Vaccum Process - Fujitsu AOU48RLXFZ1 Installation Manual

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Vaccum process

• Perform a refrigerant leakage test (air tightness test) to check for leaks using nitrogen gas while all valves in the
outdoor unit are closed. (Use the pressure indicated on the nameplate.)
• Be sure to evacuate the refrigerant system using a vacuum pump.
• The refrigerant pressure may sometimes not rise when a closed valve is opened after the system is evacuated
using a vacuum pump. This is caused by the closure of the refrigerant system of the outdoor unit by the
electronic expansion valve. This will not affect the operation of the unit.
• If the system is not evacuated sufficiently, its performance will drop.
• Use a clean gauge manifold and charging hose that were designed specifically for use with R410A. Using the
same vacuum equipment for different refrigerants may damage the vacuum pump or the unit.
• Do not purge the air with refrigerants, but use a vacuum pump to evacuate the system.
1) Check that the valves are closed by removing the blank caps from the gas and liquid pipes.
2) Remove the charging port cap, and connect the gauge manifold and the vacuum pump to the charging
valve with the service hoses.
3) Vacuum the indoor unit and the connecting pipes until the pressure gauge indicates –0.1 MPa (500microns).
4) When –0.1 MPa (500microns) is reached, make sure it hold vacuum for 60 minutes.
5) Disconnect the service hoses and fit the charging port cap to the charging valve to the specified torque.
(Refer to below table)
6) Remove the blank caps, and fully open the 3-way valves with a hexagon wrench [Torque: 6 to 7 N·m
(4.4 to 5.2 lbf·ft)].
7) Tighten the blank caps of the 3-way valve to the specified torque.
Charging port cap
3-way valve
Blank cap
[mm (in1)]
6.35 (1/4)
9.52 (3/8)
12.70 (1/2)
15.88 (5/8)
19.05 (3/4)
Service hose with valve core
Charging port
Blank cap
Hexagon wrench
Use a 4 mm
(5/32") hexagon
wrench
CAUTION
Tightening torque [N·m (lbf·ft)]
10 to 12 (7.4 to 8.8)
6 to 7 (4.4 to 5.2)
Tightening torque
[N·m (lbf·ft)]
20 to 25 (14.8 to 18.4)
20 to 25 (14.8 to 18.4)
25 to 30 (18.4 to 22.1)
30 to 35 (22.1 to 25.8)
35 to 40 (25.8 to 29.5)
Charging port cap
3-way valve
Connecting pipe
Gauge manifold
Vacuum pump
Service hose
Outdoor unit
Pressure gauge Nitrogen
Branch box
Indoor unit
Pressure regulating valve
Vacuum pump
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