10
Troubleshooting
Logano plus GB402 - Subject to technical modifications!
57
10.2.2 Fault displays
OL
-
Opening the gas
valve.
-
-
-
OF
-
Insufficient boiler
flow rate.
Temperature differential
between the flow and
return > 15 K.
Temperature differential
between flow and safety
temperature sensor
> 15 K.
Check the flow
temperature on the
BC10, check the
return temperature
with RC35 or the
service key, measure
the resistance of the
boiler sensor (high
limit safety cut-out)
and compare with the
curve.
Adjust the setting of the
boiler circuit pump.
Check the surface
temperature of the cast
section that is equipped
with the safety
temperature sensor using
a thermometer.
Check whether a cast
section is blocked with
dirt.
Display
code
Supple-
mentary
code
Cause
Description
Test procedure/
cause
Action
Tab. 20 Operating codes
Type
1)
Display
code
Fault
code
Cause
Description
Test procedure/cause
Action
B
2E
207
Water
pressure
< 0.6 bar.
-
Check whether the heating
system pressure is at least
1 bar.
Correct the operating
pressure.
V
2U
533
Incorrect
hydraulic
connection of
boiler or
pump.
The boiler control
unit has
recognised an
incorrect flow on
the water side.
Check that the boiler flow
and return have not been
swapped.
Check pump for correct
flow direction.
Connect flow and return
correctly.
Ensure correct pump
flow direction.
B
2U
565
Excessive
differential
between the
flow and
return
temperature.
> 40 K
Heat exchanger
protection due to
excessive
temperature
spread.
Problems with the
hydraulics.
Check the system
hydraulics.
V
2U
575
Intelligent high
limit safety
cut-out, flow.
The actual boiler
flow temperature
reaches the
intelligent high limit
safety temperature
for the flow of
140 °C, and a
flame current is
detected or the
solenoid valves are
open.
Check the flow rate on the
water side.
Ensure adequate flow
rate.
Replace boiler sensor/
high limit safety cut-out.
Replace ignition/
monitoring electrode.
Tab. 21 Fault displays
1) V = interlocking; B = blocking
