Mitsubishi Electric CITY MULTI PUHY-P400YEM-A Service Handbook page 175

Checking
Meaning, detecting method
code
6608 No response error
Though acknowledgement of re-
ceipt (ACK) is received after
transmission, no response com-
mand is returned.
Detected as error by transmission
side when the same symptom is
re-peated 10 times with an inter-
val of 3 seconds.
Note:
The address/attribute
shown on remote control-
ler indicates the control-
ler which has detected
error.
Check code
6831 MA
1. Communication between
communication,
the MA remote
No-reception
controller and the
error
indoor unit is not done
properly.
2. No proper data has been
received for 3 minutes.
6834 MA
1. Communication between
communication,
the MA remote
Start bit error
controller and the
indoor unit is not done
properly.
2. No proper data has
been received for 2
minutes.
6832 MA
1. Communication between
communication,
the MA remote controller
Synchronization
and the indoor unit is not
recovery error
done properly.
2. When transmission is
impossible because the
emptiness of the transfer
path cannot be checked.
6833 MA
1. Communication between
communication,
the MA remote controller
Transmission
and the indoor unit is not
/reception
done properly.
hardware error
2. When the transmitted
data is received at the
same time and compared,
the different state
continues 30 times.
Cause
1) At the collision of mutual transmis-
sion data when transmission wiring
is modified or the polarity is
changed while turning the power
source on, the wave shape changes
detecting error.
2) Repeating of transmission error due
to noise.
3) Damping of transmission line volt-
age/signal due to exceeding of the
acceptable range for transmission
wiring.
• Farthest
• RC wiring
4) Damping of transmission voltage/
signal due to improper type of
transmission line.
• Wire size : More than 1.25mm
Meaning and
detection means
1) The remote control line of the
MA remote controller or the
indoor unit is in poor contact.
2) All remote controllers are slaves.
3) The wiring specifications are not
observed.
1. Wire lingth
2. Wire thickness
3. Number of remote controllers
4. Number of indoor units
4) After the remote controller is
connected, disconnection of the
remote controller without
resetting the power.
5) Noise enters the transfer path of
the remote controller.
6) The transmission/reception circut
of the remote controller of the
indoor unit is poor.
7) The transmission/reception circut
of the remote controller is
defective.
1) The remote control line of the
MA remote controller or the
indoor unit is in poor contact.
2) It is set on two or more main
remote controllers.
3) The indoor unit addres is set
twice.
4) Noise enters the remote
controller line.
Indoor unit:
3 minutes
5) The wiring specifications are not
Remote controller: observed.
6 seconds
1. Wire length
2. Wire thickness
3. Number of remote controllers
4. Number of indoor units
6) The transmission/reception
circuit of the remote controller
is defective.
Checking method & Countermeasure
a) Generation at test run.
Turn off the power sources of OC unit
unit for more than 5 minutes simultaneously,
and make them again.
Returning to normal state means the trouble
detection due to transmission line work while
powering.
b) Check 3) and 4) of the causes left.
c) Investigate the transmission wave shape/noise
on transmission line according to <Investigation
Less than 200m method of transmission wave shape/noise>.
Less than 10m
Much possibility of a noise if 6602 is generated.
2
Factor
(1) Check the transmision lines of the
(2) Check the power supply to the main
(3) Check whether the tolerable range
(4) Check the main/slave setting of the
(5) Diagnose the remote controller.
(6) Check the transmision waveform
(7) If no problem is present in items.
-172-
and IC
Checking method and remedy
indoor unit and MA remote
controller for disconnection and
looseness.
power and remote controller lines.
of the MA remote controller line is
exceeded or not.
MA remote controller.
(Remote controller IM description)
Result:
[OK]: No problem in the remote
controller
(wiring specifications
check)
[NG]: Replace the remote
controller.
[6832, 6833, ERC]:
The noise is the cause.
(To (6))
and noise on the transmission
signal of MA remote controller line.
(1) to (6) above, replace the indoor
controller board or MA remote
controller.
The following states can be checked
from LED1 and LED2 on the indoor
controller board.
• LED1 is lit at the same time.
The main power is supplied to
the indoor unit.
•
LED2 alone is lit.
Power is supplied to the MA
remote controller line.