Mitsubishi Electric PUHY-P120YHMU-A, Service Manual

Page: 207 / 326

[
IX
Troubleshooting ]
- 198 - HWE0804A 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) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmission to
OC Same cause as that for sys-
tem with one outdoor unit Same remedy as that for sys-
tem with one outdoor unit
Indoor
unit
(IC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at RC
transmission to
IC (1) Same causes as (1) - (5) for
system 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 outdoor unit on the termi-
nal block for centralized con-
trol 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 pow-
er source of one of the out-
door 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 con-
nector of the outdoor unit is
not connected to the female
power supply switch connec-
tor (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 con-
nectors on 2 or more outdoor
units are connected to the fe-
male power supply switch
connector (CN40) for cen-
tralized control.
If an error occurs, after the
unit runs normally once, the
following causes may be
considered.
ΠTotal capacity error
(7100)
ΠCapacity code error
(7101)
ΠError in the number of
connected units (7102)
ΠAddress setting error
(7105)