Mitsubishi Electric PURY-P120TJMU-A, Service Handbook, Page: 259 / 411

[
IX
Troubleshooting ]
- 250 - HWE0913A 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
(2) Grouping of units in a system with multiple outdoor units
6607
Error
source
address
Error display
Detection
method
Cause Check method and remedy
Outdoor
unit
(OC) ME remote
controller (RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmission to
OC Same cause as that for system
with one outdoor unit Same remedy as that for sys-
tem with one outdoor unit
BC con-
troller
(BC) ME remote
controller
(RC)
MA remote
controller
(MA) No acknowl-
edgement
(ACK) at IC
transmission to
BC Same cause as that for system
with one outdoor unit Same remedy as that for sys-
tem with one outdoor unit
Indoor
unit
(IC) ME remote
controller (RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at RC
transmission to
IC (1) Same causes as (1) - (5) for sys-
tem with one outdoor unit 1) Turn off the power sources of
the outdoor and indoor units
for 5 or more minutes, and turn
them on again. If the error is
accidental, the will run normal-
ly.If not, check the cause 2).
(2) Disconnection or short circuit of
the transmission line for the out-
door unit on the terminal block for
centralized control line connection
(TB7) 2) Check the causes of (1) - (5). If
the cause is found, correct it. If
no cause is found, check 3).
(3) When multiple outdoor units are
connected and the power source
of one of the outdoor units has
been shut off. 3) Check the LED displays for
troubleshooting on other re-
mote controllers whether an
error occurs.
(4) The male power supply connector
of the outdoor unit is not connect-
ed to the female power supply
switch connector (CN40). If an error is found,
-> If an error is found, check
the check code definition, and
correct the error.
If no error is found,
-> Indoor unit board failure
(5) The male power supply connec-
tors on 2 or more outdoor units
are connected to the female pow-
er supply switch connector
(CN40) for centralized control.
If an error occurs, after the unit
runs normally once, the following
causes may be considered.
Œ
Total capacity error (7100)
Œ
Capacity code error (7101)
Œ
Error in the number of con-
nected units (7102)
Œ
Address setting error (7105)