Mitsubishi Electric City Multi CMB-P1016NU-G, Service Handbook

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[
IX
Troubleshooting ]
2) Check the followings when the error "6607" occurs, or "HO" / "PLEASE WAIT"appears on the display on the remote
controller.
2. MA remote controller transmission
The communication between the MA remote controller and the indoor unit is performed with current tone burst.
(1) Symptoms caused by noise interference on the transmission line
If noise is generated on the transmission line, and the communication between the MA remote controller and the indoor
unit is interrupted for 3 minutes in a row, MA transmission error (6831) will occur.
(2) Confirmation of transmission specifications and wave pattern
Error code definition Remedy
7. The farthest distance of transmission line is 200m
[656ft] or longer.
Check that the farthest distance from the heat source unit to
the indoor unit and to the remote controller is within 200m
[656ft].
8. The types of transmission lines are different. Use the specified transmission line.
Type: Shielded wire CVVS/CPEVS/MVVS (For M-NET re-
mote controller)
Diameter: 1.25mm
2
[AWG16] or more
(Remote controller wire: 0.3-1.25mm
2
[AGW22-16])
9. Check the state of the choke coil on the transmis-
sion power supply circuit.
When resistance of the choke coil (L2) is between 0.5 and 2.6
ohm, the choke coil is normal.
When resistance (R3) on the heat source unit MAIN board is
1kohm 5%, it is normal. Connectors CNS1 and CNS2 must
be removed when resistance is measured.
10.Indoor unit or remote controller failure Replace the indoor unit controller board or the remote control-
ler.
A
(1)
, B(2) : No polarity
Across terminal No. 1-2
: Power supply (8.5V to 12VDC)
Satisfies the formula
12 msec/bit 5%
Voltage among terminals must
be between DC9 and 12 V.
TB15
A(1)
B(2) 1
2
MA remote controller
Transmission waveform (Across terminal No.1 - 2)
DC9~12V
Logic 1 Logic 0 Logic 1 Logic 1
12msec 12msec 12msec 12msec
Indoor unit