Triple Evacuation Method - Hitachi UTOPIA R32 Series Installation And Operation Manual

9.2 Triple Evacuation Method

According to the following [Step 1] [Step 2] [Step 3] in order, conduct vacuum drying work.
Step 1
1 Vacuum until the pressure reaches 2000 microns (2.0 mmHg).
2 Pressurize with nitrogen up to 0.3 MPaG (50 PSIG) for 15 minutes.
3 Release pressure until reaching the atmosphere level, as low as 0.03 MPaG (5 PSIG).
Step 2
1 Vacuum until the pressure reaches 1000 microns (1.0 mmHg).
2 Pressurize with nitrogen up to 0.3 MPaG (50 PSIG) for 15 minutes.
3 Release pressure until reaching the atmosphere level, as low as 0.03 MPaG (5 PSIG).
Step 3
1 Vacuum until the pressure reaches 500 microns (0.5 mmHg).
2 Stop vacuum pump.
3 Check that the vacuum 500 microns (0.5 mmHG) can maintain for one hour.

NOTE
• If tool or measuring instruments come into contact with the refrigerant, use the tools or the
measuring instruments exclusively designed for the task at hand.
• Do not perform vacuuming pumping work with valves of the outdoor units open. Otherwise, the
refrigerant charged before shipment may leak and it may result in failure. If moisture remains
inside the pipes, the compressor may be damaged.
PMEN0654 rev.0 - 12/2023
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