AUX-DC inverter ARV outdoor unit individual series technical manual
105
Gradual pressurization test
1
st
stage - Large leakage check: 0.3MPa more 3 minutes.
2
nd
stage - Big leakage check: 1.5MPa more than 3 minutes.
3
rd
stage – Small leakage check: 4.3MPa more than 24hours.
Observe pressure drops.
It’s necessary to correct if pressurized temperature is different from observed ambient temperature with
difference of 0.01MPa/1℃.
Correction value =(pressurized temperature - observed temperature)x0.1
Example:
Pressure is 4.3MPa and temperature is 25℃ in case of pressurization.
After 24 hours, if the pressure is 4.25MPa and temperature is 20℃, it is deemed qualified.
Check leakage point.
Ifthere is pressure drop but leakage point can’t be found in pressure test:
1. Discharge nitrogen until the pressure is 0.3MPa.
2. Charge R410a refrigerant to 0.5MPa (namely the mixed state of nitrogen and refrigerant).
3. Check with halogen lamp, butane gas(petroleum gas) detector and electric detector.
4. If leakage point can’t be found, recheck by continuously pressurize up to 2.8MPa. (maximum pressure is
4.3MPa.
3.8 Vacuum Drying
3.8.1 Purpose of vacuum drying
1. Remove moisture from the system to prevent ice-blockage and coppering. Ice-blockage will cause
abnormal operation, while coppering may damage compressor.
2. Eliminating the non-condensable gas of system prevents oxidizing of internal components, system
pressurefluctuation, and low heat exchange performance.
3. Detect leakage source from reverse rotate.
3.8.2 Selection of vacuum pump
1. Vacuuming suction must be less than -14.6PSI(756mmHg).
2. The discharge of vacuum pump is over 4L/s.
3. The precision of vacuum pump is over 0.001ft.H
2
O(0. 02mmHg)
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