Troubleshooting Method - Toshiba MMW-AP0481CHQ-E Service Manual

8-2. Troubleshooting method

The remote controllers (main remote controller) and the interface P.C. board of an outdoor unit are provided
with an LCD display (remote controller) or a 7-segment display (outdoor interface P.C. board) to display
operational status. Using this self-diagnosis feature, the trouble site / trouble part may be identified in the event
of a trouble by following the method described below.
The list below summarizes check codes detected by various devices. Analyze the check code according to
where it is displayed and work out the nature of the trouble in consultation with the list.
• When investigating a trouble on the basis of a display provided on the indoor remote controller.
See the "main remote controller display" section of the list.
• When investigating a trouble on the basis of a display provided on an outdoor unit - See the "Outdoor 7-
segment display" section of the list.
List of check codes (indoor unit)
(Trouble detected by indoor unit)
Check code
Outdoor 7-segment display
Main remote
controller
display
A01 A01 Detected indoor nuit No.
A02 A02 Detected indoor nuit No.
A04 A04 Detected indoor nuit No.
E03 —
E04 —
E08 E08 Duplicated indoor address
E10 —
E18 —
F01 —
F03 —
F25 —
F26 —
F29 —
L03 —
L07 —
L08 L08
L09 —
L20 —
L30 Detected indoor unit No.
L30
P31 —
Typical trouble site
Sub-code
Flow switch operation trouble
Water temperature decrease
trouble
Activation of water heat
exchanger frost protection
Indoor-remote controller periodic
—
communication trouble
Indoor-outdoor periodic
—
communication trouble
Duplicated indoor address
Indoor inter-MCU communication
—
trouble
Trouble in periodic
—
communication between indoor
header and follower unit
Indoor heat exchanger
—
temperature sensor (TCJ) trouble
Indoor heat exchanger
—
temperature sensor (TC1) trouble
Water inlet temperature sensor
—
(TWI (TA)) trouble
Water outlet temperature sensor
—
(TWO (TC2)) trouble
— P.C. board or other indoor trouble Indoor EEPROM is abnormal (some other trouble may be detected).
Duplicated indoor group header
—
unit
Connection of group control cable
—
to stand-alone indoor unit
— Indoor group address not set
— Indoor capacity not set
— Duplicated central control address There is duplication in central control address setting.
Indoor external trouble input
(interlock)
— Other indoor unit trouble
IPDU: Intelligent Power Drive Unit (Inverter P.C. board)
Indoor unit (including Hot Water Module)
When water flow rate is reduced.
Water temperature continued the low status regardless of that
the water-heater and water pump is operating.
Frost protection for water heat exchanger is activated
Communication from remote controller or network adaptor has
been lost (so has central control communication).
Signals are not being received from outdoor unit.
Indoor unit detects address identical to its own.
MCU communication between main controller and motor
microcontroller is trouble.
Periodic communication between indoor header and follower units
cannot be maintained.
Heat exchanger temperature sensor (TCJ) has been open /
shortcircuited.
Heat exchanger temperature sensor (TC1) has been open /
shortcircuited.
Water inlet temperature sensor (TWI (TA)) has been open /
shortcircuited.
Water outlet temperature sensor (TWO (TC2)) has been open /
shortcircuited.
There is more than one header unit in group.
There is at least one stand-alone indoor unit to which group
control cable is connected.
Address setting has not been performed for one or more indoor
units (also detected at outdoor unit end).
Capacity setting has not been performed for indoor unit.
Unit shutdown has been caused by external trouble input (CN80).
Follower unit cannot be operated due to header unit alarm (E03 /
L03 / L07 / L08).
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Description of trouble