51
5584 109 - 10
Vitocrossal 200 CM2 186 to 311 Service
Troubleshooting
Fault Codes
(continued)
Displayed
Fault Code
System Characteristics
Cause
Measures
F E5
Burner control unit in a fault
state
Internal fault of the burner
control unit and during test of
ionization input
Replace burner control unit
F EE
Burner control unit in a fault
state
Internal error in feedback from
gas safety valves; output relay
does not respond
Reset burner control unit; replace
burner control unit
F EF
Burner control unit in a fault
state
Internal error in feedback from
gas safety valves; output relay
does not respond
Reset burner control unit; replace
burner control unit
F F0
Emergency operation
according to internal
default
Communication error KM BUS
burner control unit
Check the KM BUS cable
plug for firm seating;
check all KM BUS cables
F F1
Burner control unit in a fault
state; system cools down
Flue gas excess temperature;
excessive gas throughput
Wait until temperature falls below
the permissible flue gas temperature.
Reset burner control unit. Check water
level; check heat exchanger surfaces
for contamination; check CO
2
setting;
set gas throughput according to rated
boiler heating output (see connection
values page 18).
F F2
Burner control unit in
a fault state; system
cools down
Excessive boiler
water temperature
Wait until temperature falls below the
permissible boiler water temperature;
reset burner control unit
F F3
Ionization flame monitor reports
faulty flame signal during start-
up or after the post-purge
Gas valve leaking (flame
present); incorrect coding card
Check ionization path; replace coding
card; replace gas valve
F F4
No flame formation during
safety time; ionization flame
monitor reports no flame signal
Ionization electrode incorrectly
adjusted; ionization electrode
not plugged in. Ground fault
of electrode or cable
Insert plug of ionization electrode;
check cables; adjust ionization
electrode (see page 19)
F F4
No flame formation during
safety time; ionization flame
monitor reports no flame signal
Ignition electrode not set
correctly; earth leakage of
electrodes; ignition unit faulty;
burner control unit faulty
Adjust ignition electrodes (see page 19);
replace ignition unit; replace burner
control unit
F F4
No flame formation during
safety time; ionization flame
monitor reports no flame signal
Insulation body of ignition or
ionization electrode cracked
Replace ignition or ionization electrode