Troubleshooting Diagnostics - Viessmann Vitogas 100 Service Instructions Manual

Troubleshooting
Diagnostics
Fault
Boiler will not
start
Burner control
unit enters a
fault state
16
Cause
No voltage
Boiler water
temperature too high
High limit safety
cut−out has tripped
Flue gas monitoring
equipment (if
installed) has shut
system down
Strapping plug aNS
is missing in burner
control unit
Strapping plug aYA is
missing in burner
control unit
No gas available
Ignition burner will
not start
Mains cable
incorrectly connected
Ionisation current
too low or
cable break
Remedy
Check fuse and connections of main
power supply. Check switches on
control unit for their settings.
Wait until boiler water temperature
has fallen by approx. 20 K
Press reset button on control unit
Wait approx. 17 minutes. If boiler
then starts automatically, check flue
pipe and chimney.
If boiler does not start automatically,
check flue gas monitoring equipment
(see page 15).
Fit strapping plug aNS or a flue gas
monitoring sensor
Fit strapping plug aYA
Air in gas supply pipe. Press reset
button on burner control unit to
repeat start procedure
Check ignition electrode.
Check gas supply.
Interchange cores L 1 and N of mains
power cable
Check ionisation current (minimum
value 5 mA with main burner
operating).
Remove ignition burner and check for
damage.
Check polarity of mains power supply
cable.
Control unit faults
Service instructions
Boiler control unit