Viessmann Vitocrossal 200 CM2 186 Service Instruction page 51

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