Mitsubishi Heavy Industries SRK100VNXPZSX Technical Manual page 92

5) Phenomenon observed after shortcircuit, wire breakage on sensor
Operation
Sensor
mode
Cooling
Room temperature
sensor
Heating
Cooling
Heat exchanger
sensor
Heating
Cooling
Humidity sensor
Heating
■ Humidity sensor operation
Failure mode
(b) Outdoor unit
①
②
Operation
Sensor
mode
①②
Cooling
① ②
Heat exchanger
sensor
Heating
Cooling
Ourdoor air
temperature sensor
Heating
Discharge pipe
All modes
sensor
6) Checking the indoor electrical equipment
a) Indoor 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.
b) Indoor unit fan motor check procedure
i) Indoor PCB output check
i)
ii)
iii)
DC several V
(4-6 V)
CNU
Shortcircuit
Freezing cycle system protection trips and stops the compressor.
Control input circuit resding
Shortcircuit
NO
Inspect power source
for outdoor unit.
YES
Replace fuse.
NO
Replace indoor PCB.
(–)
GND
DC15V
⑥ ⑤ ④ ③
⑥ ⑤ ④ ③
Phenomenon
Air conditioning system operation
Phenomenon
Defrosting is performed for 10 minutes at approx. 35 minutes.
Defrosting is performed for 10 minutes at approx. 35 minutes.
DC 308-336V
Indoor PCB
② ①
91
- -
② ①
'17 • PAC-T-257
Disconnected wire
'09•SRK-DB-087D
Disconnected wire
① ④ ⑤
Measuring Voltage range when
point normal
① − ③
④ − ③
⑤ − ③
-
-