Midea MTB1T-96CWN1 Technical & Service Manual page 64

Midea R410A T3 50Hz Top-discharge Series
After this connection has cooled, remove the nitrogen source from the liquid fitting service
port.

Replace the Schrader core in the liquid and vapor valves.

Leak test all refrigerant piping connections including the service port flare caps to be sure
they are leak tight.

Do not over tighten. (between 40 and 60 inch-lbs. maximum.)

Evacuate the vapor line, evaporator and the liquid line, to 500 microns or less.

Replace cap on service ports. Do not remove the flare caps from the service ports except
when necessary for servicing the system.

Release the refrigerant charge into the system. Open both the liquid and vapor valves by
removing the plunger cap and with a hex wrench back out counter-clockwise until valve
stem just touches the chamfered retaining wall.

Replace plunger cap finger tight, then tighten an additional 1/12 turn (1/ hex flat). Cap must
be replaced to prevent leaks.

Do not connect manifold gauges unless trouble is suspected. Approximately 3/4 ounce of
refrigerant will be lost each time a standard manifold gauge is connected.

Never attempt to repair any brazed connections while the system is under pressure. Personal
injury could result.

After the pipes between the indoor unit and the outdoor unit are connected, replenish
compressed nitrogen to perform airtight test.

The airtight test is performed by using the compressed nitrogen, 2.94MPa (30kg/cm

Tighten the spool of the low pressure valve and high pressure valve before compressing the
nitrogen.

Compress the nitrogen at the air vent of the gas valve.

The gas value and liquid value are closed in the process of compressing the nitrogen.

Do not use oxygen, flammable gas or toxic gas in the airtight test.

Vacuum
From the following table, select a method of expelling air.
Length of connective pipe
63
(Single pass)
Procedure of expelling air
MCAC-UTSM-201707
2
G).