Mitsubishi Electric MXZ-2A20NA-1 Service Manual page 5

2.Refrigerant piping
1 Specifications
Use the copper or copper-alloy seamless pipes for refrigerant that meet the following specifications.
Outside diameter
(inch)
1/4
3/8
1/2
5/8
2 Flaring work and flare nut
Flaring work for R410A pipe differs from that for R22 pipe.
For details of flaring work, refer to Installation manual "FLARING WORK".
Pipe diameter
(inch)
1/4
3/8
1/2
5/8
3.Refrigeration oil
Apply the special refrigeration oil (accessories: packed with indoor unit) to the flare and the union seat surfaces.
4.Air purge
• Do not discharge the refrigerant into the atmosphere.
Take care not to discharge refrigerant into the atmosphere during installation, reinstallation, or repairs to the refrigerant
circuit.
• Use the vacuum pump for air purging for the purpose of environmental protection.
5.Additional charge
For additional charging, charge the refrigerant from liquid phase of the gas cylinder.
If the refrigerant is charged from the gas phase, composition change may occur in the refrigerant inside the cylinder and the
outdoor unit. In this case, ability of the refrigeration cycle decreases or normal operation can be impossible. However,
charging the liquid refrigerant all at once may cause the compressor to be locked. Thus, charge the refrigerant slowly.
Refrigerant gas
cylinder
operating valve
Wall thickness
(inch)
0.0315
0.0315
0.0315
0.0394
Union
Indoor unit
Charge hose (for R410A)
Refrigerant gas cylinder
for R410A with siphon
Refrigerant (liquid)
Electronic scale for refrigerant charging
Insulation material
Heat resisting foam plastic
Specific gravity 0.045 Thickness 0.315 inch
Dimension of flare nut
(inch) [inch]
R410A
17 [11/16]
22 [7/8]
26 [1-1/32]
29 [1-5/32]
Stop valve
Liquid pipe
Gas pipe
Service port
Gauge manifold
valve (for R410A)
5
R22
17 [11/16]
22 [7/8]
24 [15/16]
27 [1-1/16]
Outdoor unit