Troubleshooting 6 - Indoor Unit Error Method: Heat Exchanger Middle Sensor Error - Fujitsu Airstage V series Service Manual

Trouble shooting 6
INDOOR UNIT Error Method:
Heat Exchanger Middle Sensor Error
Detective Actuators:
Indoor Unit Controller PCB Circuit
Heat Exchanger Middle Thermistor
Forecast of Cause : 1. Connector defective connection 2. Thermistor defective 3. Controller PCB defective
Check Point 1 : Check connection of Connector
p Check if connector is loose or removed
p Check erroneous connection
p Check if thermistor cable is open
>>Reset Power when reinstalling due to removed connector or incorrect wiring.
OK
Check Point 2 : Remove connector and check Thermistor resistance value
Thermistor Characteristics (Rough value)
Temperature (°C)
Resistance Value ( )
Temperature (°C)
Resistance Value ( )
If Thermistor is either open or shorted, replace it and reset the power.
OK
Check Point 3 : Check voltage of Controller PCB (DC5.0V)
Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)
Duct Schematic Diagram (Connector connection)
If the voltage does not appear, replace Controller PCB and reset the original address.
Indicate or Display:
Indoor Unit : Operation LED 3 Times Blink, Timer LED Flash
Outdoor Unit : LED1 Flash, LED6
ERROR CODE : E : 0A
Detective details:
When open or shorted Heat Exchanger middle Thermisor is detected at Power
ON.
0 5 10
176.0 134.2 103.3
40 45 50
25.6 20.8 17.1
H/E Inlet Thermistor
(CN20 Wire:Black)
H/E Middle Thermistor
(CN20 Wire:Gray)
Room Temp. Thermistor
(CN19 Wire:Black)
Swing LED 2 Times Blink
1Time Blink
15 20 25
80.3 62.9 49.7
Small size Wall mount Schematic Diagram(Directsoldering to PCB)
06-14
30 35
39.6 31.7
DC
Room Temp. Thermistor
(CN6 Wire:Black)
H/E Inlet Thermistor
(CN13 Wire:Black)
H/E Middle Thermistor
(CN7 Wire:Gray)