Viessmann Vitoflame 100 Service Instructions For Contractors page 31

Diagnosis
(cont.)
Fault Flash-
ing
code
red
Burner starts,
flame builds, but
the system shuts
down after a short
while (not a fault
shutdown)
Burner goes from 7 ×
operation into a
fault state, when
flame is already
established
7 ×
7 ×
7 ×
Flame extin- 7 ×
guishes during op-
eration
7 ×
Cause
Lack of gas
Ionisation current too
low (< 1.5 µA)
Electrode body faulty
Ionisation current too
low because of incor-
rect burner settings
Faulty earthing
Mixer assembly con-
taminated
Air damper incorrectly
positioned
Troubleshooting
Measures
Clean or replace gas
filter. Check the gas
pressure switch set-
tings. Check the gas
supply pressure.
Check the position and
condition of the sensor
electrode and modify
or replace the elec-
trode, if required
Measure ionisation
current and replace io-
nisation electrode or
earth electrode, if re-
quired
Correct burner settings
Check the earth con-
nection
Clean mixer assembly
Correct the switch cam
adjustment at the air
damper motor (see
page 8)
31