Technical data

Vitotronic 300, GW5B & MW1B Installation and Service
5693 973 - 05
56
Fault Codes
Troubleshooting, Vitotronic 300-K
Displayed
fault code
System characteristics Cause Measures
10 Activates at 32 °F (0° C)
outside temperature.
Short circuit, outside temperature
sensor
Check outside temperature
sensor (see page 110).
18 Activates at 32 °F (0° C)
outside temperature.
Lead break, outside temperature
sensor
Check outside temperature
sensor (see page 110).
20 Stand-alone control unit without
supply temperature sensor (poss.
supply temperature not high
enough).
Short circuit, common supply
temperature sensor
Check supply temperature sensor
(see page 110).
28 Stand-alone control unit without
supply temperature sensor (poss.
supply temperature not high
enough).
Lead break, common supply
temperature sensor
Check supply temperature sensor
(see page 110).
40 Mixing valve is closed. Short circuit, supply temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2)
Check supply temperature sensor
(see page 110).
44 Mixing valve is closed. Short circuit, supply temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3)
Check supply temperature sensor
(see page 110).
48 Mixing valve is closed. Lead break, supply temperature
sensor, heating circuit with mixing
valve M2 (heating circuit 2)
Check supply temperature sensor
(see page 110).
4C Mixing valve is closed. Lead break, supply temperature
sensor, heating circuit with mixing
valve M3 (heating circuit 3)
Check supply temperature sensor
(see page 110).
50 DHW tank primary pump “ON”:
Set DHW temperature = set
supply temperature
Priority control is cancelled.
or
With primary store system:
DHW tank heating is started
and stopped by DHW tank
temperature sensor 2.
Short circuit, DHW tank
temperature sensor 1
Check the DHW tank
temperature sensor
(see page 110).
51 With primary store system:
DHW tank heating is started
and stopped by DHW tank
temperature sensor 1.
Short circuit, DHW tank
temperature sensor 2
Check the DHW tank
temperature sensor
(see page 110).
58 DHW tank primary pump “ON”:
Set DHW temperature = set
supply temperature
Priority control is cancelled.
or
With primary store system:
DHW tank heating is started
and stopped by DHW tank
temperature sensor 2.
Lead break, DHW tank temperature
sensor 1
Check the DHW tank temperature
sensor (see page 110).
59 With primary store system:
DHW tank heating is started
and stopped by DHW tank
temperature sensor 1.
Lead break, DHW tank temperature
sensor 2
Check the DHW tank
temperature sensor
(see page 110).