Mitsubishi Electric PURY-P120Y(T)HMU-A, Service Handbook

Page: 245 / 387

[
IX
Troubleshooting ]
- 236 - HWE0803A 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
LOSS-
NAY
(LC) M-NET re-
mote controller
(RC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmission to
LC (1) Factors (1) through (5) in the
"Factors in system with one
outdoor unit" (When perform-
ing an interlocked operation
of the LOSSNAY unit and the
indoor units that are connect-
ed to different outdoor units.) 1) Turn off the power source of
LOSSNAY for 5 or more min-
utes, and turn it on again. If the
error is accidental, it will run
normally.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 power
source of one of the outdoor
units has been shut off. 3) Same cause as that for indoor
unit described in 3)
(4) The male power supply con-
nector of the outdoor unit is
not connected to the female
power supply switch connec-
tor (CN40).
(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 central-
ized control.
If an error occurs, after the
unit runs normally once, the
following causes may be con-
sidered.
Œ
Total capacity error
(7100)
Œ
Capacity code error
(7101)
Œ
Error in the number of
connected units (7102)
Œ
Address setting error
(7105)