Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 1076

FDC-HKXR
(2) Effect of noise
Reference
• When noises inturude into the remote controller.
Abnormal or irregular display such as the flashing of irrelevant display (lamp) (for example, LEDs of cooling and heating
illuminated simultaneously or the like) is observed even if the remote controller is not operated or the remote controller and,
as the result, the operation of units may be disabled or similar abnormal phenomenons are observed.
• When noises intruded into the microcomputer of printed circuit board; State of operation becomes abnormal such as the units
perform irregular operation while the remote controller is not operated, the operation cannot be stopped with the remote
controller, etc.
Electro magnetic noise prevention(example)
• Cover the entire surface of control box or
the inside of unit cover with the cover foil
or cover the enitre unit with a wire net.
Remote controller wire
Use the shield or
twist pair wires
Put in a steel case
Remote controller
Separate from cutting machine as for as
possible. This is very effective because
the effect of noise is in inverse
proportion to 1.5 times of distance.
Beware of noises
transmitted via air.
(b) Eroor diagnosis procedures at the indoor unit side
The error diagnosis for indoor units is the same as for the Multi KX Series. For details, please refer to the section for the KX
Series found on pages 910 to 917.
(c) Error diagnosis procedures at the outdoor unit side
At the error diagnosis related to the outdoor unit, check at first the error code of remote controller and the illumination patterns of
norma l and inspection display lamps in the same manner as the case of indoor unit.
Then estimate the outline, the cause and the location of error based on the pattern and proceed to the inspection and repair. Since
the self diagnosis function by means of the microcomputers of indoor/outdoor units provide the judgement of error of
microcomputers them selves irregularity power supply line, overload, etc. caused by the installation space, inadequate volume of
refrigerant etc., the location and cause of trouble will be discovered without difficulty.
In addition, the display lamps error code of indoor/outdoor units is kept flashing, (except when the power supply is
interrupted)after the irregularity is automatically recovered to give irregularity information to the service presonnel. If any mode
of higher priority than the error retained in memory occurs after the reset of error, it is switched to that mode and saved in the
memory.
(i) Replacement parts assembly related to the outdoor unit PCB
Outdoor unit PCB, outdoor unit inverter PCB, power transistor module, diode module, capacitor, reactor, noise filter, thermistor,
1074
Interisified shielding
of control section
l
2
Shut off electrically the
noise source or put it in
a shield room.
Signal wire
Outdoor
(Indoor unit)
unit
l
1
Unless it has a sufficient current
capacity, mini split current drops
Power
momentarily at the start/stop of
cable
cutting machine.
Distribution
board
Avoid
distribution board to prevent troubles
by the power source propagation.
Install the line filter at the power
supply of cutting machine of mini split
(Positive grounding is necessary.)
•Insert in a steel pipe to shield.
Make a positive
ground
supply from the same