Viessmann Vitotronic 300 Installation And Service Instructions Manual page 42

Troubleshooting
Fault Codes
(continued)
Displayed System characteristics
fault code
80 Burner control unit in a fault
state; system cools down; burner
control unit locked out.
81 Burner control unit in a fault
state.
82 Burner control unit in a fault
state; system cools down; burner
control unit locked out.
83 Burner control unit in a fault
state.
88 Burner control unit in a fault
state.
89 Burner control unit in a fault
state.
90 Control mode
91 Control mode
92 No solar DHW heating.
93 Control mode.
94 No solar DHW heating.
98 Control mode
42
Vitotronic 300, GW5B Installation and Service
Cause
Short circuit, boiler water
temperature sensor, burner
control unit.
Sensor drift, boiler water
temperature sensor, burner
control unit.
Short circuit, flue gas
temperature sensor (A or B),
burner control unit.
Sensor drift, flue gas temperature
sensor (A or B), burner control
unit.
Lead break, boiler water
temperature sensor, burner
control unit.
Lead break, flue gas temperature
sensor
(A or B), burner control unit.
Short circuit, temperature sensor
/ connection at solar control
module.
Short circuit, temperature sensor
aÖ, connection at solar control
module.
Short circuit, collector
temperature sensor, connection
of temperature sensor & at solar
control module or sensor at S1
of the Vitosolic.
Short circuit, temperature sensor,
connection to S3 of the Vitosolic.
Short circuit, DHW tank
temperature sensor, connection
of temperature sensor % at solar
control module or sensor at S2 of
the Vitosolic.
Lead break, temperature sensor
/, connection at solar control
module.
Measures
Check lead and dual sensor;
replace sensor if required.
Check lead and dual sensor;
replace sensor if required.
Check lead and sensors (A and
B), replace sensor if required.
Check lead and sensors (A and
B), replace sensor if required.
Check lead and dual sensor;
replace sensor if required.
Check lead and sensors (A and
B), replace sensor if required.
Check temperature sensor /
(see separate installation and
service instructions).
Check temperature sensor aÖ
(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 sensor at the solar control
unit (see separate installation and
service instructions).
Check temperature sensor /
(see separate installation and
service instructions).
Check coding address "20" in
the "Solar" group.