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Fig. 5-1 Connection system
Indoor
unit
Indoor
unit
R410A
Nitrogen
Indoor
unit
Indoor
unit
R410A
Nitrogen
A) In case of connected one out door unit
Pressure gauge
Pressure regulating valve
Vaccum
pump
Scale
Pressure gauge
Pressure regulating valve
Vaccum
pump
Scale
B) In case of connected many outdoor units
Outdoor unit
Outdoor unit
Outdoor unit
Fig. 5-2
Hexagon
wrench
Spindle
Open
Close
Valve
Open
Close
Cap
CAUTION
• Do not apply shock during sealing test.
It can rupture the pipes and cause serious injury.
• Do not block the walls and the ceiling until the sealing test and the charging of the refrigerant gas have been
completed.
Table 5-1
Charging cap
Pipe
Liquid
valve
Gas
valve
Oil
valve
Spindle
—
27.0 to 30.0 N·m
(270 to 300 kgf·cm)
—
Cap
28.0 to 32.0 N·m
(280 to 320 kgf·cm)
60.0 to 65.0 N·m
(600 to 650 kgf·cm)
20.0 to 25.0 N·m
(200 to 250 kgf·cm)
Charging cap
12.5 to 16.0 N·m
(125 to 160 kgf·cm)
12.5 to 16.0 N·m
(125 to 160 kgf·cm)
12.5 to 16.0 N·m
(125 to 160 kgf·cm)
5. CHARGING WITH REFRIGERANT
5.1. SEALING TEST
After connecting the pipes, perform an sealing test.
Pressurize nitrogen gas to 4.15 MPa to perform the sealing test.
Recheck that the spindle of the 3-way valve are closed before performing a sealing test. (Fig. 5-2)
Pour nitrogen gas through both the liquid pipe and the gas pipe.
* When connecting multiple units, pour nitrogen through 3 locations: liquid pipe, gas pipe, and oil pipe.
Check all flare connections and welds.
Then, check that the pressure has not decreased.
Compare the pressures after pressurizing and letting it stand for 24 hours, and check that the pressure has not decreased.
* When the outdoor temperature changes 5 °C, the test pressure changes 0.05 MPa.
If the pressure has dropped, the pipe joints may be leaking.
Find and repair the area that is leaking.
If a leakage is found, immediately repair it and perform a sealing test again.
After completing the sealing test, release the nitrogen gas from both valves.
Release the nitrogen gas slowly.
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