Carrier X-POWER Series Service Manual page 114

R410a DC Inverter 60Hz Carrier service manual
4) Detection by use of halogen leak detector
Using halogen leak detector when finding out pressure drop but not finding the leak source.
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a. Keep nitrogen at 3.0kgf/cm .
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b. Supplement refrigerant to 5.0kgf/cm .
c. Use halogen leak detector, methane leak detector and electric leak detector for detection.
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d. If the leak source still could not be found, continuously pressurize to 40.0kgf/cm (R410A) and then
detect again.
4. Caution
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1) The air tightness test is conducted by pressurize nitrogen (R410A system: 40kgf/cm ).
2) It is not allowed to adopt oxide, flammable gas and toxic gas to conduct air tightness test.
3) Before pressure-keeping reading, let it rest for several minutes till pressure is stable, to record
temperature, pressure value for future modification.
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4) After pressure-keeping is over, release system pressure to 5~8 kgf/cm and then conduct
pressure-keeping and storage.
5) If pipeline is too long, conduct phase-in detection.
a. Inner side of pipeline
b. Inner side of pipeline + upright
c. Inner side of pipeline + upright+ outer side of pipeline
3.3. Vacuum Drying
3.3.1 Purpose and highlights of vacuum drying
3.3.1.1 Purpose of vacuum drying
1. Dehumidify the system to prevent ice-blockage and copperizing. Ice-blockage shall cause abnormal
operation, while copperizing shall damage compressor.
2. Eliminating the non-condensable gas of system to prevent oxidizing components, system pressure
fluctuation, and bad heat exchanging during the system operation.
3. Detect leak source from reverse rotate.
3.3.1.2 Selection of vacuum pump
1. The limit of vacuum degree is below -756mmHg.
2. The discharge of vacuum pump is over 4L/s.
3. The precision of vacuum pump is over 0. 02mmHg.
Highlights of R410A system:
After the vacuum process of R410A refrigerant circulation is over, vacuum pump stops running and the
lubricant in vacuum pump shall flow back to air conditioning system, for the inner of pump soft pipe is in
vacuum status. In addition, same situation shall happen if vacuum pump suddenly stops during
132 Installation