Viessmann VITODENS 200-W WB2B Series Start-Up/Service Instructions page 59

Diagnostics
(continued)
Fault codes
(continued)
Fault code on display
F2
F3
F4
F8
F9
FA
FC
Fd
FE
FF
No fault code dis-
played
*1
Control mode: Boiler/burner fully operational (fault code must be verified and reset).
Burner in fault mode: Boiler control requires manual reset before burner can resume operation.
Burner blocked: If fault cause is corrected, burner resumes operation.
*1
System behavior
Burner in fault mode Fixed high limit switch
open (activated)
Burner in fault mode Flame signal already
present at burner start
Burner in fault mode No flame signal
Burner in fault mode Gas valve closes too late
Burner in fault mode Fan speed too low during
burner start
Burner in fault mode Fan not at standstill
Burner in fault mode Gas valve faulty or faulty
modulation valve control;
or vent system blocked
Burner in fault mode Burner control unit fault
Burner blocked or in Strong interference (EMC)
fault mode field nearby or faulty main
PCB.
Burner blocked or in Strong interference (EMC)
fault mode field nearby or faulty main
PCB.
Boiler/burner in Flow switch open
standstill
Cause
Check heating system fill
level. Check the circulation pump.
Bleed air from the system. Check fixed
high limit switch and connecting cables.
Press "
Check the ionization
electrode and connecting cable.
Press "
Check the ionization electrode and
cable, measure the ionization current,
check the gas pressure, check the gas
valve, ignition, ignition module, ignition
electrodes and the condensate drain.
Press "
Check the gas valve. Check both control
wiring/connections. Press
Check the fan, the fan cables and
power supply. Check the fan control.
Press
Check the fan, the fan connecting
cables and fan control. Check the fan
control. Press "
Check the gas valve. Check the vent
system.
Press "
Check ignition electrodes and
connecting cables. Check whether a
strong interference (EMC) field exists
near the equipment. Press
Replace control unit if fault persists
Restart the equipment.
Replace the control unit if the
equipment will not restart
Restart the equipment.
Replace the control unit if the
equipment will not restart
Check pump operation and flow switch
Troubleshooting
Corrective action
RESET"
RESET"
RESET"
RESET.
RESET
RESET"
RESET"
RESET.
59