Mitsubishi Electric EHSC-VM6A Service Manual page 40

Error code Title and display conditions
E0/E4 Main controller communication failure
(Reception error)
Error code E0 is displayed if main controller
does not receive any signal from the indoor
unit for ref. address "0" for 3 mins.
Error code E4 is displayed if indoor unit
does not receive any data from the main
controller for 3 mins or indoor unit does not
receive any signal from the main controller
for 2 mins.
E3/E5 Main controller communication failure
(Transmission error)
Error code E3 is displayed if the main con-
troller an not find an empty transmission
path and thus fails to transmit for 6 secs or
the data received bythe main controller is
different to what was sent (by the main con-
troller) 30 consecutive times.
Error code E5 is displayed if the FTC3 can
not find an empty transmission path for 3
mins and thus cannot transmit or the data
sent by the FTC3 is different to what was
expected 30 consecutive times.
E6 Indoor/outdoor communication failure
(Reception error)
Error code E6 is displayed if after the power
is switched ON to the indoor unit, the FTC3
board does not receive any signal or the
signal receivedis not complete for 6 mins, or
after a period of operation the FTC3 board
does not receive any signal or the signal
received is not complete for 3 mins.
Possible Cause
1 Contact failure with transmission cable
2
Wiring procedure not observed.
(Cable length/cable diameter/number of
indoor units/number of main controllers)
3
Fault on the indoor unit FTC3 board section
controlling Ref. address "0"
4 Fault with the main controller circuit board
5 Electrical noise causes interference with
transmission/reception of data for main con-
troller.
1
2 or more main controllers have been con-
nected to the FTC3.
2 Fault with main controller transmission/re-
ceiving circuit board
3
Fault with the main controller circuit board
4
Electrical noise causes interference with
transmission/reception of data for main con-
troller.
1 Contact failure/short circuit/miswiring
2
Fault with outdoor unit transmission/receiv-
ing circuit board
3 Fault with FTC3 transmission/receiving cir-
cuit board
4
Electrical noise causes interference with
FTC3-Outdoor unit transmission cable.
40
Diagnosis and action
1 Check connection cable for damage or loose
connections at the FTC3 and main controller
terminals.
2
Check main controller and FTC3 common
wiring max cable length 500 m.
Only use 2 core cable.
Only connect 1 main controller to 1 FTC3
indoor unit board.
3 5
to
If the problem is not solved by the above
measures then:
Turn the power to the indoor unit OFF and
then ON.
Power to both the indoor unit and outdoor
units should be switched OFF then ON. (This
may require switching 1 or 2 breakers de-
pending if the unit is powered independently
from the outdoor unit).
If the E4 code is still displayed the FTC3
and/or the main controller circuit board
should be replaced.
1
Only connect 1 main controller to 1 FTC3
indoor unit board.
2 4
to
Turn the power to the indoor unit OFF and
then ON.
Power to both the indoor unit and outdoor
units should be switched OFF then ON.
(This may require switching 1 or 2 breakers
depending if the unit is powered independ-
ently from the outdoor unit).
If the E3/E5 code is still displayed the FTC3
and/or the main controller circuit board
should be replaced.
Check the LED display on the outdoor unit
circuit board.
(Connect the A-control service tool, PAC-
SK52ST to test.) Refer to the outdoor unit
service manual for explanation of EA-EC
codes.
1 Check the connections on the indoor and
outdoor units have not become loose and
that the connecting cable is not damaged.
2 4
to
Turn the power to the indoor unit OFF and
then ON.
Power to both the indoor unit and outdoor
units should be switched OFF then ON.
(This may require switching 1 or 2 breakers
depending if the unit is powered independ-
ently from the outdoor unit).
If the E6 code is still displayed the FTC3
and/or the outdoor unit circuit board should
be replaced.