Pipe Connection - Mitsubishi Electric MXZ-2D33VA Installation Manual

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 out-
door 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 refrigerant 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
) 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
) 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 5 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 -0.0 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. Oper-
ating without fully opening lowers the performance and this causes
trouble.
8) Refer to -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.
0) L eak test
4-2. GAS CHARGE
Perform gas charge to unit.
) Connect gas cylinder to the service port of stop valve.
2) Perform air purge of the pipe (or hose) coming from refrigerant gas cylinder.
3) Replenish specified amount of the refrigerant, while operating the air condi-
tioner for cooling.
Note:
In case of adding refrigerant, comply with the quantity specified for the refrigerat-
ing cycle.
CAUTION:
When charging the refrigerant system with additional refrigerant, be sure to use
liquid refrigerant. Adding gas refrigerant may change the composition of the
refrigerant in the system and affect normal operation of the air conditioner. Also,
charge the liquid refrigerant slowly, otherwise the compressor will be locked.
To maintain the high pressure of the gas cylinder, warm the gas cylinder with
warm water (under 40°C) during cold season. But never use naked fire or steam.
Stop valve
*4 to 5 turns for GAS
*Close
*Open
Hexagonal wrench
Service port cap
(Torque 3.7 to 7.7 N•m,
40 to 80 kgf•cm)
Precautions when using
the control valve
Service
port
Control
valve
Open
Close
A
Body
Union
Indoor
unit
Union
Indoor
unit
Refrigerant gas
cylinder
operating valve
(for R40A)
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.
Compound pressure
–0.0 MPa
gauge (for R40A)
(–760 mmHg)
Pressure gauge
Stop valve
(for R40A)
cap (Torque
Gauge manifold
9.6 to 29.4
valve (for R40A)
N•m, 200 to
300 kgf•cm)
Handle High
Handle
Low
Stop valve
Charge hose
for LIQUID
(for R40A)
Vacuum pump
(for R40A)
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.
Charge hose
(for R40A)
Stop valve
Liquid pipe
Gas pipe
Outdoor
unit
Liquid pipe
Gas pipe
Service port
Gauge manifold
valve (for R40A)
Charge hose (for R40A)
Refrigerant gas cylinder
for R40A with siphon
Refrigerant (liquid)
Electronic scale for
refrigerant charging
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