McQuay 5CKWS 10CR Installation Manual page 10

Refrigerant piping is important in particular. Refrigeration cycle of the split air conditioner is realized
by the perfect piping work.
Piping Length And Elevation
If the piping is too long, both the capacity and reliability of unit will drop. As the number of bends increase, resistance to
flow of refrigerant system increases, thus lowering cooling capacity and as a result the compressor may become defective.
Always choose the shortest path and follow the recommendation as tabulated below:
MODEL (5CKWS-CR)
Maximum length, m (ft)
Max. elevation, m (ft)
Max. number of bends
Liquid pipe size
Gas pipe size
Piping Connection
• Do not use contaminated or damaged copper tubing. If any piping, evaporator or condenser had been exposed or had been
opened for 15 seconds or more, then vacuum and purge with field supplied refrigerant. Generally, do not remove plastic,
rubber plugs and brass nuts from the valves, fittings, tubing and coils until it is ready to connect suction or liquid line into
valves or fittings.
• If any brazing work is required, ensure that nitrogen gas is passed through coil and joints while the brazing work is being
done. This will eliminate soot formation on the inside wall of copper tubings.
• Cut the pipe stages by stages, advancing the blade of pipe cutter slowly. Extra force and a deep cut will cause more
distortion of pipe and therefore extra burr.
• Remove burrs from cut edges of pipes with a remover. This will avoid unevenness on the flare face which will cause gas
leak.
• Flare the pipe with extra length above the flaring tool as shown in the table below.
Copper tube
Swaging block
• The flared edge must be even and not cracked or scratched.
• Align the center of the piping and sufficiently tighten the flare nut with fingers. Finally, tighten the flare nut with torque
wrench until the wrench clicks.
• Be sure to execute heat insulation. (polyurethane form with thickness more than 15 mm)
• Except the water source heat pump unit which is pre-charge with refrigerant, the fan coil unit and the refrigerant connection
pipes must be purged because the air that contain moisture remaining in the refrigerant cycle may cause malfunction to the
compressor.
REFRIGERANT PIPING WORK
10
12 (39)
5 (16.4)
10
1/4"
3/8"
Pipe Size mm / (in)
6.35 (1/4)
9.53 (3/8)
12.7 (1/2)
15.88 (5/8)
19.05 (3/4)
1-6
15 20
12 (39) 15 (49)
5 (16.4) 8 (26.2)
10 10
1/4" 1/4"
1/2" 1/2"
Ø Tube, D
Inch mm
1/4" 6.35
3/8" 9.52
1/2" 12.70
5/8" 15.88
3/4" 19.05
Torque Nm / (ft - lb)
18 (13.3)
42 (31.0)
55 (40.6)
65 (48.0)
78 (57.6)
A (mm)
Imperial Rigid
1.3 0.7
1.6 1.0
1.9 1.3
2.2 1.7
2.5 2.0