34
OCH721A
<M-NET communication error>
Check code Abnormal points and detection method
Cause
judgment and action
A0
(6600)
Address duplicate definition
This error is displayed when transmission
from the units of same address is detected.
Note: The address and attribute displayed
at remote controller indicate the
controller that detected abnormality.
1
There are 2 or more same
address of controller of out-
door unit, indoor unit, FRESH
MASTER, or LOSSNAY.
2
Noise has entered into trans-
mission signal and signal was
transformed.
Search the unit with same address as abnormal-
ity occurred. If the same address is found, turn off
the power supply of outdoor unit and indoor unit
and FRESH MASTER or LOSSNAY at the same
time for 2 minutes or more after the address is cor-
rected, and turn the power on again.
Check transmission waveform or noise on trans-
mission wire.
A2
(6602)
Hardware error of transmission processor
Transmission processor intended to transmit
“0”, but “1” appeared on transmission wire.
Note: The address and attribute display
at remote controller indicate the
controller that detected abnormality.
1
Error is detected if waveform is trans-
formed when wiring works of trans-
mission wire of outdoor unit, indoor
unit, FRESH MASTER or LOSSNAY
are done, or polarity is changed with
the power on and transmission data
collide each other.
2
Defective transmitting receiving
circuit of transmission processor
3
Transmission data is changed by
the noise on transmission.
1
If the works of transmission wire is done
with the power on, turn off the power supply
of outdoor unit and indoor unit and FRESH
MASTER or LOSSNAY at the same time for
2 minutes or more, and turn the power on
again.
2
Check transmission waveform or noise on
transmission wire.
A3
(6603)
BUS BUSY
1. Overtime error by collision damage
Abnormal if transmitting signal is not
possible for 8–10 minutes continuously
because of collision of transmission.
2. Data could not reach transmission wire
for 8–10 minutes continuously because
of noise, etc.
Note: The address and attribute displayed
at remote controller indicate the con-
troller that detected abnormality.
1
Transmission processor could
not transmit signal because short
cycle voltage of noise and the like
have entered into transmission
wire continuously.
2
Transmission quantity has
increased and transmission is
not possible because there was
wiring mistake of terminal block
for transmission wire (TB3) and
terminal block for central control
(TB7) in outdoor unit.
3
Transmission are mixed with oth-
ers and occupation rate on trans-
mission wire rose because of
defective repeater (a function to
connector or disconnect transmis-
sion of control and central control
system) of outdoor unit, then
abnormality is detected.
1
Check if transmission wire of indoor unit,
FRESH MASTER, LOSSNAY, or remote con-
troller is not connected to terminal block for
central control (TB7) of outdoor unit.
2
Check if transmission wire of indoor unit,
FRESH MASTER or LOSSNAY is not con-
nected to terminal block for transmission wire
of outdoor unit.
3
Check if terminal block for transmission wire
(TB3) and terminal block for central control
(TB7) are not connected.
4
Check transmission waveform or noise on
transmission wire.
A6
(6606)
Communication error with communica-
tion processor
Defective communication between unit pro-
cessor and transmission processor
Note: The address and attribute display at
remote controller indicate the control-
ler that detected abnormality.
1
Data of transmission proces-
sor or unit processor is not
transmitted normally because
of accidental trouble such as
noise or lightning surge.
2
Address forwarding from unit
processor is not transmitted
normally because of defective
transmission processor hard-
ware.
Turn off the power supply of outdoor unit and
indoor unit and FRESH MASTER or LOSSNAY
at the same time for 2 minutes or more, and turn
the power on again. System returns to normal
if abnormality was accidental malfunction. If the
same abnormality generates again, abnormality-
generated controller may be defective.
Check code Abnormal points and detection method
Cause
judgment and action
PL
Abnormal refrigerant circuit
During Cooling, Dry, or Auto Cooling
operation, the following conditions are
regarded as failures when detected for 1
second.
a) The compressor continues to run for 30
or more seconds.
b) The liquid pipe temperature or the
condenser/evaporator temperature is
167˚F [75
:
] or more.
These detected errors will not be
cancelled until the power source is
reset.
1
Abnormal operation of 4-way
valve
2
Disconnection of or leakage in
refrigerant pipes
3
Air into refrigerant piping
4
Abnormal operation (no rotation)
of indoor fan
· Defective fan motor.
· Defective indoor control board.
5
Defective refrigerant circuit
(clogging)
1
When this error occurs, be sure to replace
the 4-way valve.
2
Check refrigerant pipes for disconnection or
leakage.
3
After the recovery of refrigerant, vacuum dry
the whole refrigerant circuit.
4
Refer to “10-6. HOW TO CHECK THE
PARTS”.
5
Check refrigerant circuit for operation.
To avoid entry of moisture or air into
refrigerant circuit which could cause
abnormal high pressure, purge air in
refrigerant circuit or replace refrigerant.
Note: “Indoor unit” in the text indicates M-NET board in outdoor unit.
