Viessmann MatriX Service Instructions For Contractors page 28

Troubleshooting
Fault codes
(cont.)
Displayed fault System characteristics
code
F F4 No flame formation during the
safety time, no signal cap-
tured by the ionisation flame
monitor
F F4 No flame formation during the
safety time, no signal cap-
tured by the ionisation flame
monitor
F F5 No air pressure captured by
air pressure switch 1, fan idle
F F5 Air pressure switch 1
switches off during operation
F F6 No gas pressure captured by
gas pressure switch
F F7 Fan pressure is created dur-
ing the idle state check of air
pressure switch 1
F F7 Contact of air pressure switch
1 not in idle state
F F8 Flame extinguishes during
operation
F F8 Flame extinguishes during
operation
F F8 Flame extinguishes during
operation
F F9 Fan not running, fan speed
not reached
F F9 Status duration too long, fan
ramp-up
F F9 Varying fan speed
F F9 No fan feedback
F FA Fan runs without demand,
burner control unit in a fault
state
F FB Excessive combustion cham-
ber pressure, burner control
unit in a fault state
28
Cause
Gas train does not open
Combustion characteris-
tics not ideal
Air pressure switch 1 faul-
ty, incorrectly connected
or incorrectly set
Flue gas back pressure,
condensate banked up, air
pressure switch 1 hose
faulty, connecting hose
leaking
Gas shut-off valve closed,
gas pressure switch faulty,
multiple problems with gas
supply
Wind influence on fan
Air pressure switch 1 faul-
ty
Incorrect gas type selec-
ted
Burner gauze assembly
faulty
Combustion characteris-
tics not ideal
Fan faulty, cables are faul-
ty or broken
Internal fault, fan cannot
reach its set value
Fan faulty, cable " a-Ö A"
faulty or broken
Fan faulty, external fan
power supply not connec-
ted or faulty, cable " A"
a-Ö
faulty or broken, fan
blocked (possibly by for-
eign bodies)
Fan does not reach idle
state, cable " A" faulty,
a-Ö
fan faulty, burner control
unit faulty
Flue gas path or conden-
sate path blocked off
Measures
Check connecting cable, check
gas train and replace if required
Adjust the burner (see from
page 11; if necessary also adjust
the setting screws with the burner
in idle mode to facilitate the burner
start)
Replace air pressure switch 1, con-
nect or adjust correctly
Remove flue gas back pressure,
check if condensate banked up, re-
set burner control unit, replace
hose
Open gas shut-off valve, check gas
flow pressure, replace gas filter if
required, reset burner control unit,
replace gas train
Check flue outlet (chimney)
Replace air pressure switch 1
Adjust gas type setting (see
page 7)
Check burner gauze assembly, re-
place if damaged
Adjust burner setting (see from
page 11)
Check cables, replace fan if re-
quired
Replace fan or burner control unit
Check cable, possibly replace ca-
ble " A" or fan
a-Ö
Check cable " A", check exter-
a-Ö
nal power supply, replace cable or
fan, remove foreign bodies
Fan subject to wind influence,
check flue outlet and fan, replace
cable " A", replace fan, replace
a-Ö
burner control unit
Check flue gas path or condensate
path and clean if required