
KEYPOINTING
■
1) Be sure to charge the refrigerant at around 25
°
C.
2) Be sure to keep -5g in the winter and +5g in summer.
※ Calculation of amount of refrigerant charged (
Wc)
Wc = Wa - Wb
Wa : weight after charging
Wb : weight before charging
( = weight of an evacuated cylinder)
