Mitsubishi Electric PQHY-P120THMU-A, Service Handbook

Page: 284 / 414

[
IX
Troubleshooting ]
- 275 - HWE09080 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
(3) System connected to the system controllers (MELANS)
6607
Error
source
address
Error display
Detection
method
Cause Check method and remedy
ME re-
mote con-
troller
(RC) ME remote
controller (RC)
System con-
troller (SC)
MA remote
controller (MA) No acknowl-
edgement
(ACK) at IC
transmission to
RC Same as grouping of units in a sys-
tem with multiple heat source units Same remedy as that for
grouping of units in a system
with multiple heat source
units
System con-
troller
(SC) No acknowl-
edgement
(ACK) at
MELANS
transmission to
RC 1. Error occurrence on some IC Same remedy as that for
system with one heat source
unit
(1) Same cause as that for system
with one heat source unit
2. Error occurrence on all IC in the
system with one heat source unit 1) Check the LED display for
troubleshooting on the heat
source unit.
(1) An error is found by the heat
source unit.
Total capacity error (7100)
Capacity code error (7101)
Error in the number of connected
units (7102)
Address setting error (7105)
Œ
If an error is found, check
the check code definition,
and correct the error.
Œ
If no error is found, check
the cause 2).
(2) Disconnection or short circuit of the
transmission line for the heat
source unit on the terminal block
for centralized control line connec-
tion (TB7) 2) Check (2) - (4) on the left.
(3) Turn off the power source of the
heat source unit
(4) Malfunction of electrical system for
the heat source unit
3. Error occurrence on all IC Check (1) - (4) on the left.
(1) Same causes as (1) - (4) described
in 2.
(2) When the power supply unit for
transmission lines is used and the
male power supply connector is
connected to the female power
supply switch connector (CN40) for
the transmission line for central-
ized control
(3) Disconnection or shutdown of the
power source of the power supply
unit for transmission line
(4) System controller (MELANS) mal-
function