Flaring Work And Pipe Connection; Purging Procedures, Leak Test, And Test Run - Mitsubishi Electric MXZ-3B24NA 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 sec-
tion and do flaring work again.
Pipe diameter Nut
[mm (inch)] (mm)
ø6.35 (1/4) 17
ø9.52 (3/8) 22
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 outdoor
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 refriger-
ant 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 attached).
• When piping have to be arranged through above ceiling, closet or where
the temperature and humidity are high, wind additional commercially 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 manifold
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] (
–
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. Operating
without fully opening lowers the performance and this causes trouble.
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 affect performance of
the air conditioner.
9) Tighten cap of service port to obtain the initial status.
10) Leak test
En-5
Clutch type
A [mm (inch)]
Clutch type tool for R410A Clutch type tool for R22
0 to 0.5 1.0 to 1.5
(0 to 0.02) (0.04 to 0.06)
760 mmHg) ( 30 in. Hg).
– –
Good
Copper
pipe
Tilted Uneven Burred
Fig. 1
Flaring tool
Die
Wing nut type
Flare nut
Fig. 4
Wing nut type tool for R22
1.5 to 2.0
(0.06 to 0.08)
2.0 to 2.5
(0.08 to 1.0)
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.
*4 to 5 turns
Stop valve cap
(Torque 19.6 to 29.4 N•m,
*Close
200 to 300 kgf•cm, 15 to
22 ft•lb)
*Open
Hexagonal wrench
Service port cap
(Torque 13.7 to
17.7 N•m, 140 to
180 kgf•cm, 10 to
13 ft•lb)
Precautions when using
the control valve
A
Control
valve
Open
Service port
Close
Charge hose
Body (for R410A)
No good
Copper pipe
Burr
Spare reamer
Pipe cutter
Fig. 2
Smooth all
around
Copper pipe
Fig. 5
Tightening torque
N•m kgf•cm
13.7 to 17.7 140 to 180
34.3 to 41.2 350 to 420
49.0 to 56.4 500 to 575
73.5 to 78.4 750 to 800
–0.101MPa
Compound pressure
[–760 mmHg
gauge (for R410A)
(–30 in. Hg)]
Pressure gauge
(for R410A)
Stop valve
for GAS
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. 3
Inside is shin-
ing without any
scratches.
Even length
all around
Fig. 6
ft•Ib
10 to 13
25 to 30
36 to 42
54 to 58
Gauge manifold
valve (for R410A)
Handle High