Midea MEHSU-09CHD2 Service Manual page 68

Flare dimension A
Pipe
(mm/in)
diamete
r Min Max
1/4"
8.3/0.33 8.7/0.34
(6.35)
3/8" 12.0/0.4
12.4/0.49
(9.52) 7
1/2" 15.4/0.6
15.8/0.62
(12.7) 1
5/8" 18.6/0.7
19.1/0.75
(15.9) 3
3/4" 22.9/0.9
23.3/0.92
(19) 0

After flared the pipe, the opening part must
be seal by end cover or adhesive tape to
avoid duct or exogenous impurity come into
the pipe.
7. Drill holes if the pipes need to pass the
wall.
8. According to the field condition to bend the
pipes so that it can pass the wall smoothly.
9. Bind and wrap the wire together with the
insulated pipe if necessary.
10. Set the wall conduit
11. Set the supporter for the pipe.
12. Locate the pipe and fix it by supporter

For horizontal refrigerant pipe, the distance
between supporters should not be exceed
1m.

For vertical refrigerant pipe, the distance
between supporters should not be exceed
1.5m.
13. Connect the pipe to indoor unit and outdoor
unit by using two spanners.

Be sure to use two spanners and proper
torque to fasten the nut, too large torque
will damage the flare, and too small torque
may cause leakage. Refer the following
table for different pipe connection.

Torque
Pipe
Diameter
(kgf.cm)
1/4" (6.35) 144~176
3/8" (9.52) 333~407
1/2" (12.7) 504~616
5/8" (15.9) 630~770
Flare shape
90 ° 4 - +
A
Sketch map
(N.cm)
1420~1720
3270~3990
4950~6030
6180~7540
3/4" (19)
12.4.3 First-Time Installation
Air and moisture in the refrigerant system
cause the following problems:
● Increases in system pressure
● Increases in operating current
● Decreases in cooling and heating efficiency
R0.4~0.8
● Blocks in capillary tubing caused by
moisture in the refrigerant circuit freezing
● Corrosion of parts in the refrigerant system
caused by water
The indoor units and the pipes between
indoor and outdoor units must be tested for
leakages and evacuated to remove gas and
moisture from the system.
Gas leak check with soap water:
Apply soap water or a liquid neutral
detergent on the connections with a soft brush
to check for leakage in the pipe connecting
points. If bubbles emerge, the pipes are
leaking.
1. Air Purging Using the Vacuum Pump
1) Completely tighten the flare nuts on the
indoor and outdoor units. Confirm that both
the2-way and 3-way valves are set to the
closed position.
2) Connect the charge hose with the push pin
of the Handle Lo to the 3-way valve gas
service port.
3) Connect the charge hose of the Handle Hi
to the vacuum pump.
4) Fully open the Handle Lo of the manifold
valve.
66
990~1210 9270~11860