Operating instructions

Faults are indicated by a flashing fault
code with fault symbol "U" on the dis-
play.
For fault code explanations see the
following table.
Fault code
on the dis-
play
System character-
istics
Cause Measures
10 Constant mode Outside tempera-
ture sensor
shorted out
Check the outside tem-
perature sensor and
lead (see page 37).
18 Constant mode Outside tempera-
ture sensor lead
broken
Check the outside tem-
perature sensor and
lead (see page 37).
30 Burner blocked Boiler water tem-
perature sensor
shorted out
Check the boiler water
temperature sensor (see
page 39).
38 Burner blocked Boiler water tem-
perature sensor
lead broken
Check the boiler water
temperature sensor (see
page 39).
50 No DHW heating Cylinder tempera-
ture sensor
shorted out
Check the sensor (see
page 40).
51 No DHW heating Outlet tempera-
ture sensor
shorted out
Check the sensor (see
page 42).
52 Burner blocked Throughput sen-
sor shorted out
Check connections and
lead; replace sensor if
required.
58 No DHW heating Cylinder tempera-
ture sensor lead
broken
Check the sensor (see
page 40).
59 No DHW heating Outlet tempera-
ture sensor lead
broken
Check the sensor (see
page 42).
Fault messages on the display
33
Troubleshooting
5354 802 GB
Service