Viessmann Vitocal 300-G Installation And Service Instructions Manual page 124

Troubleshooting
Control unit diagnostics
ID Message
(priority)
6B Ext. Heat
source ("U")
70 Room tem-
perature sen-
sor HK1 ("U")
71 Room tem-
perature sen-
sor HK2 ("U")
72 Room tem-
perature sen-
sor HK3 ("U")
73 Room tem-
perature sen-
sor NC ("U")
78 Room tem-
perature sen-
sor HK1 ("U")
79 Room tem-
perature sen-
sor HK2 ("U")
7A Room tem-
perature sen-
sor HK3 ("U")
124
(cont.)
1. Cause
2. Measures
1. Break, external heat source tem-
perature sensor
2. Check the sensor and replace, if
required
1. Short circuit, room temperature sen-
sor, heating circuit 1
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
1. Short circuit, room temperature sen-
sor, heating circuit 2
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
1. Short circuit, room temperature sen-
sor, heating circuit 3
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
1. Short circuit, room temperature sen-
sor NC
2. Check the sensor and replace, if
required
1. Break, room temperature sensor,
heating circuit 1
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
1. Break, room temperature sensor,
heating circuit 2
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
1. Break, room temperature sensor,
heating circuit 3
2. Check the sensor and replace, if
required
(see Vitotrol installation instructions)
Access
right
Customer
Customer
Customer
Customer
Customer
Customer
Customer
Customer