Mitsubishi Electric SRK100VNPZJX, Technical Manual

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'12 • PAC-T-174
(4) Troubleshooting at the outdoor unit
When troubleshooting the outdoor unit, firstly assess the overview of malfunction and try to presume the cause and the faulty
part by checking the error cord dispalyed on the remote controller and flashing pattern of indicator lamps (Red LED and Green
LED), and then proceed further inspection and remedy it.
Self-diagnosis system by microcomputor on indoor and outdoor PCB can assist to find the cause of malfunction smoothly by
making a diagnosis of not only the anomaly of microcomutor, but also the anomaly in power supply system, installation space,
overload resulting from improper charging amount of refrigerant and etc.
Unless the power is reset, the error log is saved in memory and the inspection indicator lamps on outdoor PCB keep flashing
after automatical recovering from malfunction.
After automatical recovering from malfunction, if any another error mode which has a higher priority than the previous error
saved in memory occurs, it is overwritten in memory and is displayed.
[Reset of power supply]
Be sure to avoid electrical shock, when replacing or checking the outdoor control PCB, because some voltage is still retained in
the electrolytic capacitor on the PCB even after shutting down tne power supply to the outdoor unit.
Be sure to start repairing work, after confirming that the Green LED on the PCB has been extiguished for more than 10
seconds after more than 3 minutes had been passed since power shut down, and reconfirming that voltage has been discharged
sufficiently by measuring the voltage (DC) between both terminals of electrolytic capacitor (C58) (Measurment of voltage
may be disturbed by the moisture-proof coating. In such case, remove the coating and measure it by taking care of avoiding
electrical shock)
(a) Module of part to be replaced for outdoor unit controller
Outdoor control PCB, Inverter PCB, Temperature thermistor (of outdoor heat exchanger, discharge pipe, outdoor air,
IPM and suction pipe), Fuses (for power supply and control PCB), Noise filter, Capacitor, Reactor and Transformer
(b) Replacement procedure of outdoor control PCB
Precautions for Safety
・
Since the following precaution is the important contents for safety, be sure to observe them.
WARNING and CAUTION are described as follows:
WARNING
Indicates an imminently hazardous situation which will result in death or serious
injury if proper safety procedures and instructions are not adhered to.
CAUTION
Indicates a potentially hazardous situation which may result in minor or moderate
injury if proper safety procedures and instructions are not adhered to.
WARNING
・
Securely replace the PCB according to this procedure.
If the PCB is incorrectly replaced, it will cause an electric shock or fire.
・
Be sure to check that the power source for the outdoor unit is turned OFF before replacing the
PCB. The PCB replacement under current-carrying will cause an electric shock or fire.
・
After finishing the PCB replacement, check that wiring is correctly connected with the PCB before
power distribution. If the PCB is incorrectly replaced, it will cause an electric shock or fire.
CAUTION
・
Band the wiring so as not to tense because it will cause an electric shock.
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