Pipe Connection; Purging Procedures, Leak Test, And Test Run - Mitsubishi Electric MSZA09NA Installation Manual

3-3. PIPE CONNECTION

• Fasten flare nut with a torque wrench as specified in the table.
• When fastened too tight, flare nut may brake after a long period and cause refrigerant
leakage.
Indoor unit connection
Connect both liquid and gas pipings to indoor unit.
• Apply a thin coat of refrigeration oil (J) on the seat surface of pipe.
• For connection, first align the center, then tighten the first 3 to 4 turns of flare nut.
• Use tightening torque table below as a guideline for indoor unit side union joint section,
and tighten using two wrenches. Excessive tightening damages the flare section.
Outdoor unit connection
Connect pipes to stop valve pipe joint of the outdoor unit in the same manner applied for
indoor unit.
• For tightening, use a torque wrench or spanner and use the same tightening torque ap-
plied for indoor unit.
3-4. 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 (G), apply taping starting from the entry of outdoor unit.
• Stop the end of piping tape (G) with tape (with adhesive agent attached).
• When piping have to be arranged through above ceiling, closet or where the temper-
ature 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
valve will not work in its initial state fresh out of the factory, totally closed with cap on.)
2) Connect gauge manifold valve and vacuum pump to service port of stop valve on the
gas pipe side of the outdoor unit.
*4 to 5 turns
Stop valve cap
(Torque 19.6 to
*Close
29.4 N•m, 200
*Open to 300 kgf▪cm)
Hexagonal wrench
Service port cap
(Torque 13.7 to
17.7 N•m, 140 to
180 kgf•cm)
Precautions when using the control valve When attaching the control valve
Service port
A
Control valve
Open
Close Charge hose
Body
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 pointer gauge manifold valve remains in
the same position. Confirm that pressure gauge shows –0.101 Mpa [Gauge] (–30 in.Hg
[–760 mmHg]).
6) Remove gauge manifold valve quickly from service port of stop valve.
7) After refrigerant pipes are connected and evacuated, fully open all stop valves on both
sides of gas pipe and liquid pipe. Operating without fully opening lowers the perform-
ance and this causes trouble.
8) Refer to 1-3., 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
Compound pressure gauge
–0.101 MPa
(for R410A)
(–30 in.Hg
[–760 mHg])
Pressure gauge
Stop valve (for R410A)
for LIQUID
Gauge manifold valve
(for R410A)
Handle
Low
Handle High
Charge hose
Stop valve for
(for R410A)
GAS
Adapter for pre-
venting the back
Vacuum pump (or the vacuum
flow
pump with the function to
prevent the back flow)
to the service port, valve core may
deform 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.
4-2. TEST RUN
1) Insert power supply plug into the power outlet and/or
turn on the breaker. Check that all LED lamps are not
lit. If they are blinking, check that the horizontal vane
is installed correctly. Refer to operating instructions for
details.
2) Press the E.O. SW. Test run will be performed for 30
minutes. If the left side lamp of the operation indicator
blinks every 0.5 seconds, inspect the indoor/outdoor
unit connecting wire (A) for mis-wiring. After the test run,
emergency COOL mode (75ºF [24ºC] COOL) will start.
3) To stop operation, press the E.O. SW several times until all LED lamps turn off. Refer to
operating instructions for details.
Checking the remote (infrared) signal reception
Press the ON/OFF button on the remote controller and check that an electronic sound is
heard from the indoor unit. Press the ON/OFF button again to turn the air conditioner off.
• Once the compressor stops, the restart preventive device operates so the compressor
will not operate for 3 minutes to protect the air conditioner.
4-3. AUTO RESTART FUNCTION
This product is equipped with an auto restart function. When the power supply is stopped
during operation, such as during blackouts, the function automatically starts operation in
the previous setting once the power supply is resumed. (Refer to the operating instructions
for details.)
Caution:
• After test run or remote signal reception check, turn off the unit with the E.O. SW or
the remote controller before turning off the power supply. Not doing so will cause the
unit to start operation automatically when power supply is resumed.
To the user
• After installing the unit, make sure to explain the user about auto restart function.
• If auto restart function is unnecessary, it can be deactivated. Consult the service rep-
resentative to deactivate the function. Refer to the service manual for details.
4-4. EXPLANATION TO THE USER
• Using the OPERATING INSTRUCTIONS, explain to the user how to use the air condi-
tioner (how to use the remote controller, how to remove the air filters, how to remove or
put the remote controller in the remote controller holder, how to clean, precautions for
operation, etc.)
• Recommend the user to read the OPERATING INSTRUCTIONS carefully.
E.O.
SW
WASH
reset
Emergency operation switch
(E.O. SW)