Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 89

Anormality of thermistor
Is connection to connector
good?
Yes
Is thermistor resistance
value normal?
Yes
Replace PCB.
(4) Trouble Diagnostic Procedures
Unit malfunctions or
does not stop.
Indoor lamp of
indoor unit does not
illuminate.
Outdoor fan does not
operate.
Disconnection of thermistor and defective connection of connector
No
Repair connector.
No
Replace thermistor.
Runaway of micro-
computer
Check receptacle voltage.
Check if PCB fuse is blown.
Check varistor.
No
Check transformer secondary
voltage
(32, 40 model only)
Replace PCB.
Check it during cooling
operation.
Yes
Check voltage with fan
connector.
No
(1)
Operates
Remove 52XΒ(52X6)red
wires to check operation.
Does not operate.
(1)
Operates
Short-circuit 63H to check
operation.
Does not operate.
(1)
Measure voltage of 52XB
(52X6) No.2 ,and terminal
block 2.
Chart for thermistor temperature
resistance characteristics
(Disconnection)
(kΩ)
(Short circuit)
Remove receptacle.
No change.
Insert it after 3 min.
and operate.
Normal operation.
Replace fuse.
Replace varistor.
Replace transformer
Check capacitor.
Normal
Replace fan motor.
Replace 23DH.
Replace 63H.
No
Replace 52XB(52X6).
SRK-H
Temperature (°C)
Replace PCB.
Microcomputer rarely
mis-starts even during
times or power supply
or power failure, but, it
can sometimes occur
during those times. If it
occurs, check the opera-
tion, when the result is
positive then proceed as
normal.
Abnormal
Replace capacitor.
Notes (1) It is not necessary to inspect
the dedicated cooling unit.
(2) Value in ( ) indicates
32,40models
87