Checking The Boiler Temperature Sensor And Fixed High Limit, Dhw Tank Temperature Sensor Or Flow Temperature Sensor For The Low Loss Header; Check The Flue Gas Temperature Sensor - Viessmann Vitodens 200-W Service Instructions Manual

Vitodens 200-W B2HA 80, 100 Service
Corrective Action
Checking the boiler temperature sensor and fixed high
limit, DHW tank temperature sensor or flow temperature
sensor for the low loss header
1. Boiler temperature sensor:
Remove lead to boiler water temperature sensor §
or fixed high limit §A and check the resistance.
DHW Tank temperature sensor:
Pull plug % from the cable harness at the control
unit and check the resistance.
Supply temperature sensor or Low-loss header
temperature sensor ?:
Pull plug "X3" from the control unit and check the
resistance across terminals "X3.4" and "X3.5".
Note: Only one temperature sensor ? may be used.
2. Check the sensor resistance and compare the actual
values with the curve.
3. Replace the sensor in the case of severe deviation.
Sensor type: NTC 10 kΩ
WARNING
The boiler temperature sensor is immersed in the heating
water (risk of scalding). Drain the boiler before replacing
the sensor.
Check flue gas temperature sensor
When exceeding the maximum permissible flue gas
temperature value, the flue gas temperature sensor locks
the appliance. Unlock the appliance by pressing reset
button R. after the vent system has cooled down.
1. Remove cables from flue gas temperature sensor A.
2. Check the sensor resistance and compare the actual
values with the curve in the chart.
3. Replace sensor in case of severe deviation.
Temperature sensors
Troubleshooting
79