Viessmann B1HE-199 - Page 73

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Vitodens 100-W, B1HE/B1KE Combi Installation/Service
Fault Messages
(continued)
Troubleshooting
Displayed
fault code
System characteristics Cause Measures
F.62 Burner in a fault state High limit safety cut-
out has responded.
 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.
F.63 Burner in a fault state Flue gas temperature
limiter has responded.
 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.
F.67 Burner in a fault state Ionization current
lies outside the
permissible range
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.
F.68 Burner in a fault state Flame signal is
already present at
burner start.
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.
F.69 Burner in a fault state Ionization current
lies outside the
permissible range
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.