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Trouble diagnosis
8
84
Remote
Description
Controller
Display
E16
Auto address setting
alarm (too many units)
E18
Faulty Communication in
Group Control Wiring
E20
No indoor units at auto
address setting.
F01
E1 sensor trouble
F02
E2 sensor trouble
F03
E3 sensor trouble
F10
TA sensor trouble
F11
BL sensor trouble
F29
EEPROM of AHU unit
failure
L03
Duplication of group con-
trol's main indoor unit
L07
Group control setting
trouble
L08
Indoor unit address not
set
L09
Indoor unit capacity not
set
L13
Indoor unit type setting
error
P09
Improper wiring of ceiling
panel connector
P10
Float switch activated
P12
DC fan protection active
P14
O2 sensor alarm
P31
Other indoor unit
Detailed Explanation
It is judged an error when the total capacity of indoor units is too high or the total number of indoor
units is too many.
• The total capacity of AHU units is too high.
• The total number of AHU units is too many.
• When making group control of the different refrigerant system, the steps to turn on the systems
one at a time has not been performed.
When the main remote controller cannot communicate with a sub remote controller in the remote
control group.
It is judged an error if a sub remote controller in a remote control group fails to communicate with
the main remote controller for a period of 3 minutes.
• An indoor unit within the control group does not have its power on.
• The CHK pin and TEST pin on the indoor unit in the control group are shorted.
• The DISP pin of an indoor unit sub remote controller in the control group is shorted.
• Remote control group wiring is open.
• More than one indoor unit in the control group is set to Main.
• An indoor unit in the control group is set to Separate.
When auto address setting was performed, no indoor units were recognised.
• Indoor unit address is not properly assigned.
• Indoor unit power is OFF.
AHU unit E1 coil temperature sensor not connected or defective or not set (R < 30Ω or R > 330kΩ)
AHU unit E2 coil temperature sensor not connected or defective or not set (PACi) (R < 30Ω or
R > 330kΩ)
AHU unit E3 coil temperature sensor not connected or defective or not set (ECOi) (R < 30Ω or
R > 330kΩ)
AHU unit TA (suction air) temperature sensor not connected or defective or not set (R < 24Ω or
R > 270kΩ)
AHU unit BL (discharge air) temperature sensor not connected or defective or not set (ECOi)
(R < 24Ω or R > 270kΩ)
EEPROM of the AHU unit main PCB failure
An error is determined when the nonvolatile memory (EEPROM) on the AHU control board cannot
be read or written.
Duplication of main indoor unit address in group control
• When remote controller group wiring is changed after auto-addressing is complete.
• When multiple main units are set in remote controller detailed settings mode.
Group control wiring is detected for an indoor unit set as individual controlled unit
An error is determined when remote controller group wiring includes an indoor unit set for independ-
ent operation.
• When remote controller group wiring is set up after auto-addressing is complete.
• When group settings for an indoor unit wired into a remote controller group are changed to "Inde-
pendent" in remote controller detailed settings mode.
AHU address (indoor unit address) is not set
• When the indoor unit address was not set when new non-volatile memory (EEPROM) was
installed.
• When indoor unit address in the remote controller detailed settings mode is "invalid."
AHU capacity (indoor unit capacity) is not set
• When the indoor unit capacity setting was forgotten after installing a new nonvolatile memory
(EEPROM).
• In the remote controller detailed settings mode, the indoor unit capacity is "invalid".
Type of indoor / outdoor units is different
ECOi: AHU main PCB (A1) PNL contacts 1 & 3 open
PACi: AHU main PCB (A1) LM contacts 17 & 18 open
AHU terminal board FS1 & FS2 is open
Incorrect parameter settings, type of indoor set as DC fan model (by connector DCM (CN141) on
AHU main PCB A1)
AHU terminal board EX1 & EX2 closed contact
Other indoor unit in group control has an alarm.
Survey the indoor unit that alarms other than "P31" in the indoor unit group and specify the causes
of failure.
AHU Kit – Installation Instructions – 07/2023
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