Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 305

[ IX Troubleshooting ]
Error
Error definition and error detec-
Code tion method
6608 No response
When no response command
is returned although acknowl-
edgement (ACK) is received
after transmission, an error is
detected.When the data is
transmitted 10 times in a row
with 3 seconds interval, an er-
ror is detected on the transmis-
sion side.
Note: The address/attribute
appeared on the display
on the remote controller
indicates the controller
where an error oc-
curred.
Cause
(1) The transmission line work of
one of the indoor unit, outdoor
unit, or the BC controller is per-
formed while the power is on,
the transmitted data will collide,
and the wave shape will be
changed.
(2) The transmission is sent and re-
ceived repeatedly due to noise.
(3) The transmission line voltage/
signal is decreased due to erro-
neous sizing of transmission
line.
Farthest:
200 m [656ft] or less
Remote controller wiring:}
10m [32ft] or less
(4) The transmission line voltage/
signal is decreased due to erro-
neous sizing of transmission
line.
Wire diameter:
2
1.25mm [AGW16] or less
- 296 -
Check method and remedy
1) When an error occurs at commission-
ing
Turn off the power sources of the out-
door unit, indoor unit, BC controller,
and LOSSNAY for 5 or more minutes,
and turn them on again.
-> When they return to normal opera-
tion, the cause of the error is the
transmission line work performed
with the power on.
If an error occurs again, check 2).
2) Check (3) and (4) on the left.
-> If the cause is found, correct it.
-> If no cause is found, check 3).
3) Check transmission wave shape/
noise on trans-mission line by follow-
ing <Investigation method of transmis-
sion wave shape/noise>.
Noise is the most possible cause of
the error "6602".