Flaring Work And Pipe Connection; Purging Procedures, Leak Test, And Test Run - Mitsubishi Electric MXZ-4C80VA Manual De Instalación

3. FLARING WORK AND PIPE CONNECTION

3-1. FLARING WORK
1) Cut the copper pipe correctly with pipe cutter. (Fig. 1, 2)
2) Completely remove all burrs from the cut cross section of pipe. (Fig. 3)
• Aim the copper pipe downward while removing burrs to prevent
burrs from dropping in the pipe.
3) Remove flare nuts attached to indoor and outdoor units, then put them
on pipe having completed burr removal. (Not possible to put them on
after flaring work.)
4) Flaring work (Fig. 4, 5). Firmly hold copper pipe in the dimension
shown in the table. Select A mm from the table according to the tool
selected.
5) Check
• Compare the flared work with Fig. 6.
• If flare is noted to be defective, cut off the flared section and do flar-
ing work again.
Pipe diameter Nut
Clutch
(mm) (mm)
type tool
for R410A
ø6.35 (1/4") 17
ø9.52 (3/8") 22
0 to 0.5
ø12.7 (1/2") 26
ø15.88 (5/8") 29
3-2. PIPE CONNECTION
1) Apply a thin coat of refrigeration oil (G) to the flared ends of the pipes
and the pipe connections of the outdoor unit.
2) Align the center of the pipe with that of the pipe connections of the out-
door unit, then hand tighten the flare nut 3 to 4 turns.
3) Tighten the flare nut with a torque wrench as specified in the table.
• Over-tightening may cause damage to the flare nut, resulting in refrig-
erant leakage.
• Be sure to wrap insulation around the piping. Direct contact with the
bare piping may result in burns or frostbite.
3-3. INSULATION AND TAPING
1) Cover piping joints with pipe cover.
2) For outdoor unit side, surely insulate every piping including valves.
3) Using piping tape (E), apply taping starting from the entry of outdoor
unit.
• Stop the end of piping tape (E) with tape (with adhesive agent at-
tached).
• When piping have to be arranged through above ceiling, closet or
where the temperature and humidity are high, wind additional commer-
cially sold insulation to prevent condensation.

4. PURGING PROCEDURES, LEAK TEST, AND TEST RUN

4-1. PURGING PROCEDURES AND LEAK TEST
1) Remove service port cap of stop valve on the side of the outdoor unit
gas pipe. (The stop valves are fully closed and covered in caps in their
initial state.)
2) Connect gauge manifold valve and vacuum pump to service port of
stop valve on the gas pipe side of the outdoor unit.
3) Run the vacuum pump. (Vacuumize for more than 15 minutes.)
4) Check the vacuum with gauge manifold valve, then close gauge mani-
fold valve, and stop the vacuum pump.
5) Leave as it is for one or two minutes. Make sure the pointer of gauge
manifold valve remains in the same position. Confirm that pressure
gauge shows -0.101 MPa [Gauge] (-760 mmHg).
6) Remove gauge manifold valve quickly from service port of stop valve.
7) Fully open all stop valves on the gas pipe and the liquid pipe. Operat-
ing without fully opening lowers the performance and this causes trou-
ble.
8) Refer to 1-2., and charge the prescribed amount of refrigerant if
needed. Be sure to charge slowly with liquid refrigerant. Otherwise,
composition of the refrigerant in the system may be changed and af-
fect performance of the air conditioner.
9) Tighten cap of service port to obtain the initial status.
10) Leak test
En-5
A (mm) Tightening torque
Clutch Wing nut
type tool type tool N•m
for R22 for R22
13.7 to 17.7 140 to 180
1.5 to 2.0
34.3 to 41.2 350 to 420
1.0 to 1.5
49.0 to 56.4 500 to 575
2.0 to 2.5
73.5 to 78.4 750 to 800
Copper pipe
Burr
Spare reamer
Pipe cutter
kgf•cm
Die
Flare nut
WARNING
When installing the unit, securely
connect the refrigerant pipes before
starting the compressor.
CAUTION
When there are the ports which are
not used, make sure their nuts are
tightened securely.
Stop valve cap
*4 to 5 turns
(Torque 19.6 to
29.4 N•m, 200
*Close
to 300 kgf•cm)
*Open
Hexagonal wrench
Service port cap
(Torque 13.7 to
17.7 N•m, 140 to
180 kgf•cm)
Precautions when using
the control valve
A
Control
valve
Open
Service port
Close
Charge hose
Body (for R410A)
No good
Good
Copper
pipe
Tilted Uneven Burred
Fig. 1
Flaring tool
Clutch type Wing nut type
Fig. 3
Inside is shin-
ing without any
Smooth all
scratches.
around
Copper pipe
Even length
all around
Fig. 5
Compound pressure
–0.101MPa
gauge (for R410A)
(–760 mmHg)
Pressure gauge
(for R410A)
Gauge manifold
valve (for R410A)
Stop valve
for GAS
Handle High
Handle
Low
Charge hose
(for R410A)
Vacuum pump
Stop valve (for R410A)
for LIQUID
When attaching the control valve to
the service port, valve core may de-
form or loosen if excess pressure is
applied. This may cause gas leak.
When attaching the control valve to
the service port, make sure that the
valve core is in closed position, and
then tighten part A. Do not tighten
part A or turn the body when valve
core is in open position.
Fig. 2
Fig. 4
Fig. 6