Checking The Flue Gas Temperature Sensor - Viessmann Vitodens 222-F Installation And Service Instructions For Contractors

Maintenance
(cont.)
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 59 Sensor type: NTC 10 k
1. ■ Boiler water temperature sensor
Disconnect leads from boiler water temperature
sensor and check resistance.
A
■ Cylinder temperature sensor
Disconnect plug
%
control unit and check the resistance.
Flow temperature sensor
■
Disconnect plug "X3" at the control unit and
check the resistance across terminals "X3.4" and
"X3.5".

Checking the flue gas temperature sensor

The flue gas temperature sensor locks out the boiler if
the permissible flue gas temperature is exceeded.
After the flue system has cooled down, press reset
button R to cancel the lock.
Fig. 60
Ω
from the cable harness at the
2. Check the sensor resistance and compare it with
the curve.
3. In the event of severe deviation replace the sensor.
Danger
The boiler water temperature sensor is
directly immersed in the heating water (risk
of scalding).
Drain the boiler on the heating water side
before replacing the sensor.
20
10
8
6
4
2
1
0.8
0.6
0.4
10 30 50 70 90 110
Temperature in °C
Fig. 61 Sensor type: NTC 10 k
1. Disconnect leads from flue gas temperature sensor
.
A
2. Check sensor resistance and compare it to the
curve.
3. In the event of severe deviation replace the sensor.
Troubleshooting
Ω
99