Viessmann Vitotronic 300 Installation And Service Instructions Manual page 47

Vitotronic 300, GW5B Installation and Service
Fault Codes
(continued)
Displayed System characteristics
fault code
F0 Operation according to internal
burner control unit defaults.
F1 Burner control unit in a fault
state; system cools down.
F2 Burner control unit in a fault
state; system cools down.
F3 Ionization flame monitor reports
faulty flame signal during start-up
or after the post-purge.
F4 No flame formation during safety
time; ionization flame monitor
reports no flame signal.
No flame formation during safety
time; ionization flame monitor
reports no flame signal.
No flame formation during safety
time; ionization flame monitor
reports no flame signal.
Poor start-up characteristics;
rotary damper does not close.
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Flame does not build during the
safety time, no signal captured
by the ionization flame monitor.
Cause
Communication fault, burner
control unit.
Flue gas excess temperature;
excessive gas throughput.
Excessive boiler water
temperature.
Gas valve not gas tight (gas is
escaping and burning);
incorrect coding card.
Ionization electrode incorrectly
adjusted; ionization electrode not
plugged in. Earth leakage of
electrode or cable.
Ignition electrodes incorrectly
adjusted, electrodes earthed,
faulty ignition unit, faulty burner
control unit.
Insulation body of ignition or
ionization electrode cracked.
Servomotor faulty, servomotor
connecting cable faulty, output
relay faulty (burner control unit).
Incorrect gas type selected.
Gas valve does not open.
Combustion characteristics not
ideal.
Troubleshooting
Measures
Check plug and KM BUS
to burner control unit.
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
setting; set gas throughput
according to rated heating output
of boiler (for connection values,
see boiler service instructions).
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 boiler service
instructions)
Adjust ignition electrodes
(see boiler service instructions);
replace ignition unit; replace
burner control unit.
Replace ignition or ionization
electrode
Replace connecting cable;
replace servomotor; replace
burner control unit.
Select gas type (see boiler
service instructions).
Check connecting cable; check
gas valve and replace if required.
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).
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