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First 2 digits Last 2 digits
(The display when the main power is turned on)
Press the "SELECT" button until "22" is displayed.
Press the "ENTER" button for more than 3 seconds.
The number of RB units for which automatic address
setting was successful will be shown in the first two digits.
The number of RB units for which it was unsuccessful will
be shown in the last 2 digits.
NOTE:
Incorrect configuration of the rotary switch "RB_AD" or
"REF AD" on the RB unit PC board or incorrect wiring may
lead to automatic address setting failure.
End
7.8. 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.
8. PIPE INSTALLATION II
Fig. A Connection system
In case of connected 1
Outdoor unit
outdoor unit
En-19
1: Function setting
Set to Function mode [F3].
(When [F4] to [F9] are displayed, continue to press
the "SELECT" button until [F3] is displayed.)
Automatic address setting for
RB units
Distance from termination resistor
(m)
0~100
~200
~300
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
Pressure regulating valve
Pressure gauge
RB unit
Vacuum
pump
Indoor unit
In case of con-
nected many
outdoor units
Fig. B
Cap
Table. A
Valve type
Liquid
Suction gas
Discharge gas
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
~400
~500
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.
Nitrogen
• 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).
Scale
• 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.
Outdoor unit
Outdoor unit
RB unit
Indoor unit
Charging cap
Valve
Open
Close
Close
Spindle
Cap
9.0 to 12.0 N·m
20.0 to 24.0 N·m
(90 to 120 kgf·cm)
(200 to 240 kgf·cm)
27.0 to 33.0 N·m
25.0 to 30.0 N·m
(270 to 330 kgf·cm)
(250 to 300 kgf·cm)
CAUTION
CAUTION
Pressure regulating valve
Pressure gauge
Nitrogen
Vacuum
Scale
pump
Spindle
Open
Hexagon
wrench
Charging cap
12.5 to 16.0 N·m
(125 to 160 kgf·cm)
12.5 to 16.0 N·m
(125 to 160 kgf·cm)
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