Troubleshooting Procedure; Troubleshooting At The Indoor Unit - Mitsubishi Heavy Industries SCM50ZS-S1 Technical Manual

■ Error log and reset
Error indicator
Remote control display
Red LED on indoor control PCB
■ Resetting the error log
• Resetting the memorized error log in the remote control
Holding down "CHECK" button, press "TIMER" button to reset the error log memorized in the remote control.
• Resetting the memorized error log
The remote control transmits error log erase command to the indoor unit when "VENTI" button is pressed while
holding down "CHECK" button.
Receiving the command, the indoor unit erase the log and answer the status of no error.

(2) Troubleshooting procedure

When any trouble has occurred, inspect as follows. Details of respective inspection method will be described on later pages.
Confirmation
of power
Trouble source
(Indoor/
outdoor unit)

(3) Troubleshooting at the indoor unit

With the troubleshooting, find out any defective part by checking the voltage (AC, DC), resistance, etc. at respective
connectors at around the indoor PCB, according to the inspection display or operation status of unit (the compressor does
not run, fan does not run, the 4-way valve does not switch, etc.), and replace or repair in the unit of following part.
(a) Replacement part related to indoor PCB's
Control PCB, power PCB, temperature sensor (return air, indoor heat exchanger), remote control and fuse
Note (1) With regard to parts of high voltage circuits and refrigeration cycle, judge it according to ordinary inspection methods.
(b) Instruction of how to replace indoor control PCB
Read the "SAFETY PRECAUTIONS" carefully first of all and then strictly follow it during the replacement in order to protect yourself.
The precautionary items mentioned below are distinguished into two levels, WARNING and CAUTION.
Both mentions the important items to protect your health and safety so strictly follow them by any means.
WARNING
Wrong installation would cause serious consequences such as injuries or death.
CAUTION
Wrong installation might cause serious consequences depending on circumstances.
After completing the replacement, do commissioning to confirm there are no anomaly.
Replacement should be performed by the specialist.
If you replace the PCB by yourself, it may lead to serious trouble such as electric shock or fire.
Replace the PCB correctly according to these instructions.
Improper replacement may cause electric shock or fire.
Shut off the power before electrical wiring work.
Replacement during the applying the current would cause the electric shock, unit failure or improper running.
It would cause the damage of connected equipment such as fan motor,etc.
Fasten the wiring to the terminal securely, and hold the cable securely so as not to apply unexpected stress on the terminal.
Loose connections or hold could result in abnormal heat generation or fire.
Check the connection of wiring to PCB correctly before turning on the power, after replacement.
Defectiveness of replacement may cause electric shock or fire.
In connecting connector onto the PCB, connect not to deform the PCB. It may cause breakage or malfunction.
Insert connecter securely, and hook stopper. It may cause fire or improper running.
Bundle the cables together so as not to be pinched or be tensioned. It may cause malfunction or electric shock for disconnection or deformation.
Memorized error log
• Higher priority error is memorized.
• Not memorized.
Confirmation of
remote control and
LEDs on the PCB of
indoor unit (Indoor/
outdoor unit, remote
control)
SAFETY PRECAUTIONS
WARNING
CAUTION
218
-
• Stop the unit by pressing the ON/OFF
switch of remote control.
• If the unit has recovered from anomaly, it
can be operated.
Check of the anomalous
operation data on the
remote control
-
'18 • SCM-T-251
Reset
Replacement/
Inspection repair of
of the unit/ faulty part,
remote control test run,
adjustment