6 Operating tests Thermo Pro 90
602
6.4 Checking individual components
6.4.1 Resistance test of coolant temperature
sensor
During an electrical test with a digital multimeter, the tem-
perature sensor is to have the following values:
Resistance at 25 °C: 990 to 1,010 ohms
Test current: < 1 mA
6.4.2 Resistance test of glow plug
During an electrical test with a digital multimeter, the glow
plug is to have the following values:
6.4.3 Resistance test of exhaust temperature
sensor
During an electrical test with a digital multimeter, the
exhaust temperature sensor is to have the following values:
Resistance at 25 °C: 2,195 ± 4 ohms
Test current: < 5 mA
6.4.4 Testing combustion air fan
The test of the combustion air fan speed must be carried out
in the permissible operating voltage range. Check that the
fan is not rubbing during operation.
NOTE
The test of the combustion air fan is only carried out when
installed. This means the control unit must be mounted on
the fan housing. The reason for this is sensors in the control
unit which are required for speed control.
The test is carried out with the related Webasto Thermo Test
PC Diagnosis.
Speed specification is 6,100 rpm
Fig. 601 CO
2
adjustment value (permissible from 10.5 to 14.1 vol. %)
Altitude [m above sea level]
CO
2
adjustment value [vol. %] according to respective geodetic altitude or according to air pressure present
Glow plug: 12 V (red) 24 V (green)
Resistance at
25 °C: 270 ± 35 mohms 770 ± 100 mohms
Measuring accuracy better than ± 5 mohms according to
4-conductor measuring principle
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