Viessmann Vitodens 333 Service Instructions Manual page 81

Repairs
(cont.)
% Plug for the cylinder primary tem-
perature sensor
&
1. Boiler water temperature sen-
sor
Pull the leads off the boiler tem-
perature sensor and check the
resistance.
&
Cylinder primary temperature
sensor
Pull the plug % from the cable
harness on the control unit and
measure the resistance.
&
Flow temperature sensor
Pull plug "X3" off the control unit
and measure the resistance
across terminals "X3.4" and
"X3.5".
2. Check the sensor resistance and
compare the actual values with the
curve.
3. Replace the sensor in cases of
severe deviation.
Danger
The boiler water tempera-
ture sensor is immersed in
the heating water (risk of
scalding).
Drain the boiler before
replacing the sensor.
Troubleshooting
81