6 REFRIGERANT PIPING
Tightening connection
Align the centers of the connecting pipes and tighten the flare nut as far as possible with your fingers. Then tighten the nut with a spanner and torque wrench as shown in the figure.
CAUTION
•Do not apply excess torque. Otherwise, the nut may crack depending on the conditions.
| (Unit : N•m) |
|
|
Outer diam. of copper pipe | Tightening torque |
|
|
6.35 mm (diam.) | 14 to 18 (1.4 to 1.8 kgf•m) |
|
|
9.52 mm (diam.) | 33 to 42 (3.3 to 4.2 kgf•m) |
|
|
12.7 mm (diam.) | 50 to 62 (5.0 to 6.2 kgf•m) |
|
|
15.9 mm (diam.) | 63 to 77 (6.3 to 7.7 kgf•m) |
|
|
•Tightening torque of flare pipe connections
Pressure of R410A becomes higher than that of R22. (Approx. 1.6 times) Therefore, using a torque wrench, tighten firmly the flare pipe connecting sections which connect the indoor and outdoor units up to the specified tightening torque.
Incorrect connections may cause not only a gas leakage, but also a trouble of the refrigeration cycle or compressor damage.
Flare at
indoor unit side
| Flare at |
| outdoor unit side |
Half union | Flare nut |
Externally | Internally |
threaded side | threaded side |
Use a wrench to secure. | Use a torque wrench to tighten. |
7 EVACUATING
AIR PURGE
Evacuate the air in the connecting pipes and in the indoor unit using vacuum pump.
Do not use the refrigerant in the outdoor unit. For details, see the manual of vacuum pump.
Use a vacuum pump
Be sure to use a vacuum pump with
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 vacuum pump.
3.Open fully the low pressure side handle of the gauge manifold valve.
4.Operate the vacuum pump to start for evacuating.
Perform evacuating for about 35 minutes if the piping length is total 30 meters for model SM560 and 50 meters for model SM800.
(assuming a pump capacity of 27 liters per minute.) Then confirm that the compound pressure gauge reading is
5.Close the low pressure side 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.
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