17
English
Refrigerant Piping Work
Refrigerant piping
3.
CAUTION
Use the
fl
are nut
fi
xed to the main unit. (To prevent cracking of the
fl
are nut by aged deterioration.)
•
To prevent gas leakage, apply refrigeration oil only to the inner surface of the
fl
are. (Use refrigeration oil for R410A.)
•
Use torque wrenches when tightening the
fl
are nuts to prevent damage to the
fl
are nuts and gas leakage.
•
Align the centres of both
fl
ares and tighten the
fl
are nuts 3 or 4 turns by hand. Then tighten them fully with the torque
wrenches.
Do not apply refrigeration oil
to the outer surface.
Flare nut
Apply refrigeration
oil to the inner
surface of the flare.
Do not apply refrigeration
oil to the flare nut avoid
tightening with over torque.
[Apply oil]
Torque wrench
Piping union
Flare nut
Spanner
[Tighten]
Flare nut tightening torque
Gas side
Liquid side
3/8 inch
1/2 inch
1/4 inch
32.7-39.9N
z
m
49.5-60.3N
z
m
14.2-17.2N
z
m
(330-407kgf
z
cm) (505-615kgf
z
cm)
(144-175kgf
z
cm)
Caution on piping handling
All pipe bends should be as gentle as possible. Use a pipe bender for bending.
•
Selection of copper and heat insulation materials
When using commercial copper pipes and
fi
ttings, observe the following:
•
Insulation material: Polyethylene foam
1)
Heat transfer rate: 0.041 to 0.052W/mK (0.035 to 0.045kcal/mh°C)
Refrigerant gas pipe’s surface temperature reaches 110°C max.
Choose heat insulation materials that will withstand this temperature.
Liquid pipe
Gas pipe
Gas pipe
insulation
Liquid pipe
insulation
Finising tape
Inter-unit
wire
Be sure to insulate both the gas and liquid piping and to provide insulation dimensions as below.
2)
Gas side
Liquid side
Gas pipe thermal insulation
Liquid pipe
thermal insulation
25/35 class
50 class
O.D. 6.4mm
25/35 class
50 class
I.D. 8-10mm
O.D. 9.5mm
O.D. 12.7mm
I.D. 12-15mm
I.D. 14-16mm
Minimum bend radius
Thickness 10mm Min.
30mm or more
40mm or more
30mm or more
Thickness 0.8mm (C1220T-O)
Use separate thermal insulation pipes for gas and liquid refrigerant pipes.
3)
01_EN_3P276870-1.indb 17
01_EN_3P276870-1.indb 17
2/23/2011 5:04:23 PM
2/23/2011 5:04:23 PM
