Viessmann VITOTRONIC 100 Installation And Service Instructions Manual page 118

Troubleshooting
Faults which are displayed at the programming unit
Fault
System
code
characteristics
Control mode
c4
Boiler cools down
c8
c9
ca
cb
118
Cause
Communication
with function
extension 0−10 V
faulty
Error
Low water indicator
Fault
Maximum pressure
limiter
Fault
Minimum pressure
limiter or
maximum pressure
limiter 2
Fault
Additional high
limit safety cut−out,
temperature limiter
or flue gas damper
(cont.)
Remedy
Check connections
and cables/leads; if
required replace
function extension
(see page 133).
Without function
extension,
set code "9d : 0"
Check water level in
system,
reset low water
indicator
(see page 136)
Check system
pressure, reset
maximum
pressure limiter
(see page 136)
Check system
pressure; reset
minimum or
maximum pressure
limiter (see page 136)
Check system
temperature; reset
high limit safety
cut−out or flue gas
damper
(see page 136)