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Connection example (For Gas pipe φ 25.4)
Front connection Bottom connection
Table. A Tightening torque
Pipe
Liquid valve
Gas valve
Spindle
8.1 to 9.9 N·m
(83 to 101 kgf·cm)
Blank cap
18.0 to 22.0 N·m
(184 to 224 kgf·cm)
Charging port cap
11.4 to 14.0 N·m
(116 to 143 kgf·cm)
27.0 to 33.0 N·m
(275 to 337 kgf·cm)
22.5 to 27.5 N·m
(229 to 280 kgf·cm)
11.4 to 14.0 N·m
(116 to 143 kgf·cm)
Liquid pipe
(locally purchased)
Gas pipe
(locally purchased)
Joint pipe A
(accessory)
Fig. B
Valve
Open
Blank cap Close
Indoor unit
Liquid pipe
(locally purchased)
Gas pipe
(locally purchased)
5.3.4. Handling precautions for the valves
• Mounted part of Blank cap is sealed for protection.
• Fasten blank cap tightly after opening valves.
Operating the valves
• Use a hexagon wrench.
Liquid valve: size 4 mm, Gas valve: size 8 mm.
Opening:
(1) Insert the hexagon wrench into the valve shaft, and turn it counterclockwise.
(2) Stop turning when the valve shaft can no longer be turned. (Open position)
Closing:
(1) Insert the hexagon wrench into the valve shaft, and turn it clockwise.
(2) Stop turning when the valve shaft can no longer be turned. (Closed position)
Opening direction
Liquid pipe
Opening direction
Hexagon wrench
Seal cap installation portion)
Gas pipe
5.4. Connection system
Fig. A Connection system
Outdoor unit
Pressure gauge
Pressure regulating valve
Vacuum pump
Scale
Charging port cap
Spindle
Open
Close
Nitrogen
Hexagon wrench
5.5. Sealing test
CAUTION
Use only nitrogen gas.
Never use refrigerant gas, oxygen, in fl ammable gas, or poisonous gas to pressurize the system.
(If oxygen is used, there is the danger of an explosion.)
Do not apply shock during sealing test.
It can rupture the pipes and cause serious injury.
Do not turn on the power unless all operations are complete.
Do not block the walls and the ceiling until the sealing test and the charging of the refrigerant gas have been completed.
After connecting the pipes, perform a sealing test.
Recheck that the spindle of the 3-way valve is closed before performing a sealing test.
(Fig. B)
Pour nitrogen gas through both the liquid pipe and the gas pipe.
Pressurize nitrogen gas to 4.2 MPa to perform the sealing test.
Check all fl are connection areas and welded areas.
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.
If a leakage is found, immediately repair it and perform a sealing test again.
* Decrease the pressure of nitrogen gas before blazing.
After completing the sealing test, release the nitrogen gas from both valves.
Release the nitrogen gas slowly.
5.6. Vacuum process
CAUTION
Do not turn on the power unless all operations are complete.
If the system is not evacuated suf fi ciently, its performance will drop.
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.
Use a clean gauge manifold and charging hose that were designed speci fi cally 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.
If moisture might enter the piping, follow below.
(I.e., if doing work during the rainy season, if the actual work takes long enough that condensation may form on the inside of the pipes, if rain might enter the pipes during work, etc.)
• After operating the vacuum pump for two hours, pressurize to 0.05 MPa (i.e., vacuum breakdown) with nitrogen gas, then depressurize down to -100.7kPa (-755mmHg) for an hour using the vacuum pump (vacuum process).
• If the pressure does not reach -100.7kPa (-755mmHg) even after depressurizing for at least two hours, repeat the vacuum breakdown - vacuum process.
After vacuum process, maintain the vacuum for an hour and make sure the pressure does not rise by monitoring with a vacuum gauge.
Evacuation procedure
1) Remove the caps of the gas pipe and liquid pipe and check that the valves are closed.
2) Remove the charging port cap.
3) Connect a vacuum pump and a pressure gauge to a charging hose and connect it to the charging port.
the the pressure gauge becomes -100.7kPa (-755mmHg).
Evacuate from both the gas pipe and the liquid pipe.
5) Continue
-100.7kPa (-755mmHg).
6) Remove
En-7
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