Panasonic Cu W18bbp5 Cu 24bbp5 Cu W34bbp8 Cu W43bbp8 Series Repair Manual

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							18.1.1. Operation
 
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Simultaneous air conditioning of wide spaces and corners is
possible. Indoor units with different horsepower can even
be used in combination.
 
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Master units and slave-units can be set automatically in twin
systems. No address setting is necessary.
 
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Multiple indoor units can be operated simultaneousl y with a
single remote control unit. Note that individual operation is
not possible.
18 TWIN OPERATION
18.1. TWIN
(Twinoperation setting)
 
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The master units and slave units are set automatically when the power is turned on. At this time, the indoor unit which is
connected to the remote control unit becomes the master unit.
(If automatic setting is not possible, carry out the settings manua lly.)
 
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No distinction is made between master units and slave units (slave unit 1) at the indoor or remote control.
 
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Install the remote control unit to the master unit. (It cannot be connected to slave units.)
If indoor unit models with louvres and models without louvres have been connected together, use an indoor unit with louvres
as the master unit.
 
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The remote control thermostat can also be set.
 
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Optional circuit boards can only be installe d to the master unit.
 
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Setting the master unit and slave units can also be carried out manua lly by using DIP switches. However, manua l settings will
alwaystake priority. If you have made manua l settings but would like to return to using automatic settings, set all slave unit DIP
switches (refer to the table below) to the OFF position, and then press the ADDRESS RESET switch on the outdoo r unit (SW3
on the outdoor unit printed circuit board).
(Do not mix manua l settings and automatic settings.)
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							Automatic address setting fortwinsystem
Procedure:Turn on the power supply for the indoor and outdoor units.
Operation:Automatic address setting will start 10 to 30 seconds after the power supply is turned on, and will be completed after about 1
minute.
If the power supplies for the indoor unit and outdoor unit cannot be turned on at the same time, turn on the power supply for the
outdoor unit, the indoor unit which is connected to the remote control, and then the other indoor units in that order.
If the order of turning on the power supply is incorrect, the master unit setting may overlap. In such a case, turn on the power supplies
for all units in the correct order as given above, or carry out a twin/triple automatic address reset (press dip switch 3 on the outdoor
unit continuously for 4 seconds or longer).
 
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The indoor unit which is connected to the remote control unit (receptor) will have priority for becoming the master unit.
 
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The master unit thermostat will be used as the indoor temperature thermostat. If the master unit thermostat is turned on, the
slave unit thermostats cannot be adjusted even if they happen to be on.
 
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DIP switch settings take priority in the setting of twin and triple addresses.
 
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If address setting using the DIP switches is carried out after automatic address setting has been carried out, use DIP switch
No.3 on the outdoor unit to carry out automatic address resetting.
 
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If you would like to designate a particular indoor unit as the master unit because no master unit has been set, use the DIP
switches on the slave units to make the setting.
If automatic address setting is carried out once and then the slave unit addresses are set, the addresses will then be stored inside the
EEPROM. Thus it is not necessary to repeat automatic address setting if the power is turned off and back on again.
DIP switch settings fortwinslave unit addresses
Procedure:Turn off the power supply, and then set DIP switch 1-8 to ON.
The unit will become slave unit 1.
Turn on the power supply.
Operation:The unit will operate as slave unit 1. Automatic address setting is not carried out at this time.
If the setting can be made while the power is still turned on, it is easier to mis-combine the setting with group settings. So, the
setting be made better while the power is turned off.
 
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Only slave unit addresses can be set in this way. Master unit setting is not possible.
 
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If you make the DIP switch settings after the power has been turned back on, carry out twin/triple automatic address resetting.
 
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Be sure to set DIP switch 1-8 to ON when setting twin/triple addresses. If DIP switch 1-1 is set to ON without setting 1-8 to ON
also, group addresses will be set instead, and the remote control open circuit error code (F26) will bedisplay ed.
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							Function Automatic address resetting fortwinsystem s
 
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This clears the current twin addresses which have been set automatically , and causes automatic twin address setting to be
carried out once more.
Procedure:Press the ADDRESS RESET switch SW3 (push button switch) on the outdoor unit circuit board continuously until LEDs 2 to 8 on
the outdoor unit circuit board are all illuminated (takes approx. 3.5 seconds).
Operation:The outdoor unit will reset the addresses for the indoor units which it is connected to, and will send an instruction to carry out
automatic address setting again. If the indoor unit DIP switches have not been manually set for twin address setting, the indoor
units receive this command and they then clear their existing settings and carry out automatic address setting.
If an indoor unit has had its address set by the DIP switch (DIP switch 1-8 is ON), or if the remote control unit is connected to one
of the indoor units, then the addresses for those indoor units cannot be reset.
 
