McQuay MCC 010C/CR, Manual, Page: 56 / 78

55
Operation Operation
Maximum Pipe Length And Maximum Number Of Bends
•
When the pipe length becomes too long, both the capacity and reliability drop. As the number of bends
increases, system piping resistance to the refrigerant flow increases, thus lowering the cooling capacity,
and as the result the
compressor may become defective. Always choose the shortest path and follow the
recommendation as tabulated below:
MODEL
DATA
010 015 020 025 030 040 050 *060
Max. Length, L 12 m 12 m 15 m 15 m 35 m 35 m 35 m 35 m
Max. Elevation, H 5 m 5 m 8 m 8 m 15 m 15 m 15 m 20 m
Max. No. of bends 10 10 10 10 10 10 10 10
* For cooling unit, need to add external accumulator (Recommended 6kg accumulator)
Piping Sizes (Flare Connection Type)
•
Piping sizes are as follows:
MODEL 010 015 020 025
Liquid (mm/in) 6.35 (1/4) 6.35 (1/4) 6.35 (1/4) 9.52 (3/8)
Suction (mm/in) 9.52 (3/8) 12.70 (1/2) 15.88 (5/8) 15.88 (5/8)
MODEL 030 040 050 060
Liquid (mm/in) 9.52 (3/8) 9.52 (3/8) 9.52 (3/8) 12.70 (1/2)
Suction (mm/in) 15.88 (5/8) 19.05 (3/4) 19.05 (3/4) 19.05 (3/4)
Piping Connection To The Units
•
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.
•
When tightening the flare nut with torque wrench, ensure the direction for tightening follows the arrow on the wrench.
PIPE SIZE (mm/in) TORQUE (Nm)
6.35 (1/4) 18
9.53 (3/8) 42
12.70 (1/2) 55
15.88 (5/8) 65
19.05 (3/4) 78