Repairs - Viessmann Vitodens 300 Service Instructions Manual

Checking and acknowledging faults
Displayed Const.
fault code
FF X

Repairs

Checking the outside temperature sensor (weather-compen-
sated control units)
Weat- System
her- character-
comp. istics
X Burner
blocked
1. Pull plug X3 from the control unit.
Troubleshooting
(cont.)
Cause Remedy
Internal fault Remove EMC
interference.
If the equip-
ment will not
restart, check
the boiler
coding card
and replace,
or replace the
control unit.
85