Viessmann VITOTRONIC 200 Installation And Service Instructions Manual page 69

Vitotronic 200 and 300-K Installation and Service
Fault Display Vitotronic 300-K
Fault codes
Displayed fault code System characteristics
10 Activates at 0° C outside
temperature
18 Activates at 0° C outside
temperature
20 Vitotronic 300-K regulates alone
without supply temperature sensor
(supply temperature may not be
high enough)
28 Vitotronic 300-K regulates alone
without supply temperature sensor
(supply temperature may not be
high enough)
40 Mixing valve is closed.
44 Mixing valve is closed.
48 Mixing valve is closed.
4C Mixing valve is closed.
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.
(continued)
Cause
Short circuit, outside
temperature sensor
Lead break, outside
temperature sensor
Short circuit, common
supply temperature sensor
Lead break, common supply
temperature sensor
Short circuit, supply
temperature sensor, heating
circuit with mixing valve
M2 (heating circuit 2)
Short circuit, supply
temperature sensor, heating
circuit with mixing valve
M3 (heating circuit 3)
Lead break, supply
temperature sensor, heating
circuit with mixing valve
M2 (heating circuit 2)
Lead break, supply
temperature sensor, heating
circuit with mixing valve
M3 (heating circuit 3)
Short circuit, DHW tank
temperature sensor 1
Troubleshooting
Measures
Check the outside
temperature sensor
(see page 87).
Check outside temperature
sensor (see page 87)
Check the common supply
temperature sensor
(see page 87)
Check the common supply
temperature sensor
(see page 87)
Check the supply
temperature sensor (see
page 87).
Check the supply
temperature sensor
(see page 87).
Check the supply
temperature sensor (see
page 87).
Check the supply
temperature sensor (see
page 87).
Check the DHW tank
temperature sensor
(see page 87).
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