Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

Page: 259 / 436

[8-1 MA Remote Controller Problems ]
4
- chapter 8 BS_08_E
8 Troub
le
sho
oting Bas
ed on Ob
ser
ved
Sy
mp
toms
8-1-4 Air Conditioning Units Do Not Operate When the ON Button Is Pressed.
1. Phenomena
Even if the operation button on the remote controller is pressed, the indoor and the outdoor units do not start running.
2. Check method and remedy
YES
Blinking?
Is the remote
controller powered?
NO NO
NO
YES
YES
When all wires used for
grouping are disconnected, is at
least one of the LED2 on the
grouped indoor units lit?
YES
Check the daisy-chained cables for problems.
Is there an indoor unit on which LED2 is turned of
f?
If operated afterwards,
error 6602 or
6607 occurs.
Check the voltage between
the MA
remote controller
terminals (A
and B).
9-13VDC if the voltage is applied
and 0V if no voltage is applied.
Is LED1 on the indoor unit
control board lit?
(Blinks for 2 or 3 seconds
approximately every
20 seconds)
Does the number of the MA
remote controllers that are
connected to an indoor unit exceed the allowable
range (2 units)?
Blinking?
(T
urns on momentarily
approximately every
20 seconds)
*After correcting the error
, daisy-chain
the wire for the MA
remote controller again.
See section 8-1-1
The LCD
Does Not Light Up.
See section 8-1-1
The LCD
Does Not Light Up.
See sections
8-1-1
The LCD Does Not Light Up
and
8-1-2
The LCD Momentarily Lights
Up and
Then Goes Of
f.
See section 8-1-3 "HO"and
"PLEASE W
AIT"
Do Not Go Of
f the Screen.
See section 8-1-2
The LCD
Momentarily Lights Up and
Then Goes Of
f.
No.1 Refrigerant circuit check
See section 8-1-2
The LCD
Momentarily Lights Up and
Then Goes Of
f.
Check the malfunctioning
refrigerant circuit.
Check for the M-NET transmission line.
Replace the indoor unit control board.
Connect only two remote controllers to a system.
Check whether the screw on the wire is not loose.
Is LED2 on the indoor unit
control board blinking?
When the unit is operated with the remote controller
, will "ON"
appear on the display?
Is "Centralized"
displayed?
"HO"/"PLEASE W
AIT" keeps
blinking on the MA
remote controller
.
Is only the power source of the
indoor unit turn turned on again?
DEMAND by MELANS?
External thermo
input setting? (SW3-3=ON)
Does an error occur when
the power is reset?
Does the unit work properly
when the wire for the MA
remote controller is
daisy-chained again?
Is LED1 on the indoor
unit control board lit?
Does the MA
remote controller
work properly when it is connected
to the specified indoor unit?
Does an error occur when
the power is reset?
Running group operation with
the MA
remote controller?
Is the unit grouped
with the equipment package
indoor unit?
No fault with the equipment
package indoor unit?
Does an error occur when
the power is reset?
Check that no error occurs in other indoor units.
Check the indoor unit on which LED2 is lit.
All the indoor unit
power failure?
All the indoor unit
power failure?
Error display?
Error display?
Thermo is OFF?
Is operation possible?
Short circuit of the remote controller?
After turning the power on, check whether "HO"/
"PLEASE W
AIT" is displayed on the remote controller
.
After more than 20 seconds since
turning the power on, is LED2 check
of the indoor control board still
displayed?
Is the operation by MELANS
forbidden or the input from external control
equipment allowed (SWC=ON)?
Is the compulsory
thermo OFF (SW
A)
switch set to "2" or "3"?
Although No.1 refrigerant circuit
is normal, No.2 or No.3
refrigerant circuit remain stopped.
Running group operation with
the MA
remote controller?
Does the indoor unit make
an instantaneous stop?
Power supply voltage
AC198~264V?
NO
YES
NO NO NO NO
NO
NO
NO NO
When no error occurs
NO
NO
NO
Keep displaying for 5 or more minutes.
NO
NO NO NO
NO
NO NO NO
NO
NO
NO
NO
Check the power supply
.
Check the wire for the remote controller
.
NO
Replace the indoor unit control board.
NO
NO
NO NO
NO
Replace the MA remote controller
.
NO
Replace the remote controller or the indoor control board.
YES
Replace the indoor unit control board where an error occurs.
Keep the operation.
NO
NO NO NO
Keep the operation.
YES
YES
YES
YES
Power on
YES
Refer to 7-1 Error Code and Preliminary Error Code Lists for the displayed error code.
YES
Normal
T
urns of
f within approximately 5 minutes.
After the main power on, start the MA
remote
controller
. "HO" display will appear
.
YES
Normal
"Centralized" is displayed.
YES
Refer to the error code list.
YES
YES
YES
Normal
YES
Normal
(Is the thermo OFF signal input?)
YES
Set the SW
A
to "1".
YES
Refer to 7-1 Error Code and Preliminary Error Code Lists for the displayed error code.
YES
YES
YES
YES
Check the equipment package indoor unit.
YES
Replace the remote controller or the indoor control board.
Replace the indoor unit control board.
YES
YES
YES
Replace the remote controller or the indoor control board.
Normal
(Operate the unit with
external control equipment)
YES
YES
Replace the indoor unit control board.
Check the power supply
.
YES
YES
YES
YES
Check the voltage
between the MA
remote controller
terminal blocks (TB15) (A
and B).
9-13VDC if the voltage
is applied and 0V if no voltage
is applied.
NO
Disconnected wire for the remote controller?
Disconnected wire to
the terminal block?
Disconnected relay connector?
NO
Are the length or the diameter
of the wire for MA
remote controller
out of specification?
NO
YES YES
Use the wire that meets the specification.
Replace the wire for the MA
remote controller
.
YES
Check for the wire for the remote controller
.
Keep the operation.
YES
Replace the indoor unit control board.
YES
YES
YES
Power on
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