Airtight Test, Evacuation, And Refrigerant Charging; Airtight Test - Mitsubishi Electric CITY MULTI Manual De Instalación

Satisfy the minimum insertion depth in the table below when expanding on-site
piping
Pipe diameter
(mm [in])
5 [7/32] or more, less than 8 [11/32]
8 [11/32] or more, less than 12 [1/2]
12 [1/2] or more, less than 16 [21/32]
16 [21/32] or more, less than 25 [1]
25 [1] or more, less than 35 [1-13/32]
35 [1-13/32] or more, less than 45 [1-25/32]
• After evacuation and refrigerant charging, ensure that the handle is fully
open. If operating with the valve closed, abnormal pressure will be imparted
to the high- or low-pressure side of the refrigerant circuit, giving damage to
the compressor, four-way valve, etc.
• Determine the amount of additional refrigerant charge by using the formula,
and charge refrigerant additionally through the service port after completing
evacuation.
• After completing work, tighten the service port and cap securely so as not to
generate any gas leakage. (Refer to the table on the below for appropriate
tightening torque.)
Appropriate tightening torque:
Outer
diameter of Cap
copper pipe (N·m/kg·cm) (N·m/kg·cm)
(mm [in])
ø9.52 [3/8] 15/150
ø12.7 [1/2] 20/200
ø15.88 [5/8] 25/250
ø19.05 [3/4] 25/250
ø25.4 [1] 25/250
ø28.58 [1-1/8] 25/250
Caution:
• Keep the valve closed until refrigerant charging to the pipes to be
added on-site has been completed. Opening the valve before charging
the refrigerant may cause damage to the unit.
• Do not use a leak detection additive.
[Fig. 10.2.3]
A
B
A Example of closure materials (field-supplied)
B Fill the gap at the site
*When not attaching a low-pressure twinning pipe.
Make sure to seal-off the space around areas where the wires and refrigerant
pipes enter the unit to ensure that small animals, rainwater, or snow cannot
enter the unit through such openings and cause damage to the unit.
Caution:
Make sure to seal-off the openings for the pipe and wire retrieval.
• Small animals, rainwater, or snow entering through the openings may
cause damage to the device.
18
Minimum insertion depth
(mm [in])
6 [1/4]
7 [9/32]
8 [11/32]
10 [13/32]
12 [1/2]
14 [9/16]
Size of
Shaft hexagonal Service port
wrench (N·m/kg·cm)
(mm)
6/60 4
9/90 4
15/150 6 12/120
30/300 8
30/300 8
- - 16/160
10.3. Airtight test, evacuation, and
refrigerant charging

1 Airtight test

Perform with the valve of the outdoor unit closed, and pressurize the
connection piping and the indoor unit from the service port provided on the
valve of the outdoor unit. (Always pressurize from both the high-pressure
pipe and the low-pressure pipe service ports.)
[Fig. 10.3.1]
B
B
C
LO
A
C
D
A Nitrogen gas B To indoor unit
D Lo knob E Hi knob
G Low-pressure pipe H High-pressure pipe
J Service port
Observe the following restrictions when conducting an air tightness test
to prevent negative effects on the refrigerating machine oil. Also, with
nonazeotropic refrigerant (R410A), gas leakage causes the composition to
change and affects performance. Therefore, perform the airtightness test
cautiously.
F
G
H
I
HI
E
J
C System analyzer
F Valve
I Outdoor unit