Viessmann Vitodens 100 Series Installation And Service Instructions Manual page 68

Troubleshooting
Fault display
Displayed System character-
fault code istics
F18 Continuous opera-
tion
F30 Burner locked out
F38 Burner locked out
F51 No DHW heating
F59 No DHW heating
F6F WLAN connection in-
terrupted
F70 Function at the ex-
ternal extension faul-
ty
68
(cont.)
Cause
Lead break, out-
side temperature
sensor or room
temperature sen-
sor
Short circuit, boiler
water temperature
sensor
Lead break, boiler
water temperature
sensor
Short circuit, cylin-
der temperature
sensor (gas con-
densing system
boiler) or outlet
temperature sen-
sor (gas condens-
ing combi boiler)
Lead break, cylin-
der temperature
sensor (gas con-
densing system
boiler) or outlet
temperature sen-
sor (gas condens-
ing combi boiler)
Communication
between control
unit and WLAN
module interrupted
Short circuit, col-
lector temperature
sensor S1 at the
external extension
Measures
Check the sensor (see
page 72).
Check the boiler water
temperature sensor (see
page 73).
Check the boiler water
temperature sensor (see
page 73).
Check the sensor (see
page 74).
Check the sensor (see
page 74).
Check connecting cable
between control unit and
WLAN module.
Check setting of parame-
ter P06 and P07.
Checking the sensor
Installation and
service instruc-
tions for external
extension