Diagnosis - Viessmann Vitodens 100-W B1HA 26Vitodens 100-W B1HA 35Vitodens 100-W B1KA 35 Installation And Service Instructions Manual

Vitodens 100-W, B1HA series & B1KA Combi Installation/Service

Diagnosis

Sequence of operation and potential faults during each start-up cycle
Control unit issues a heat
demand
yes
Fan starts
yes
Ignition
yes
Gas valve opens
yes
Ionization current builds
(higher than 2 
A Symbol
A)
yes
Burner in operation
display
no
After approx. 1 min, fault 9
no
Fault F4
no
Fault F4
no
Fault F4
no
Stops below the set boiler
no
water temperature and
restarts immediately
Fault display
In case of a fault, the display will show
code.
If flashes and "R" appears, the burner is locked.
See page 39.
For an explanation of the fault codes, see the following
table.
Troubleshooting
action
Increase set value and
ensure heat is drawn off
Check the fan, fan
connecting cables, power
at the fan and fan control
Check the ignition module
connection
Check the gas valve (120V
control voltage) and gas
supply pressure
Check electrode adjustment
and gas line for air locks
Check the flue system
for tightness (flue gas
recirculation); check the
gas flow pressure
and the fault
55