Viessmann Vitocrossal 300 Service Manual page 84

Troubleshooting
Fault Codes
(continued)
Fault code on display
EE
EF
F0
F1
F2
F3
*1 Control mode:
Burner in fault mode: Boiler control requires manual reset before burner can resume operation.
Burner blocked:
84
System behavior*1
Burner in a fault mode
Burner in a fault mode
Burner blocked
Burner in a fault mode
Burner in fault mode
Burner in fault mode
Boiler/burner fully operational (fault code must be verified and reset).
If fault cause is corrected, burner resumes operation.
Vitocrossal 300 CU3A 26 to 57 Service
Cause
At burner start, flame
signal is missing or too
weak
Flame is lost immediately
after it has built (during
the safety time)
Internal fault
Maximum flue gas
temperature exceeded
230ºF (110ºC) limit.
Fixed high limit switch
open (activated)
Flame signal already
present at burner start
Corrective action
Check gas supply (gas pressure
and gas regulator). Check gas
train. Check ionization electrode
and connecting cable.
Check ignition:
- Connecting leads to ignition
module and ignition electrode.
- Ignition electrode gap and
contamination (see page 20).
Check condensate drain.
Press reset button R.
Check gas supply (gas pressure
and gas regulator). Check flue
gas/ventilation air system for
flue gas recirculation. Check
ionization electrode (replace
if required):
- Distance to burner gauze
assembly (see page 20).
- Contamination of electrode
Press reset button R.
Replace the control unit.
Check heating system fill level.
Bleed air from system. Check
circulation pump. Check boiler
water temperature sensor and
cable. Press reset button R after
vent system has cooled down.
Check heating system fill
level. Check the circulation
pump. Bleed air from the
system. Check fixed high limit
switch and connecting cables.
Press reset button R.
Check the ionization electrode
and connecting cable.
Press reset button R.