Refrigerant Piping Work - McQuay MCK020A Technical Manual

R R R R R efrig efrig efrig er er ant Piping ant Piping W W W W or ant Piping
efriger efrigerant Piping Work erant Piping
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 the unit will drop. As the number of bends increases,
resistance to flow of refrigerant increases, thus lowering the cooling capacity and as a result overloading the
compressor which may cause the compressor to become defective. Always choose the shortest path and follow the
recommendation as tabulated below.
Indoor MCK 015B/BR
MODEL
MLC 015C/CR
Outdoor
M4LC 015B/BR
Max. length (m) 12
Max. elevation (m) 5
Max. no of bends 10
Liquid pipe size ¼"
Gas pipe size ½"
Indoor
Model
Outdoor
Max. length (m)
Max. elevation (m)
Max. no of bends
Liquid pipe size
Gas pipe size
Remark : The refrigerant pre-charged in the outdoor unit is for piping length up to 7.62m
Piping Connection
Do not use contaminated or damaged copper tubing. If piping for evaporator or condenser are exposed or had been
opened for 15 seconds or more, vacuum and purge with field supplied refrigerant. Generally, do not remove plastic,
rubber plugs and brass nuts from valves, fittings, tubing and coils until it is ready to do the connection for suction and
liquid line.
If any brazing work is required, ensure that nitrogen gas is passed through coil and joints while brazing work is being
carried out. This will eliminate soot formation on the inside wall of copper tubing.
Cut the pipe stage by stage, advance the blade of pipe cutter slowly. Extra force and deep cut will cause more
distortion of pipe and therefore produce 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.
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 outdoor unit which is pre-charged with refrigerant, the indoor 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.
Additional Charge
The refrigerant is pre-charged in the outdoor unit, but additional charge of refrigerant after vacuuming is not
necessary. Follow the recommendation as tabulated below.
ork k k k or or
MCK 020A/AR MCK 025A/AR
MCK 020B/BR MCK 025B/BR
MLC/ M4LC MLC/M4LC
020B/BR 025B/BR
15 15
8 8
10 10
¼" 3/8"
5/8" 5/8"
MCK 010C/CR MCK 015C/CR
MLC 010C/CR MLC 015C/CR
M4LC 010B/BR M4LC 015B/BR
12 12
5 5
10 10
¼" ¼"
3/8" 3/8"
124
MCK 030A/AR MCK 040A/AR
MLC MLC/M4LC MLC
030B/BR 030C/CR 035C/CR
15 45 45
8 25 25
10 10 10
3/8" 3/8" 3/8"
5/8" 5/8" ¾"
MCK 020C/CR
MLC/M4LC 020B/BR
15
8
10
¼"
5/8"
MCK 050A/AR
MLC/M4LC MLC/M4LC
040C/CR 050C/CR
45 45
25 25
10 10
3/8" 3/8"
¾" ¾"