Viessmann Vitotronic 300 Installation And Service Instructions Manual page 43

Vitotronic 300, GW5B Installation and Service
Fault Codes
(continued)
Displayed System characteristics
fault code
99 Control mode
9A No solar DHW heating.
9B Control mode
9C No solar DHW heating.
9E Control mode
9F Control mode
A0 Boiler cools down.
A1 Boiler cools down.
A2 Boiler cools down.
A3 Boiler cools down.
A7 Control mode as per
delivered condition.
Cause
Lead break, temperature sensor
aÖ, connection at solar control
module.
Lead break, collector temperature
sensor, connection of
temperature sensor & at solar
control module or sensor at S1 of
the Vitosolic.
Lead break, temperature sensor,
connection to S3 of the Vitosolic.
Lead break, DHW tank temperature
sensor, connection of
temperature sensor % at solar
control module or sensor at S2 of
the Vitosolic.
No supply rate in solar circuit or
flow rate too low, or temperature
limiter has responded.
Solar control module or Vitosolic
fault. Displayed if a fault occurs
at these devices that has no fault
code in the Vitotronic.
Fault, safety equipment at "X7"
of plug-in adaptor 2 for external
safety equipment.
Fault, safety equipment at "X3"
of plug-in adaptor 2 for external
safety equipment.
Fault, safety equipment at "X2"
of plug-in adaptor 2 for external
safety equipment.
Fault, safety equipment at "X1"
of plug-in adaptor 2 for external
safety equipment.
Faulty programming unit
Troubleshooting
Measures
Check temperature sensor aÖ
(see separate installation and
service instructions).
Check coding address "20" in
the "Solar" group.
Check sensor at the solar control
unit (see separate installation and
service instructions).
Check sensor at the solar control
unit (see separate installation and
service instructions).
Check sensor at the solar control
unit (see separate installation and
service instructions).
Check solar circuit (see
separate installation and service
instructions).
Check solar control unit
(see separate installation
and service instructions).
Check safety equipment and
reset if required.
Check safety equipment and
reset if required.
Check safety equipment and
reset if required.
Check safety equipment and
reset if required.
Replace the programming unit.
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