Mitsubishi Electric City Multi PUHY-HP144TSHMU-A, Service Handbook

Page: 162 / 265

[
IX
Troubleshooting ]
- 153 - HWE0716A GB
1. Error Code
No ACK error
2. Error definition and error detection method
The error is detected when no acknowledgement (ACK signal) is received after the transmission. (eg. When the data is trans-
mitted six times in a row with 30 seconds interval, the error is detected on the transmission side.)
The address/attribute appeared on the display on the remote controller indicates the controller which did not provide
the response (ACK).
3. System configuration
(1) System with one outdoor unit
6607
Error
source ad-
dress
Error display
Detection
method
Cause Check method and remedy
Outdoor
unit (OC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmis-
sion to OC (1) Contact failure of transmission
line of OC or IC Turn off the power source of the
outdoor unit, and turn it on
again.
If the error is accidental, it will
run normally. If not, check the
causes (1) - (4).
(2) Decrease of transmission line
voltage/signal by exceeding ac-
ceptable range of transmission
wiring.
Farthest:200 m [656ft] or less
Remote controller wiring:
10m [32ft] or less
(3) Erroneous sizing of transmission
line (Not within the range below).
Wire diameter:
1.25mm
2
[AWG16] or more
(4) Indoor unit control board failure
Indoor unit
(IC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at RC
transmis-
sion to IC (1) When IC unit address is changed
or modified during operation. Turn off the outdoor/indoor units
for 5 or more minutes, and turn
them on again.
If the error is accidental, they
will run normally.
If not, check the causes (1) - (5).
(2) Faulty or disconnected IC trans-
mission wiring
(3) Disconnected IC connector
(CN2M)
(4) Indoor unit controller failure
(5) M-NET remote controller failure
LOSSNAY
(LC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmis-
sion to LC (1) The power source of LOSSNAY
has been shut off. Turn off the power source of
LOSSNAY and turn it on again.
If the error is accidental, it will
run normally.
If not, check the causes (1) - (5).
(2) When the address of LOSSNAY
is changed in the middle of the
operation
(3) Faulty or disconnected transmis-
sion wiring of LOSSNAY
(4) Disconnected connector (CN1)
on LOSSNAY
(5) Controller failure of LOSSNAY
M-NET re-
mote con-
troller (RC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmis-
sion to RC (1) Faulty transmission wiring at IC
unit side. Turn off the power source of the
outdoor unit for 5 minutes or
more, and turn it on again.
If the error is accidental, it will
run normally.
If not, check the causes (1) - (4).
(2) Faulty wiring of the transmission
line for M-NET remote controller
(3) When the address of M-NET re-
mote controller is changed in the
middle of the operation
(4) M-NET remote controller failure