Viessmann VITOTRONIC300 Installation And Service Instructions Manual page 71

Vitotronic 300, GW2B Installation and Service
Fault Display
(continued)
Displayed System characteristics
fault code
59 With primary store system:
DHW tank heating is started and
stopped by DHW tank temperature
sensor 1.
5A Control mode.
60 Boiler with maximum temperature,
no output reduction, mixing valve
return temperature control "Open".
68 Boiler with maximum temperature,
no output reduction, mixing valve
return temperature control "Open".
70 Shunt pump constantly "ON".
With primary store system:
Mixing valve primary circuit
"Closed", no DHW heating.
78 Shunt pump constantly "ON".
With primary store system:
Mixing valve primary circuit
"Closed", no DHW heating.
90 Control mode.
91 Control mode.
Cause
Lead break, DHW tank
temperature sensor 2
Lead break, low
loss header supply
temperature sensor
Short circuit, temperature
sensor aJA
Lead break, temperature
sensor aJA
Short circuit, temperature
sensor aJB
Lead break, temperature
sensor aJB
Short circuit, temperature
sensor /,
Connection at the solar
control module.
Short circuit, temperature
sensor aÖ,
Connection at the solar
control module.
Troubleshooting
Measures
Check the DHW tank temperature
sensor (see page 124).
Check the supply temperature sensor
(see page 124).
Without supply temperature sensor:
Set code "52:0" in the "General" group.
Check temperature sensor aJA
(see page 124).
Check temperature sensor aJA
(see page 124).
Without temperature sensor:
Set code "4A:0" in the
"General" group.
Check temperature sensor aJB
(see page 124).
Check temperature sensor aJB
(see page 124).
Without temperature sensor:
Set code "4b:0" in the
"General" group.
Check temperature sensor /
(see separate installation and service
instructions).
Check temperature sensor aÖ
(see separate installation and service
instructions).
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