Mitsubishi Electric FRESH MASTER GUF-50RD4 Handbook page 16

Error code Error content
6607 Communication er-
ror (No ACK error)
6608 Communication
error (No answer
error)
Cause
System connected with MELANS
a) Malfunction only in some of the units
• Refer to the causes for the single
coolant system
b) Malfunction in all the indoor units and
Fresh Master units in one coolant
line
1 Causes of total capacity error
(7100)
2 Causes of capacity code setting
error (7101)
3 Causes of the number of connected
devices error (7102)
4 Causes of Address setting error
(7105)
5 Short circuit or disconnection of the
transmission cable to the terminal
block for central control (TB7) in the
outdoor unit
6 The outdoor unit is shut down.
7 Fault in the electrical system of the
outdoor unit
c) Malfunction in all the indoor units and
Fresh Master units
1 The above causes 1 to 7
2 The setting of the outdoor unit is
incorrect.
3 Wiring from the power supply unit to
the transmission cables is discon-
nected, or the power supply unit is
shut down.
4 Malfunction of the system controller
(MELANS)
1 The transmission cables were wired
or the polarity was changed with the
power ON.
2 A transmission error repeatedly occurs
due to noise or the like.
3 The voltage/signal in the transmission
cable drops because the length of the
transmission cable wiring is longer
than specified.
• Maximum extension:
500 m or less,
Power supply line must be 200 m
or less
• ME remote controller wiring:
10 m or less
4 The voltage/signal in the transmission
cable drops because the transmission
cable does not meet specification.
• Cable diameter: 1.25 to 2.0 mm
Refer to the remedy for the single coolant
system
Check the error display LEDs of the out-
door unit.
• When there is an error
See the error code, and follow the instruc-
tions described in the troubleshooting.
• When there is no error
Check the causes 5 to 7 written in the
left.
See the service manual of the outdoor unit.
Check the voltage of the transmission
cables for central control.
• When the voltage is 20 V DC or more
Check the causes 1 and 2 written in the
left.
• When the voltage is less than 20 V DC
Check the cause 3 written in the left.
See the service manual of the outdoor unit.
Simultaneously turn OFF the power of the
indoor units, Fresh Master, and the outdoor
units, and then, turn them ON again.
• When the system returns to normal
It means the error was detected because
the transmission cables were wired with
the power ON.
• If the system does not return to normal
Check the causes 3 and 4 written in the
left, and repair the troubled sections.
If none of the above causes applies,
inspect the transmission waveform and
noise in the transmission cable line. (If
the error 6602 occurs, noise will probably
be a cause.)
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Remedy