184
5790 733 - 07
Vitocrossal 300 CA3 Series 2.5 to 6.0 Installation/Service
Burner Fault Codes
(continued)
Troubleshooting
Displayed
fault code
System characteristics
Cause
Measures
F1
Burner control unit in a fault
state; system cools down.
Secondary boiler water
temperature sensor exceeded
Wait until temperature falls
below the permissible boiler
water temperature. Reset burner
control unit. Verify boiler flow air
pockets.
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.
F3
Ionization flame monitor reports
faulty flame signal during start-
up or after the post-purge.
Gas valve not gas tight (gas is
escaping and burning);
incorrect coding card.
Check ionization path; replace
coding card; replace gas valve.
F4
No flame formation during safety
time; ionization flame monitor
reports no flame signal.
Ionization electrode incorrectly
adjusted; ionization electrode not
plugged in. Ground leakage of
electrode or cable.
Insert plug of ionization
electrode; check cables; adjust
ionization electrode (see boiler
service instructions)
No flame formation during safety
time; ionization flame monitor
reports no flame signal.
Ignition electrodes incorrectly
adjusted, electrodes grounded,
faulty ignition unit, faulty burner
control unit.
Adjust ignition electrodes (see
boiler service instructions);
replace ignition unit; replace
burner control unit.
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
Poor start-up characteristics;
rotary damper does not close.
Servomotor faulty, servomotor
connecting cable faulty, output
relay faulty (burner control unit).
Replace connecting cable;
replace servomotor; replace
burner control unit.
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Incorrect gas type selected.
Select gas type (see boiler
service instructions).
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Gas valve does not open.
Check connecting cable; check
gas valve and replace if required.
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Combustion characteristics not
ideal.
Adjust the burner (see boiler
service instructions); if
necessary also adjust the setting
screws when the burner is off to
be able to start the burner).
