73
100
10
-20 -10 0 10 20 30
Temperature in °C
6
8
20
40
60
80
200
Resistance
in kΩ
Fig. 36
Sensor type: NTC 10 k
Ω
2.
Test the resistance of the outside temperature sen-
sor across terminals "X3.1" and "X3.2" on the dis-
connected plug and compare it with the curve.
3.
Where actual values deviate severely from the
curve values, disconnect the wires at the sensor
and repeat test on the sensor itself.
4.
Depending on the result, replace the lead or the
outside temperature sensor.
Checking the boiler water temperature sensor, cylinder temperature sensor or flow temperature
sensor for the low loss header
%
A
X3
Fig. 37
1.
■
Boiler water temperature sensor: Disconnect
leads from boiler water temperature sensor
A
and check the resistance.
■
Cylinder temperature sensor: Disconnect plug
%
from the cable harness at the control unit and
check the resistance.
■
Flow temperature sensor: Disconnect plug "X3"
from the control unit and check the resistance
across terminals "X3.4" and "X3.5".
Troubleshooting
Maintenance
(cont.)
5686 293 GB
Diagnosis
