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Tightening torque for connection of flare pipe
The pressure of R410A is higher than R22. (Approx. 1.6 times.) Therefore securely tighten the flare pipes which connect the outdoor
unit and the indoor unit with the specified tightening torque using a torque wrench.
If any flare pipe is incorrectly connected, it may cause not only a gas leakage but also trouble in the refrigeration cycle.
*1 When connecting a capacity class 16 pipe to the indoor unit, attach the
expander which is available as an optional accessory to the 9.52 mm
diameter packed valve of the outdoor unit.
10-5-3. Evacuating
After the piping has been connected to the indoor unit, perform the air purge.
Use a vacuum pump
Be sure to use a vacuum pump with counter-flow prevention function so that
oil inside the pump does not flow back into the air conditioner pipes when the
pump stops. (If oil inside the vacuum pump enters into the air conditioner
circuit which uses R410A, trouble with the refrigeration system may develop.)
1. Connect the charge hose from the manifold valve to the service port of
the gas side packed valve.
2. Connect the charge hose to the port of the vacuum pump.
3. Open fully the low pressure side handle of the gauge manifold valve.
4. Operate the vacuum pump to begin evacuating. Perform evacuating for
about 15 minutes if the piping length is 20 meters (15 minutes for 20
meters) (assuming a pump capacity of 27 liters per minute). Confirm that
the compound pressure gauge reading is –101 kPa (–76 cmHg).
5. Close the low pressure valve handle of gauge manifold.
6. Open fully the valve stem of the packed valves (both sides of Gas and
Liquid).
7. Remove the charging hose from the service port.
8. Securely tighten the caps on the packed valves.
9. Perform steps 1 through 8 above on each connected indoor unit.
Connectable capacity class
ABTotal
M14 10, 13 10, 13 23
M18 10, 13, 16
*1
10, 13, 16
*1
26
AIR PURGE
Evacuate the air in the connecting pipes and in the indoor unit using a vacuum pump. Do not use the refrigerant in the outdoor unit.
For details, see the vacuum pump manual.
CAUTION
• IMPORTANT POINTS FOR PIPING WORK
(1) Keep dust and moisture from entering the pipes.
(2) Tighten connections carefully (between pipes and unit).
(3) Evacuate the air in the connecting pipes using a VACUUM PUMP.
(4) Check for gas leaks at all connections.
Outdoor unit
Indoor unit
Unit A
Unit B
9.52
6.35
9.52
6.35
Compound pressure gauge
–101 kPa (–76 cmHg)
Handle Lo
Charge hose
(For R410A only)
Pressure gauge
Manifold valve
Handle Hi
(Keep full closed)
Charge hose
(For R410A only)
Connecting pipe
Vacuum pump adapter for
counter-flow prevention
(For R410A only)
Vacuum
pump
Packed valve at liquid side
Packed valve at gas side
Service port
(Valve core (Setting pin))
φ
φ
φ
φ
•