Viessmann B1KE Combi Series Installation And Service Instructions Manual page 73

Vitodens 100-W, B1HE/B1KE Combi Installation/Service
Fault Messages
Displayed System characteristics
fault code
F.62 Burner in a fault state
F.63 Burner in a fault state
F.67 Burner in a fault state
F.68 Burner in a fault state
F.69 Burner in a fault state
(continued)
Cause
High limit safety cut-
out has responded.
Flue gas temperature
limiter has responded.
Ionization current
lies outside the
permissible range
Flame signal is
already present at
burner start.
Ionization current
lies outside the
permissible range
Measures
Check heating system fill level.

Check pre-charge pressure in diaphragm expansion

tank. Adjust to required system pressure.
Check whether flow rate is sufficient (flow sensor

and circulation pump).
Check 3-way diverter valve function in actuator test.

Vent the system.
Reset the boiler.
Check heating system fill level.

Check pre-charge pressure in diaphragm expansion

tank. Adjust to required system pressure.
Check whether flow rate is sufficient (flow sensor

and circulation pump).
Check 3-way diverter valve function in actuator test.

Vent the system.
Reset the boiler once the flue system has cooled down.
Check gas supply (gas pressure and gas flow switch),
check gas solenoid valve and inlet strainer.
Check ionization electrode:
Clearance to flame body assembly.

Check electrode/flame body assembly for

contamination.
If specified measures don't help, replace fan unit.
Reset the boiler.
Close the gas shut-off valve. Remove connecting cable
of the ionization electrode. Reset the boiler.
If the fault persists, replace BCU burner control unit:
See page 89.
Check ionization electrode:
Check whether insulation block is touching electrode

ceramic.
Check gas solenoid valve: Activate "Minimum heating

output" for approx. 4 min in actuator test.
If this causes a fault to occur, replace BCU burner
control unit.
In the actuator test, switch from "Minimum heating

output" to "Maximum heating output". If this fault
occurs during modulation, check the intake screen
for contamination. Replace the fan unit if necessary.
Troubleshooting
73