Mitsubishi Electric CITY MULTI PQRY-P200YMF-C Service Handbook page 122

Checking
code
6607 No ACK error
System
Generating Display of
compo-
unit address trouble
sition
1 Heat Remote
source controller
unit (OC) (RC)
2 BC Remote
controller controller
(BC) (RC)
3 Indoor Remote
unit (IC) controller
(RC)
4 Remote Remote
controller controller
(RC) (RC)
Meaning, detecting method
When no ACK signal is detected in 6 continuous times with 30 second interval by
transmission side controller, the transmission side detects error.
Note: The address/attribute shown on remote controller indicates the controller
not providing the answer (ACK).
Detecting
method
No reply 1) Poor contact of transmission line of OC or BC.
(ACK) at 2) Damping of transmission line voltage/signal
BC by acceptable range of transmission wiring
transmis- exceeded.
sion to OC
Farthest
Remote controller wiring : Less than 10m
3) Erroneous sizing of transmission line (Not
within the range below).
Wire diameter
4) Faulty control circuit board of OC.
No reply 1) When Fresh Master address is changed or
(ACK) at IC modified during operation.
transmis- 2) Faulty or slipping off of transmission wiring of
sion to BC BC controller.
3) Slipping off of BC unit connector (CN02).
4) Faulty BC controller circuit board.
No reply 1) When IC unit address is changed or modified
(ACK) at during operation.
RC 2) Faulty or slipping off of transmission wiring of
transmis- IC.
sion to IC 3) Slipping off of IC unit connector (CN2M).
4) Faulty IC unit controller.
5) Faulty remote controller.
No reply 1) Faulty transmission wiring at IC unit side.
(ACK) at IC 2) Faulty transmission wiring of RC.
transmis- 3) When remote controller address is changed
sion to RC or modified during operation.
4) Faulty remote controller.
Cause
: Less than 200m
: 1.25mm 2 or more
–121–
Checking method & countermeasure
Shut down OC unit power source, and
make it again.
It will return to normal state at an ac-
cidental case.
When normal state can not be re-cov-
ered, check for the 1) ~ 4) of the cause.
Shut down both OC and BC power so-
urces simultaneously for 5 minutes or
more, and make them again.
It will return to normal state at an acci-
dental case.
When normal state can not be re-cov-
ered, check for the 1) ~ 4) of the cause.
Shut down both OC and BC power so-
urces simultaneously for 5 minutes or
more, and make them again.
It will return to normal state at an acci-
dental case.
When normal state can not be re-cov-
ered, check for the 1) ~ 4) of the cause.
Shut down OC power sources for 5 min-
utes or more, and make it again.
It will return to normal state at an acci-
dental case.
When normal state can not be re-cov-
ered, check for the 1) ~ 4) of the cause.