
69
Checking the boiler water temperature sensor or the cylinder
temperature sensor
5
1.
■ Boiler water temperature sensor:
Pull the leads from boiler water
temperature sensor
A
and check
the resistance.
■ Cylinder temperature sensor: Pull
plug
%
from the cable harness at
the control unit and check the
resistance.
10
1
10 30 50 70 90 110
Temperature in °C
0.4
0.6
0.8
2
4
6
8
20
Resistance in kΩ
2.
Check the sensor resistance and
compare the actual values with the
curve.
3.
Replace the sensor in case of severe
deviation.
Danger
The boiler water temperature
sensor is immersed in the
heating water (risk of scald-
ing).
Drain the boiler before replac-
ing the sensor.
Troubleshooting
Repairs
(cont.)
5692 774 GB