Phenomenon Observed After Short-Circuit, Wire Breakage On Sensor; Checking The Indoor Electrical Equipment - Mitsubishi Heavy Industries SRK15ZTL-W Service Manual

(8) Phenomenon observed after short-circuit, wire breakage on sensor

(a) Indoor unit
Operation
Sensor
mode
Cooling
Room air temperature
sensor
Heating
Heat exchanger
Cooling
temperature
sensor
Heating
Cooling
Humidity sensor
Heating
■ Humidity sensor operation
Failure mode
①
②
①②
① ②
-
(b) Outdoor unit
Operation
Sensor
mode
Cooling
Heat exchanger
temperature sensor
Heating
Cooling
Ourdoor air
temperature sensor
Heating
Discharge pipe
All modes
temperature sensor

(9) Checking the indoor electrical equipment

(a) Indoor unit PCB check procedure
Is there voltage between terminal
blocks ① and ② ? (AC 220/230/240
V)
YES
Is the fuse burnt out? (3.15 A)
NO
Is the voltage between terminal
blocks ② and ③ oscillating between
DC 0 and 20V?
YES
Indoor electrical components
are normal.
Short-circuit
Freezing cycle system protection trips and stops the compressor.
Control input circuit resding
Short-circuit
Compressor stop.
Defrost operation is not performed.
The compressor cannot pick up its speed owing to the current
safe so that the designed capacity is not achieved.
The compressor cannot pick up its speed owing to the heating
overload protection so that the designed capacity is not achieved.
NO
Inspect power source
for outdoor unit.
YES
Replace fuse.
NO
Replace indoor unit
PCB.
Phenomenon
Air-conditioning system operation
Phenomenon
Defrost operation is performed for 10 minutes at approx. 35 minutes.
Defrost operation is performed for 10 minutes at approx. 35 minutes.
37
- -
'22 • SRK-SM-349
Disconnected wire
'09•SRK-DB-087D
'09•SRK-DB-087D
Disconnected wire