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Vacuum Drying and Leakage Checking
7. Vacuum Drying and Leakage Checking
4.1 Purpose of vacuum drying
➢
Eliminating moisture in system to prevent the phenomena of ice-blockage and copper oxidation.
Ice-blockage shall cause abnormal operation of system, while copper oxide shall damage compressor.
➢
Eliminating the non-condensable gas (air) in system to prevent the components oxidizing, pressure
fluctuation and bad heat exchange during the operation of system.
4.2 Selection of vacuum pump
➢
The ultimate vacuum degree of vacuum pump shall be -756mmHg or above.
➢
Precision of vacuum pump shall reach 0.02mmHg or above.
4.3 Operation procedure for vacuum drying
Due to different construction environment, two kinds of vacuum drying ways could be chosen, namely
ordinary vacuum drying and special vacuum drying.
7.3.1 Ordinary vacuum drying
1. When conduct first vacuum drying, connect pressure gauge to the infusing mouth of gas pipe and liquid
pipe, and keep vacuum pump running for 1hour (vacuum degree of vacuum pump shall be reached
-755mmHg).
2
If the vacuum degree of vacuum pump could not reach -755mmHg after 1 hour of drying, it indicates
that there is moisture or leakage in pipeline system and need to go on with drying for half an hour.
3
If the vacuum degree of vacuum pump still could not reach -755mmHg after 1.5 hours of drying, check
whether there is leakage source.
4
Leakage test: After the vacuum degree reaches -755mmHg, stop vacuum drying and keep the pressure
for 1 hour. If the indicator of vacuum gauge does not go up, it is qualified. If going up, it indicates that
there is moisture or leak source.
7.3.2 Special vacuum drying
The special vacuum drying method shall be adopted when:
1.
Finding moisture during flushing refrigerant pipe.
2.
Conducting construction on rainy day, because rain water might penetrated into pipeline.
3.
Construction period is long, and rain water might penetrated into pipeline.
4.
Rain water might penetrate into pipeline during construction.
Procedures of special vacuum drying are as follows:
1.
Vacuum drying for 1 hour.
2.
Vacuum damage, filling nitrogen to reach 0.5Kgf/cm2 .
Because nitrogen is dry gas, vacuum damage could achieve the effect of vacuum drying, but this
method could not achieve drying thoroughly when there is too much moisture. Therefore, special
attention shall be drawn to prevent the entering of water and the formation of condensate water.
3.
Vacuum drying again for half an hour.
If the pressure reached -755mmHg, start to pressure leakage test. If it cannot reached the value,
repeat vacuum damage and vacuum drying again for 1 hour.
4
Leakage test: After the vacuum degree reaches -755mmHg, stop vacuum drying and keep the pressure
for 1 hour. If the indicator of vacuum gauge does not go up, it is qualified. If going up, it indicates that
there is moisture or leak source.
Summary of Contents for KOB30U-18HFN32
Page 1: ...i KAISAI SUPER DC INVERTER SERIES Service Manual 2019 ...
Page 12: ...Indoor Units 11 Service Space 3 Service Space 1000m m 1000mm 1000m m 1000m m ...
Page 15: ...Indoor Units 14 Wiring Diagrams ...
Page 20: ...Indoor Units 19 Air Velocity Distributions Reference Data 30 42K Cooling Heating ...
Page 21: ...Indoor Units 20 Air Velocity Distributions Reference Data 48 55K Cooling Heating ...
Page 26: ...Indoor Units 25 Field Wiring 10 Field Wiring KCD 24HRF32 KCD 36HRF32 ...
Page 27: ...Indoor Units 26 Field Wiring KCD 48HRF32 KCD 55HRF32 ...
Page 49: ...Indoor Units 48 Field Wiring 10 Field Wiring 18k 55k ...
Page 53: ...Indoor Units 52 Service Space 3 Service Space ...
Page 55: ...Indoor Units 54 Wiring Diagrams ...
Page 72: ...Indoor Units 71 Service Space 3 Service Space ...
Page 73: ...Indoor Units 72 Wiring Diagrams 4 Wiring Diagrams KCA3U 12HRF32X ...
Page 82: ...Outdoor Units Outdoor Units 82 10 Field Wiring KCA3U 12HRF32X ...
Page 87: ...Outdoor Units 87 Wiring Diagrams 3 Wiring Diagrams KOB30 12HFN32X ...
Page 88: ...Outdoor Units 88 Wiring Diagrams KOB30U 18HFN32 ...
Page 89: ...Outdoor Units 89 Wiring Diagrams KOCA30U 24HFN32 ...
Page 90: ...Outdoor Units 90 Wiring Diagrams ...
Page 91: ...Outdoor Units 91 Wiring Diagrams KOD30U 36HFN32 ...
Page 92: ...Outdoor Units 92 Wiring Diagrams ...
Page 93: ...Outdoor Units 93 Wiring Diagrams KOE30U 48HFN32 KOE30U 55HFN32 ...
Page 118: ...Installation 119 Refrigerant pipe installation ...
Page 183: ...Controller Electrical Control System 184 ...
Page 184: ...Controller Electrical Control System 185 ...