Evacuation Of The System - Mitsubishi Electric City Multi PURY-HP-TNU-A Série Manuel D'installation

Caulk with a nonflammable material such as mortar.
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Nonflammable insulation material
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・When caulking the gaps with mortar, cover the section of the pipe that goes through the wall with a metal sheet to prevent the insulation material
from sagging. For this section, use nonflammable insulation and covering materials. (Vinyl tape should not be used.)

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 (0.0943 psi/5 Torr), 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 (0.01886 psi/1 Torr).
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
(7.25 psi/375 Torr). 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 (0.07729 psi/4 Torr) from both service ports, using a vacuum pump.
② Pressurize the system with dry nitrogen gas up to 0 Pa (0 psi/0 Torr) from the discharge service port.
③ Evacuate the system to 200 Pa (0.029 psi/1.5 Torr) from the suction service port, using a vacuum pump.
④ Pressurize the system with dry nitrogen gas up to 0 Pa (0 psi/0 Torr) 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 (0.09672 psi/5 Torr), 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.
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HI
LO
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・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.
WT09112X02
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GB-24
Gauge manifold
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Low pressure knob
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High pressure knob
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Service valve
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Low-pressure pipe
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High-pressure pipe
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Service port
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Three-way joint
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Valve (vacuum pump)
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Valve (for charging refrigerant)
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Refrigerant tank
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Scale
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Vacuum pump
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To indoor unit
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Outdoor unit
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