Lead Break, Outside Temperature Sensor - Viessmann VITOTRONIC 300 Installation And Service Instructions Manual

Troubleshooting
Fault messages
(cont.)

18 Lead break, outside temperature sensor

Regulates as if the outside temperature were 0 °C.
Cause
Lead break, outside temperature sensor
19 Wireless outside temperature sensor
Regulates as if the outside temperature were 0 °C.
Cause
Lead break/communication failure, wireless outside
temperature sensor
20 Short circuit, flow temperature sensor
Standalone control unit without flow temperature sen-
sor (flow temperature possibly not high enough)
Cause
Short circuit, common flow temperature sensor
28 Lead break, flow temperature sensor
Standalone control unit without flow temperature sen-
sor (poss. flow temperature not high enough)
Cause
Lead break, common flow temperature sensor
30 Short circuit, boiler water temperature sensor
■ With DHW cylinder:
Circulation pump for cylinder heating on, boiler is
maintained at set cylinder temperature.
Cause
Short circuit, boiler water temperature sensor
38 Lead break, boiler water temperature sensor
■ With DHW cylinder:
Circulation pump for cylinder heating on, boiler is
maintained at set cylinder temperature.
118
Measure
Check outside temperature sensor: See chapter "Check
temperature sensors"
Measure
Check wireless connection. Place the wireless outside
temperature sensor close to the boiler. Forget outside
temperature sensor, then pair again (see separate
documents). Replace wireless outside temperature sen-
sor.
Measure
Check flow temperature sensor: See chapter "Check
temperature sensors"
Measure
Check flow temperature sensor: See chapter "Check
temperature sensors"
■ Without DHW cylinder:
Boiler is regulated by the temperature controller.
Measure
Check the boiler water temperature sensor: See chap-
ter "Checking temperature sensors"
■ Without DHW cylinder:
Boiler is regulated by the temperature controller.