Viessmann VITOLIGNO 300-P Service Instructions Manual page 90

Troubleshooting
Fault display
Displayed System characteris-
fault code tics
94 Solar circuit pump
switched off; no cylin-
der heating through
the solar thermal sys-
tem.
Collector frost protec-
tion function starts, if
enabled and if
required
9A Solar circuit pump
switched off; no cylin-
der heating through
the solar thermal sys-
tem.
Collector frost protec-
tion function starts, if
enabled and if
required
9B Solar circuit pump
switched off; no cylin-
der heating through
the solar thermal sys-
tem.
Collector frost protec-
tion function starts, if
enabled and if
required
9C Solar circuit pump
switched off; no cylin-
der heating through
the solar thermal sys-
tem.
Collector frost protec-
tion function starts, if
enabled and if
required
90
(cont.)
Cause
Short circuit, cylin-
der temperature
sensor
External Vitosolic
solar control unit:
Connection to S2
Lead break, collec-
tor temperature
sensor
External Vitosolic
solar control unit:
Connection to S1
Lead break, tem-
perature sensor
External Vitosolic
solar control unit:
Connection to S3
Lead break, cylin-
der temperature
sensor
External Vitosolic
solar control unit:
Connection to S2
Measures
Check the cylinder tem-
perature sensor (see
page 96)
Check collector tempera-
ture sensor (see
page 96)
Check temperature sen-
sor (see page 96)
Check the cylinder tem-
perature sensor (see
page 96)