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7.6.2 Procedures to enable automatic address setting on indoor
units
Check that the rotary switch IU AD on the indoor unit PC board is set to "00".If it is not set
to "00", it means the address of that device is not set. (Factory default is "00").
Turn on the power of the indoor and outdoor units.
• When the system is normal, nothing will be displayed on the 7-segment display.
• When ERROR is displayed, inspect the units.
Use the "MODE/EXIT", "SELECT", and "ENTER" buttons on the outdoor unit PC board to
configure settings according to the procedures below.
First 2 digits Last 2 digits
(The display when the main power is turned on)
Set to Function mode [F3].
(When [F4] to [F9] are displayed, continue to press
the "SELECT" button until [F3] is displayed.)
Press the "SELECT" button until "11" is displayed.
Press the "ENTER" button for more than 3 seconds.
The number of indoor units with normal settings will be
displayed at the first 2 digits of the 7-segment LED display.
The number of indoor units with error will be displayed at
the last 2 digits.
NOTE:
After the "ENTER" button is pressed, the end processing
will occur for about 30 seconds. During this period, the
7-segment will blink.
End
7.7. Resistance measurement of transmission cable
(Measure with breaker OFF)
CAUTION
Do not turn on the power if the resistance
between the terminals of the transmission
cable is abnormal. Otherwise, the PC
board may be damaged.
Measure the resistance between 2 termi-
nals of a transmission cable.
(1) Transmission cable connecting
indoor units, outdoor units, and
signal amplifiers
Measure the resistance of the signal
amplifier terminal and the terminal of
the indoor and outdoor units con-
nected farthest away from the device
where terminal resistor is measured.
A value from the table is displayed,
depending on the distance from the
signal amplifier and the device where
the terminal resistor is set.
This value is an estimate.
(2) Transmission cable connecting out-
door units in a refrigerant system
The resistance between the terminals
of the transmission cable is 45-60 Ω.
This value is an estimate.
1: Function setting
Automatic address setting for
indoor units
Distance from termination resistor
(m)
0~100
~200
~300
~400
~500
A short circuit somewhere or 2
0 ~
or more termination resistors are
50
connected
50
60
70
80
90
100
110
120
130
140
150
160
170
180
190
Faulty contact or wiring length over
~
500 m
1K
Faulty contact, open circuit, or no
~∞
termination resistor
8. PIPE INSTALLATION II
Fig. A Connection system
Pressure
gauge
Outdoor unit
Indoor
Indoor
Vacuum
unit
unit
pump
Table. A
Pipe
3-way valve
7.0 to 9.0 N·m
Liquid valve
(70 to 90 kgf·cm)
11.0 to 13.0 N·m
Gas valve
(110 to 130 kgf·cm)
8.1. Sealing test
Use only nitrogen gas.
Never use refrigerant gas, oxygen, in flammable gas or poisonous gas to pressurize the
system. (If oxygen is used, there is the danger of an explosion.)
Do not apply shock during sealing test.
It can rupture the pipes and cause serious injury.
Do not turn on the power unless all operations are complete.
Do not block the walls and the ceiling until the sealing test and the charging of the
refrigerant gas have been completed.
After connecting the pipes, perform a sealing test.
Recheck that the 3-way valve are closed before performing a sealing test.
(Fig. B)
Pour nitrogen gas through both the liquid pipe and the gas pipe.
Pressurize nitrogen gas to 4.2 MPa to perform the sealing test.
Check all flare connection areas and brazed areas.
Then, check that the pressure has not decreased.
Compare the pressures after pressurizing and letting it stand for 24 hours, and check that
the pressure has not decreased.
* When the outdoor temperature changes 5°C, the test pressure changes 0.05 MPa.
If the pressure has dropped, the pipe joints may be leaking.
If a leakage is found, immediately repair it and perform a sealing test again.
* Decrease the pressure of nitrogen gas before blazing
After completing the sealing test, release the nitrogen gas from both valves.
Release the nitrogen gas slowly.
8.2. Vacuum process
Do not turn on the power unless all operations are complete.
If the system is not evacuated sufficiently, its performance will drop.
Be sure to evacuate the refrigerant system using a vacuum pump.
The refrigerant pressure may sometimes not rise when a closed valve is opened after
the system is evacuated using a vacuum pump. This is caused by the closure of the
refrigerant system of the outdoor unit by the electronic expansion valve. This will not
affect the operation of the unit.
Use a clean gauge manifold and charging hose that were designed specifically for use
with R410A. Using the same vacuum equipment for different refrigerants may damage
the vacuum pump or the unit.
Do not purge the air with refrigerants, but use a vacuum pump to evacuate the system.
• If moisture might enter the piping, follow below. (i.e., if doing work during the rainy
season, if the actual work takes long enough that condensation may form on the
inside of the pipes, if rain might enter the pipes during work, etc.)
• After operating the vacuum pump for 2 hours, pressurize to 0.05 MPa (i.e., vacuum
breakdown) with nitrogen gas, then depressurize down to -100.7 kPa (-755 mmHg) for
an hour using the vacuum pump (vacuum process).
• If the pressure does not reach -100.7 kPa (-755 mmHg) even after depressurizing for
at least 2 hours, repeat the vacuum breakdown - vacuum process.
After vacuum process, maintain the vacuum for an hour and make sure the pressure
does not rise by monitoring with a vacuum gauge.
Fig. B
Service hose
Pressure regu-
with valve core
lating valve
Charging
Charging
port
port cap
Nitrogen
Blank cap
Connecting
pipe
Scale
Hexagon wrench
4 mm (5/32")
Blank cap
Charging port cap
20.0 to 25.0 N·m
12.5 to 16.0 N·m
(200 to 250 kgf·cm)
(125 to 160 kgf·cm)
30.0 to 35.0 N·m
12.5 to 16.0 N·m
(300 to 350 kgf·cm)
(125 to 160 kgf·cm)
CAUTION
CAUTION
3-way
valve
En-14
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