Troubleshooting; Diagnostics - Viessmann Vitogas 100 Service Instructions Manual

Diagnostics

Fault
The boiler will
not start
The burner
control unit
enters a fault
state
Cause
No voltage
Boiler water
temperature too high
The high limit safety
cut-out has tripped
The flue gas
monitoring
equipment (if
installed) has shut
the system down
Strapping plug aNS
is missing in the
burner control unit
Strapping plug aYA is
missing in the burner
control unit
No gas available
The ignition burner
will not start
Mains cable
incorrectly connected
Ionisation current too
low or
cable break
Remedy
Check the fuse and connections of
the main power supply. Check the
switches on the control unit for their
settings.
Wait until the boiler water temperature
has fallen by approx. 20 K
Press the reset button on the control
unit
Wait approx. 17 minutes. If the boiler
then starts automatically, check the
flue pipe and the chimney.
If the boiler does not start
automatically, check the flue gas
monitoring equipment (see page 16).
Fit strapping plug aNS or a flue gas
monitoring sensor
Fit strapping plug aYA
Air in the gas supply pipe. Press the
reset button on the burner control
unit to repeat the start procedure
Check the ignition electrode.
Check the gas supply.
Interchange cores L1 and N of the
mains power cable
Check the ionisation current
(minimum value 5 mA with the main
burner operating).
Remove the ignition burner and
check for damage.
Check the polarity of the mains
supply cable.
Control unit faults
Service instructions
Boiler control unit

Troubleshooting

17