Ingersoll-Rand Thermo King CRR DF MPC2000, Maintenance Manual

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Refrigeration Maintenance and Service Operations
114
Refrigerant Charge Inspection
The refrigerant charge should be checked during pretrip and routine maintenance inspections. A low
charge of refrigerant will cause the container temperature to rise due to the lack of liquid refrigerant at the
expansion valve even though the unit is operating in a cooling mode. If the unit is low on R-134a charge,
inspect the unit for refrigerant leaks with a reliable leak detector.
• R-134a Refrigeration System Charge: 3.5 Kg (7.7 lb)
• R-23 Refrigeration System Charge: 3.2 Kg (7.05 lb)
NOTE: See “Receiver Tank Sight Glass” under Unit Instruments in the Operating Instructions
chapter for information about checking the moisture indicator in the sight glass.
Checking the R-134a Refrigerant Charge
1. Inspect the receiver tank sight glass with the unit operating in COOL. If the balls FLOAT in the
receiver tank sight glass, the R-134a charge level is correct.
2. If the balls are NOT FLOATING in the sight glass, the unit MAY be low on R-134a charge. Operate
the unit on COOL for 5 minutes. If the balls float in the receiver tank sight glass, the R-134a charge
level is correct.
3. If the balls do NOT FLOAT in the receiver tank sight glass after operating the unit on COOL for 5
minutes, the unit is low on R-134a charge. With the unit operating on COOL, add liquid R-134a until
the balls FLOAT in the sight glass.
CAUTION: When adding R-134a to the unit, STOP adding refrigerant when the balls float
near the TOP of the sight glass. Continuing to add refrigerant after the balls float at the top of
the sight glass will OVERCHARGE the unit. If necessary, recover refrigerant until the balls no
longer float at the top of the sight glass.
1. Refrigerant charge is OK if the ball floats at any time:
• If the ball does NOT float, the R-134a refrigeration system is
unit is low on refrigerant
Figure 37: R-134a Refrigeration System Receiver Tank