Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 174

SCM-HG (4 room)
(4) Phenomenon observed after shortcircuit, wire breakage on thermistors, etc.
(a) Indoor unit
Operation
Sensor
mode
Cooling
Room temperature
thermistor
Heating
Cooling
Heat exchanger
thermistor
Heating
(b) Outdoor unit
Operation
Thermistor
mode
Cooling
Heat exchanger
pipe thermistor
Heating
Cooling
Outdoor temperature
thermistor
Heating
Discharge pipe
All modes
thermistor
Transformer All modes
Shunt resistance All modes
(5) How to make sure of remote controller
(1)
Is remote
controller
normal?
YES
Again pushing
operating switch
YES
Operating the unit?
NO
Does backup
switch operates?
YES
Operating the unit.
NO
Control problem on
main unit
172
Shortcircuit
Release of continuous compressor operation command
Continuous compressor operation command is not released.
System can be operated normally.
High pressure control mode (Inverter stop command)
Shortcircuit
Defrosting is not performed.
Defrosting is not operated.
Compressor overload protection is disabled.
(Can be operated.)
Current cut does not function. (Backed up with 20A fuse.)
NO
Remote controller
defects
Abnormality is not
found.
Replace the display.
Is the unit
operable with remote
controller?
NO
Defective remote
controller
Phenomenon
Continuous compressor operation command is not released.
Release of continuous compressor operation command
Continuous compressor operation command is not released.
(Anti-frosting)
Hot keep (Indoor fan stop)
Phenomenon
System can be operated normally.
Defrosting is performed for 10 minutes at approx. 1 hour.
System can be operated normally.
Defrosting is performed for 10 minutes at intervals of approx. 30 minutes.
Compressor stop (There is no inverter output.)
Can be operated. Current safe does not function.
(Backed up with 25A a fuse.)
Can be operated but current cut does not function.
Note (1) How to check the remote controllre
(a) Press the reset switch of the remote controller.
(b) If all LCD are displayed after zero (0) display, it is
basically normal.
YES
Normal
Broken wire
Broken wire