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Part 4 - Diagnosis and T
roubleshooting
4.18.4 Procedure
PH
T4 temperature sensor connection on
main PCB is loose
1
T4 temperature sensor has
short-circuited or failed
2
Replace main PCB
No
No
Yes
Yes
Ensure the sensor is connected properly
Replace the sensor
Notes:
1. For 30kW and 60kW units, temperature detection is port CN1 on the main PCB (labeled 10 in in Figure 4-2.1 in Part 4, 2.2 “Main PCB”) .
2. Measure sensor resistance. If the resistance is too low, the sensor has short-circuited. If the resistance is not consistent with the sensor’s resistance
characteristics table, the sensor has failed. Refer to Table 5-5.1 in Part 5, 5.1 “Temperature Sensor Resistance Characteristics”.