Toshiba MMD-AP0071SH-C Service Manual page 87

Check code Check code name
[E20] / [42] Unit connected to other line
during automatic address
(d07 / AI-NET)
Sub-code: 01: Connection of outdoor in other line 02: Connection of indoor unit in other line
Separate the wire between lines according to address setup method.
Check code Check code name
[E23] / [15] Communication sending error
between outdoor units
(d07 / AI-NET)
Is there no miscabling or YES
disconnection on communication line
between outdoor units? ( 1)
NO
NO
Is connection of CN03 connector
on outdoor I/F P.C. board normal?
YES
YES
Is not main power of
outdoor unit turned off?
NO
Is the end terminal resistance NO
between outdoor units turned on?
(SW30 Bit 1)
YES
YES
Did power failure occur?
NO
YES
Is there no noise source, etc?
NO
Check outdoor I/F P.C. board.
Defect Replace
Cause of operation
When starting automatic indoor address, a
device in other line is connected.
Cause of operation
1. Inter-unit cable connection error between
outdoor units
2. Communication connector connection error
between outdoor units, I/F P .C. board error
3. End terminal resistance setup error between
outdoor units
Correct communication line.
Correct cabling of cable connector.
Turn on main power of outdoor unit.
Turn the end terminal resistance to ON.
Clear check code.
Check and eliminate noise, etc
(∗ ∗ ∗ ∗ ∗ 1) In this model, only one outdoor unit is provided to
one refrigerant line. Be sure to check there is no
communication connection with outdoor unit in the
other refrigerant line.
Check code Check code name
[E25] / [15] Duplicated address setup of
terminal outdoor units
(d07 / AI-NET)
Never set up the outdoor address manually.
Check code Check code name
[E26] / [15] Decrease of connected
outdoor units
(d07 / AI-NET)
Sub-code: No. of outdoor units which received signals normally
YES
Is outdoor unit setting backup?
NO
NO
Is main power of follower unit turned on?
YES
NO
Is communication line between
outdoor units connected normally?
YES
NO
Is communication connector (CN03)
between follower outdoor units connected?
YES
(∗ ∗ ∗ ∗ ∗ 1) How to clear the error
Check I/F P.C. board.
Set SW01/SW02/SW03 on I/F P .C. board of header unit to 2/16/1, and
push SW04 for 5 seconds or more. (7-segment display: [Er.] [CL])
• In this model, only one outdoor unit is provided to one refrigerant line. Be sure to check there is no communication
connection with outdoor unit in the other refrigerant line.
Check code Check code name
[E28] / [d2] Terminal outdoor unit error
(d07 / AI-NET)
Sub-code: Detected outdoor unit number
SAn error occurred on the terminal unit. Confirm the check code of the terminal unit using 7-segment display on the
I/F P.C. board of the terminal unit and check it according to the diagnostic procedure for each check code.
<How to specify the terminal outdoor unit on which error occurred>
Under condition that [E28] is displayed on the 7-segment display of the header unit, when pushing SW04 for 1
second or more, the fan of the outdoor unit which stopped due to the error rotates. If pushing SW05 alone, fan
running is released.
Cause of operation
Addresses are duplicated by manual setting of
outdoor address
Cause of operation
1. Outdoor unit backup setup
2. Outdoor power error
3. Communication line connection error between
outdoor units
4. Connector connection error for communication
5. Outdoor I/F P.C. board error
Clear the error, and then start operation. ( * 1)
Turn on the main power supply.
Correct connection of communication line.
Correct connector connection.
(Communication connector: CN03)
Cause of operation
Terminal unit error