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WT09050X01
9-8. Evacuation of the system
Do not purge the air using refrigerant. Use a vacuum pump to evacuate the system.
- Residual gas in the refrigerant lines will cause bursting of the pipes or an explosion.
Use a vacuum pump with a check valve.
- If the vacuum pump oil flows back into the refrigerant lines, the refrigerant oil may deteriorate
and the compressor may malfunction.
<Evacuation procedures>
① Evacuate the system from both service ports, using a vacuum pump with the service valves closed.
② After the vacuum reaches 650 Pa, continue evacuation for at least one hour.
③ Stop the vacuum pump and leave it for an hour.
④ Verify that the vacuum has not increased by more than 130 Pa.
⑤ If the vacuum has increased by more than 130 Pa, water infiltration is suspected. Pressurize the system with dry
nitrogen gas up to 0.05 MPa. Repeat ① though ⑤ until the vacuum is increased by 130 Pa or below. If the
results persist, then perform the "Triple Evacuation" below.
<Triple Evacuation>
① Evacuate the system to 533 Pa from both service ports, using a vacuum pump.
② Pressurize the system with dry nitrogen gas up to 0 Pa from the discharge service port.
③ Evacuate the system to 200 Pa from the suction service port, using a vacuum pump.
④ Pressurize the system with dry nitrogen gas up to 0 Pa from the discharge service port.
⑤ Evacuate the system from both service ports, using a vacuum pump.
⑥ After the vacuum reaches 66.7 Pa, stop the vacuum pump and leave it for an hour. A vacuum of 66.7 Pa must
be maintained for at least one hour.
⑦ Verify that the vacuum has not increased for at least 30 minutes.
LO
HI
Ⓐ
Ⓑ Ⓒ
Ⓝ
Ⓝ
Ⓔ
Ⓓ
Ⓕ
Ⓞ
Ⓖ
Ⓗ
Ⓘ
Ⓚ
Ⓙ
Ⓛ
Ⓜ
Ⓐ Gauge manifold
Ⓑ Low pressure knob
Ⓒ High pressure knob
Ⓓ Service valve
Ⓔ Low-pressure pipe
Ⓕ High-pressure pipe
Ⓖ Service port
Ⓗ Three-way joint
Ⓘ Valve (vacuum pump)
Ⓙ Valve (for charging refrigerant)
Ⓚ Refrigerant tank
Ⓛ Scale
Ⓜ Vacuum pump
Ⓝ To indoor unit
Ⓞ Outdoor unit
・Use a scale that can measure down to 0.1 kg (0.1 oz).
・Recommended vacuum gauge: ROBINAIR 14830A Thermistor Vacuum Gauge or Micron Gauge
・Do not use a gauge manifold to measure the vacuum pressure.
・Use a vacuum pump capable of attaining a vacuum of 65 Pa (abs) within five minutes of operation.
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