Mitsubishi Electric City Multi PQHY-P72 Service Handbook page 248

(1) System with one heat source unit
Error Code
6607 No ACK abnormality
Error
Error dis- Detection
source ad-
play
dress
Heat M-NET re- No ac-
source mote con- knowl-
unit troller (RC) edgement
(OC) MA remote (ACK) at
controller BC trans-
(MA) mission to
OC
BC control- No ac-
M-NET re-
ler (BC) mote con- knowl-
troller (RC)
edgement
MA remote
(ACK) at IC
controller
transmis-
(MA)
sion to BC
Indoor M-NET re- No ac-
unit mote con- knowl-
(IC) troller (RC)
edgement
MA remote (ACK) at
controller RC trans-
(MA) mission to
IC
LOSSNAY M-NET re- No ac-
(LC) mote con- knowl-
troller (RC) edgement
MA remote (ACK) at IC
controller transmis-
(MA) sion to LC
M-NET re- M-NET re- No ac-
mote con- mote con- knowl-
troller (RC) troller (RC) edgement
(ACK) at IC
transmis-
sion to RC
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 transmitted six times in a row with 30 seconds
interval, the error is detected on the transmission side.)
Note: The address/attribute appeared on the display on the remote controller
indicates the controller which did not provide the response (ACK).
Cause
method
(1) Contact failure of transmission line
of OC or BC
(2) Decrease of transmission line volt-
age/signal by exceeding accept-
able 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
[AWG16] or more
(4) Heat source unit main board fail-
ure
(5) Power circuit failure of heat
source unit
(1) When BC controller address is
changed or modified during opera-
tion.
(2) Faulty or disconnected transmis-
sion wiring of BC controller
(3) Disconnected connector of BC
controller (CN02)
(4) Faulty control board of BC control-
ler
(1) When IC unit address is changed
or modified during operation.
(2) Faulty or disconnected IC trans-
mission wiring
(3) Disconnected IC connector
(CN2M)
(4) Indoor unit board failure
(5) M-NET remote controller failure
(1) The power source of LOSSNAY
has been shut off.
(2) When the address of LOSSNAY is
changed in the middle of the oper-
ation
(3) Faulty or disconnected transmis-
sion wiring of LOSSNAY
(4) Disconnected connector (CN1) on
LOSSNAY
(5) Controller failure of LOSSNAY
(1) Faulty transmission wiring at IC
unit side.
(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
- 239 -
Check method and remedy
Turn off the power source of the heat source
unit, and turn it on again. If the error is acci-
dental, it will run normally.
If not, check the causes (1) - (5).
Refer to 9.[4].-7-.(2) "Heat source unit trans-
mission power source circuit failure judg-
ment" for (5).
2
Turn off the heat source/indoor units for 5 or
more minutes, and turn them on again.
If the error is accidental, they will run nor-
mally. If not, check the causes (1) - (4).
Turn off the heat source/indoor units for 5 or
more minutes, and turn them on again.
If the error is accidental, they will run nor-
mally. If not, check the causes (1) - (5).
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).
Turn off the power source of the heat source
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).
[ IX Troubleshooting ]