Viessmann Vitoflame 100 Service Instructions Manual page 28

Troubleshooting
Diagnostics
(cont.)
Fault/ Flash−
characteristics ing
code
red
Burner does
not start;
demand
indicator does
not illuminate
Burner does
not start;
demand
indicator
illuminates
3 ×
28
Cause
No voltage present
High limit safety
cut−out activated
Vitoair motor faulty Replace the Vitoair motor
Fuse in the
soundness tester
blown
Fault during
soundness test
(fault indicator
illuminates)
Fuse in the plug−in
panel blown
Soundness tester
faulty
Gas supply
pressure too low;
gas pressure
limiter switches
OFF
Burner control unit
faulty
Burner motor faulty Replace burner motor
Servomotor faulty
(no voltage at
terminal "4")
Measure
Check the fuses in the control
unit and the connection panel;
check the electrical
connections, the position of the
ON/OFF switch at the control
unit and at the mains isolator
Press the reset button at the
boiler control unit
Replace fuse
Check the gas pressure test
port at the gas combination
valve for soundness.
Replace the gas combination
valve in case the valves are not
sound.
Replace fuse
Replace the soundness tester
Check the gas supply pressure.
The gas supply pressure
should be at least 20 mbar.
Clean the gas filter, if required.
Replace the burner control unit
Replace servomotor