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The indoor units will not run for approximately 1 minute while automatic twin address resetting is being carried out.
 
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Do not turn off the power supply for at least 1 minute afterautomatic twin address resetting has been carried out.
18.2. Piping connections
 
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The following table shows the pipe diameters for a twin-type system.
Outdoor unit main pipe diameter (mm)Indoor unit combinations
34BBIndoor unit capacity (HP)18BD318BD3
Liquid side:ø 9.52Branch pipe
diameterLiquid sideø 6.35ø 6.35
Gas side:ø 15.88Gas sideø 12.7ø 12.7
43BBIndoor unit capacity (HP)24BD324BD318BD328BD3
Liquid side:ø 9.52Branch pipe
diameterLiquid sideø 6.35ø 6.35ø 6.35ø 9.52
Gas side:ø 19.05Gas sideø 15.88ø 15.88ø 12.7ø 15.88
 
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The following table shows the equivalent pipe lengths and height differences for twin systems
Equivalent lengthL + la + lbWithin 50 m
Branch pipe diameterla, lbWithin 15 m
Branch pipe differencela - lbWithin 10 m
Height differenceH1Within 30 mHeight difference between indoor unitsH2Within 1 m
NOTE :
 1. Use the main pipe to gain any rise or fall required for the pipes.
 2. The numbe r of bends should be 8 or less in a single system (L + la, L + Ib), and 15 or less overall.
 3. Branch pipes should be positioned horizon tally.
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The branch pipe should be horizon tal to or perpendicular to the indoor unit.

 
Installing branch pipes
18.3. Refrigerant charging
 
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For twin systems
The pipe length is the total of the branch pipe (L) and the junction pipes (Ia→
tIb→
t Ic in order from the thickest diameter). At
the point where the pipe length exceed s 30 m, determine the amoun t of refrigerant for the remaining liquid-side pipe diameters
and pipe lengths from the following table in order to charge the system.
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							18.4. Wiring
Whenboth indoor and outdoor unit draw power
(Example: 3 Phase power supply model)
When only theoutdoor unit draws power
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							19 WIRING MISTAKE PREVENTION
Improved quality of installation work through adoption of an “Connection error prevention” circuitwhichpreven ts wiring
mistakes
Conne ction errors with the control wires and the power supply wires will not only contribute to burning-out of the control circuit
board, but can also cause large-scale working losses and affect reliability. If a circuit board with a “Connection error prevention”
circuit is used, the relay will not operate if the wires have been connected incorrectly, so that current will not flow to the control
circuit board. This is designed principally toeliminate human error at the installa tion site.
Prevention of connection errors
These units are equipped with connection error prevention circuits. If the units do not operate, it is possible that the connection error
prevention circuits have operated. In such cases, check that the power supply wires (connected to terminals 1
and 2and the
control wires (connected to terminals 3
and 4) are connected correctly. If they are connected incorrectly, connnectthem
correctly. Normal operation should thencommence.
 
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Do not short the remote control wires to each other. (The protection circuit will be activated and the units will not operate.) Once
the cause of the short is eliminated, normal operation will then be possible.
NOTE:
 
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W ait one minute after turning on the indoor unit power supply before operating theremote control.
 
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If nothing at all appears in the remote control LCD, check the powersupply for the indoor unit.
Refer to “TROUBLE SHOOTING”.
NOTE:
Never do any of the following, as doing so may damage the printed circuit board.
 
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Do not connect anythin g except a relay to the timer input or fan speed output (connector CNT1 on printed circuit board).
 
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Do not connect U-NET transmission wires to terminals 3 and 4 of the indoor and outdoor units. (*1)
 
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Do not connect U-NET transmission wires to terminals A and B of the remote control.
(*1) U-NET transmission wires are the communication wires used for the central controller.
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