Viessmann MatriX Service Instructions For Contractors page 37

Fault codes
(cont.)
Displayed fault System characteristics
code
F F1 Burner control unit in a fault
state; system cools down
F F2 Burner control unit in a fault
state; system cools down
F F3 Ionisation flame monitor re-
ports faulty flame signal dur-
ing start-up or after the post-
purge.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
F F4 No flame formation during
safety time; ionisation flame
monitor reports no flame sig-
nal.
F F4 Poor start-up characteristics;
rotary damper does not
close.
F F4 No flame formation during
safety time, no signal repor-
ted by the ionisation flame
monitor.
F F4 No flame formation during
safety time, no signal repor-
ted by the ionisation flame
monitor.
F F5 Air pressure switch not re-
porting any air pressure. Fan
not running.
Cause
Flue gas excess tempera-
ture; excessive gas
throughput
No water in boiler; mini-
mum pressure too low
Excessive boiler tempera-
ture
Gas train not gas-tight
(gas is escaping and burn-
ing); incorrect coding card.
Ionisation electrode incor-
rectly adjusted, ionisation
electrode not plugged in,
earth fault of electrode or
cable
Ignition electrodes incor-
rectly adjusted, electrode
earth fault, ignition unit
faulty, burner control unit
faulty
Insulation body of ignition
or ionisation electrode
cracked
Servomotor faulty, servo-
motor connecting cable
faulty, output relay faulty
(burner control unit)
Gas train does not open.
Combustion characteris-
tics not ideal
Air pressure switch faulty,
incorrectly connected or
incorrectly set
Troubleshooting
Measures
Wait until temperature falls below
the permissible flue gas tempera-
ture. Reset the burner control unit.
Check water level; check heat ex-
changer surfaces for contamina-
tion; check CO setting; set gas
2
throughput according to rated boil-
er heating output (see supply val-
ues in the Specification table).
Check flue gas collector for dam-
age and leaks; check temperature
sensor (flue gas high limit safety
cut-out).
Wait until temperature falls below
the permissible boiler water tem-
perature. Reset the burner control
unit.
Check ionisation path; replace cod-
ing card; replace gas train.
Insert plug of ionisation electrode;
check cable; adjust ionisation elec-
trode (see page 24)
Adjust ignition electrodes (see
page 24); replace ignition unit; re-
place burner control unit.
Replace ignition or ionisation elec-
trode.
Replace connecting cable; replace
servomotor; replace burner control
unit.
Check connecting cable; check
gas train and replace if necessary.
Adjust the burner; if necessary also
adjust the setting screws when the
burner is idle, in order to facilitate
the burner start.
Replace air pressure switch, con-
nect or set correctly.
37