Test; Check Ntc - Bosch WAT28400 Repair Instructions

Test

5.1

Check NTC

Prerequisite:
NTC has been removed.
5.1.1 Check NTC at room temperature
1. Measure temperature of the ambient air.
2. Operating range 0–99 °C
3. Measure resistance value of the NTC at room temperature.
4. 0 measurement of the resistance is approx. 0 Ω
► replace NTC. (Page 69)
5. 0 measurement of the resistance is infinite
► replace NTC. (Page 69)
6.
In the circuit diagrams select resistance setpoint values which
are near the room temperature.
Compare measured value of the resistance with the setpoint values of the
circuit diagrams.
7. 0 the measured value of the resistance deviates significantly from the
setpoint values
► replace NTC. (Page 69)
8. The measured value of the resistance corresponds to the setpoint values, see
circuit diagrams.
5.1.2 Check NTC as the temperature rises
Required tools:
? Heat source
1. Heat NTC.
2. Measure change in the resistance of the NTC as the temperature rises.
2017-05-22 / DIS 113_58300000186503_ara_en_c
3. 0 the measured value of the resistance does not drop as the temperature
rises
► replace NTC. (Page 69)
4. 0 the measured value of the resistance drops as the temperature rises
► Continue diagnosing the fault.
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