Diagnostics Table: Faults With Fault Display On Control Unit - Viessmann VITODENS 100-W WB1B Series Installation And Service Instructions Manual

Diagnosis
(continued)
Fig. 67

Diagnostics table: Faults with fault display on control unit

Fault message in System behavior*
display window
Start-up and Maintenance
10 Constant mode
18 Constant mode
30 Burner blocked
38 Burner blocked
50 No DHW heating or
external heat
demand
58 No DHW heating or
external heat
demand
Start-up and Maintenance
Burner in fault mode
a9
Burner blocked
b0
Burner blocked
b8
e5 Burner blocked
f0 Burner blocked
f1 Burner in fault mode
Burner in fault mode
f2
Burner in fault mode
f3
1
Constant mode: Boiler operates based on "tr" temperature setting
*
Burner blocked: If fault cause is corrected, burner resumes operation.
Burner in fault mode: Boiler control requires manual reset before burner can resume operation.
1
Cause
Outside temperature sensor
shorted out
Outside temperature sensor
wire broken
Boiler water temperature sensor
shorted out
Boiler water temperature sensor
lead broken
Number % connection / lead
shorted.
Number % connection / lead
open / broken.
Communication error Open
Therm controller.
Flue gas temperature sensor
shorted out
Flue gas temperature sensor
lead broken
Internal fault
Internal fault
Maximum flue gas temperature
exceeded (110º C / 230º F).
Fixed high limit tripped
Flame signal is already present
at burner start
Troubleshooting
Faults are indicated by a flashing fault
code with fault code symbol "U" on
the display.
For fault code explanations see the
following table.
Corrective measures
Check the optional outside
temperature sensor and wiring
(see page 68).
Check the outside temperature sensor and
leads (see page 68).
Check the boiler water temperature sensor
(see page 67).
Check the boiler water temperature sensor
(see page 67).
Check the % connection
(see wiring diagram on page 38).
Check the % connection
(see wiring diagram on page 38).
Turn boiler OFF, then ON.
Check connections and wire;
replace Open Therm controller if required.
Check the sensor (see page 70).
Check the sensor (see page 70).
Check the ionization electrode and cables
(see page 57). Reset control.
Replace the control unit.
Check the flue gas system
(see page 70). Reset control.
Check the heating system water level.
Check the circulation pump operation.
Vent the heating system of air. Check the
fixed high limit and wiring. Reset control.
Check the ionization electrode and
connecting cable. Reset control.
65