Mitsubishi Electric MUZG12NA Installation Manual page 15

4-2. GAS CHARGE
Perform gas charge to unit.
1) 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 conditioner for cooling.
Note:
In case of adding refrigerant, comply with the quantity specified for the refrigerating 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
104°F (40°C)) during cold season. But never use naked fire or steam.
4-3. TEST RUN
Be sure to also check the following.
The outdoor unit is not faulty. When the outdoor unit fails, LED outdoor unit control panel blinks.
Both the gas and liquid stop valves are completely open.
• Test runs of the indoor units should be performed individually. See the installation manual coming with the indoor
unit, and make sure all the units operate properly.
• If the test run with all the units is performed at once, possible erroneous connections of the refrigerant pipes and
the indoor/outdoor unit connecting wires cannot be detected. Thus, be sure to perform the test run one by one.
About the restart protective mechanism
Once the compressor stops, the restart preventive device operates so the compressor will not operate for 3
minutes to protect the air conditioner.
Wiring/piping correction function
This unit has a wiring/piping correction function which corrects wiring and piping combination. When there is pos-
sibility of incorrect wiring and piping combination, and confirming the combination is difficult, use this function to
detect and correct the combination by following the procedures below.
Make sure that the following is done.
• Power is supplied to the unit.
• Stop valves are open.
Note:
During detection, the operation of the indoor unit is controlled by the outdoor unit. During detection, the indoor unit automatically stops operation. This is not a mal-
function.
Procedure
Press the piping/wiring correction switch (SW871) 1 minute or more after turning on the power supply.
• Correction completes in 10 to 20 minutes. When the correction is completed, its result is shown
by LED indication. Details are described in the following table.
• To cancel this function during its operation, press the piping/wiring correction switch (SW871)
again.
• When the correction completed without error, do not press the piping/wiring correction switch
(SW871) again.
When the result was "cannot be corrected", press the piping/wiring correction switch (SW871) again
to cancel this function. Then, confirm the wiring and piping combination in a conventional manner
by operating the indoor units one by one.
• The operation is done while the power is supplied. Make sure not to contact parts other than the
switch, including the P.C. board. This may cause electric shock or burn by hot parts and live parts
around the switch. Contacting the live parts may cause P.C. board damage.
• To prevent electronic control P.C. board damage, make sure to perform static elimination before
operating this function.
• This function does not operate when the outside temperature is 32°F (0°C) or below.
4-4. EXPLANATION TO THE USER
• Using the OPERATING INSTRUCTIONS, explain to the user how to use the air conditioner (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.
Model Indoor unit
MXZ-2C A – B
MXZ-3C
A – C
MXZ-5C A – E
Stop valve
Union
Union
Indoor
unit
Union
Stop valve with
Union service port
Refrigerant gas
cylinder
operating valve
Gauge manifold
(for R410A)
valve (for R410A)
Refrigerant gas cylinder for R410A with siphon
Refrigerant (liquid)
Electronic scale for refrigerant charging
SW871
LED indication during detection:
LED1 LED2 LED3
(Red) (Yellow) (Green)
Lighted Lighted Once
Result of piping/wiring correction function
LED1 LED2 LED3
(Red) (Yellow) (Green)
Completed
Lighted Not lighted Lighted (Problem corrected or
normal)
Not completed
Once Once Once
(Detection failed)
Refer to "SAFETY PRE-
CAUTIONS WHEN LED
Other indications
BLINKS" located behind
the service panel.
Liquid
pipe
Outdoor
unit
Gas
pipe
Charge hose
(for R410A)
LED
Result
En-6