Mitsubishi SRK100VNXWPZSX, Service Manual

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66
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'20 • PAC-SM-351
(v) Phenomenon observed after short-circuit, wire breakage on sensor
Sensor
Operation
mode
Phenomenon
Short-circuit Disconnected wire
Room temperature
sensor
Cooling
Heating
Heat exchanger
temperature sensor
Cooling
Heating
Humidity sensor
Cooling
Heating
■
Humidity sensor operation
Failure mode Control input circuit resding Air-conditioning system operation
①
②
①②
①
②
Freezing cycle system protection trips and stops the compressor.
circuit
-
short-
'09•SRK-DB-087D
(vi) Checking the indoor electrical equipment
1) Indoor unit PCB check procedure
(b) Outdoor unit
Is there voltage between terminal
blocks
①
and
②
? (AC 220/230/240
V)
Indoor electrical components
are normal.
Is the voltage between terminal
blocks ② and ③ oscillating between
DC 0 and 20V?
Inspect power source
for outdoor unit.
Replace fuse.
Replace indoor unit PCB.
Is the fuse burnt out? (3.15 A)
NO
YES
YES
NO
YES
NO
2) Indoor fan motor check procedure
a) Indoor unit PCB output check
① ④ ⑤
b) Fan motor resistance check
⑥ ⑤ ④ ③ ② ①
⑥ ⑤ ④ ③ ② ①
FM
i
DC15V
Indoor unit PCB
DC 308-336V
DC several V
(4-6 V)
CNU
(–)
GND
Blue Yello
w
White Black Red
Sensor
Operation
mode
Phenomenon
Shortcircuit Disconnected wire
Heat exchanger
sensor
Cooling
Heating
Ourdoor air
temperature sensor
Cooling
Heating
Discharge pipe
sensor
All modes
Measuring point Resistance when normal
① − ③
−
④ − ③
−
Measuring
point Voltage range when
normal
① − ③
④ − ③
⑤ − ③
Defrosting is performed for 10 minutes at approx. 35 minutes.
Defrosting is performed for 10 minutes at approx. 35 minutes.
k
M
iii)
ii)
i)
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