8
A
B
C
D
5-7
LOWERING THE OPERATING NOISE OF THE OUTDOOR UNIT
• Description of the function:
With this function, you can lower the operating noise of the
outdoor unit when the operation load is small, for example,
during nighttime in COOL mode. However, please note that
the cooling and heating capacity can also be lowered if this
function is activated.
* Initial setting is required to activate this function. Please ex-
plain about this function to your customers and ask them
whether they want to use it.
[How to lower the operating noise]
1
Be sure to turn off the main power for the air conditioner
before making the setting.
2
Set the 3rd Dip Switch of SW1 on the outdoor controller board
to ON to enable this function.
3
Turn on the main power for the air conditioner.
5-8
CHECKING AFTER INSTALLATION
After finishing the installation, check the following items again by marking .
Have special circuits been provided?
Is power supply voltage as specified?
Has indoor/outdoor connecting wire been inserted into terminal block?
Has indoor/outdoor connecting wire been secured firmly?
Has intermediary connection between power cable and indoor/outdoor connecting wire been carried out?
Is combination of connection pipes and indoor/outdoor connecting wire correct (Room A, Room B, Room C,
Room D)?
Is earth cable connection correct?
Has leak test been carried out?
Has air purge been carried out?
Is stop valve fully open?
Has drain discharge been checked?
Is insulation over connection pipe joints correct?
Is strength of installation location well enough?
Have all of
WARNING and
CAUTION items in “1. THE FOLLOWING SHOULD ALWAYS BE OB-
SERVED FOR SAFETY” been checked?
5-9
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.
Indoor
unit
Union
Stop valve
Outdoor
unit
Union
Gauge manifold
valve (for R410A)
Charge hose (for R410A)
Refrigerant gas
cylinder
operating valve
(for R410A)
Refrigerant gas cylinder
for R410A with siphon
Refrigerant (liquid)
Electronic scale for
refrigerant charging
Liquid pipe
Gas pipe
Union
Stop valve with
service port
Union
(MXZ-4A71VA)
CAUTION:
When charging the refrigerant system with additional refrigerant, be sure to use liquid refrigerant. Add-
ing gas refrigerant may change the composition of the refrigerant in the system and affect normal
operation of the air conditioner. Also, charge the system 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.
5-10 TEST RUN
• Be sure to perform the test run for each unit. Make sure each indoor unit operates properly following the
installation manual attached to the unit.
• If you perform the test run for all indoor units at once, you cannot detect any erroneous connection, if any, of
the refrigerant pipes and the indoor/outdoor unit connecting wires.
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.
5-11 EXPLANATION TO THE CUSTOMER
• Recommend the customer to read the OPERATING INSTRUCTIONS carefully.
• Using the OPERATING INSTRUCTIONS for each unit, explain the following to the customer, how to control
temperature, 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.
If the customer (user) is absent, explain to the purchaser (owner, building’s controller, etc) about those
points.
Lower the operating
noise
ON
ON
