Midea M2OC-18HFN1-M - Installation Procedures; Wrench Torque Specifications; Cable Connection Guidelines; Piping Length and Elevation Limits

6. Installation Details
6.1 Wrench torque sheet for installation
Outside diameter
Torque
Additional tightening torque
mm
inch
N.cm
N.cm
Ф6.35
1/4
1500(153kgf.cm)
1600(163kgf.cm)
Ф9.52
3/8
2500(255kgf.cm)
2600(265kgf.cm)
Ф12.7
1/2
3500(357kgf.cm)
3600(367kgf.cm)
6.2 Connecting the cables
The power cord connection should be
selected according to the following
specifications sheet.
Unit
AWG
Dual-zone(18K outdoor unit)
14
Tri-zone (27K/30K outdoor unit).
14
Quad-zone(36K outdoor unit)
12
For indoor unit and outdoor unit connection
line, 16AWG is ok for all.
6.3 Pipe length and the elevation
Maximum piping length and height difference
1 drive 2
1 drive 3
1 drive 4
Max. length for all rooms
(m)
30(98ft)
45(150ft)
60(200ft)
Max. length for one IU (m)
20(65.6ft)
25(82ft)
30(98ft)
Max. height
difference
between IU
and OU (m)
OU
higher
than IU
10(33ft)
10(33ft)
10(33ft)
OU lower
than IU
15(49.2ft)
15(49.2ft)
15(49.2ft)
Max. height difference
between IUs (m)
10(33ft)
10(33ft)
10(33ft)
Additional refrigerant charge
1 drive 2
1 drive 3
1 drive 4
Chargeless pipe
length (m)
15(49.2ft)
22.5(73.8ft)
30(98.4ft)
Additional
refrigerant
charge
g
15 x (length
for all rooms -
15)
15 x (length
for all rooms –
22.5)
15 x (length
for all rooms -
30)
oz
(.0.161
x(length for all
rooms –
49.2))
(.0.161
x(length for all
rooms –
73.8))
(.0.161x(lengt
h for all rooms
– 98.4))
Caution:
● Refrigerant pipe diameter is different
according to indoor unit to be connected.
When using the extension pipe, refer to the
tables below.
● When refrigerant pipe diameter is different
from that of outdoor unit union (for 18K indoor
unit), additional transfer connector needs to
be used on outdoor unit union.
Indoor unit
Extension pipe diameter
(mm/inch)
Model
Pipe diameter
(mm/inch)
9K
Liquid
6.35(1/4)
Liquid
6.35(1/4)
Gas
9.52(3/8)
Gas
9.52(3/8)
12K 18K
Liquid
6.35(1/4)
Liquid
6.35(1/4)
Gas
12.7(1/2)
Gas
12.7(1/2)
Outdoor unit union diameter (mm/inch)
Indoor unit A/B/C/D
Liquid
6.35(1/4)
Gas
9.52(3/8)
6.4 Installation for the first time
Air and moisture in the refrigerant system have
undesirable effects as below:
● Pressure in the system rises.
● Operating current rises.
● Cooling or heating efficiency drops.
● Moisture in the refrigerant circuit may freeze
and block capillary tubing.
● Water may lead to corrosion of parts in the
refrigerant system.
Therefore, the indoor units and the pipes
between indoor and outdoor units must be leak
tested and evacuated to remove gas and
moisture from the system.
Gas leak check (Soap water method):
Apply soap water or a liquid neutral
detergent on the indoor unit connections or
outdoor unit connections by a soft brush to check
for leakage of the connecting points of the piping.
If bubbles come out, the pipes have leakage.
1. Air purging with vacuum pump