Buderus Logano plus GB402 Installation And Maintenance Instructions Manual page 58

10
Troubleshooting
Display Fault
1)
Type code code
V 3C 537
V 3C 538
V 3C 540
V 4A 520
Tab. 21 Fault displays
1) V = interlocking; B = blocking
58
Cause Description
No speed. The SAFe receives
no speed
feedback, although
the fan is
supposed to be
running.
Fan speed too The detected
low. speed is lower
than the specified
speed.
Excessively The detected
high fan speed is higher
speed. than the specified
speed.
Intelligent high The flow
limit safety temperature has
cut-out, flow. reached a value of
100 °C.
Test procedure/cause
Check cabling between the
SAFe and the fan for
contact separation, breaks
and damage.
Check plug-in connection
at the SAFe and the fan.
Fan contaminated.
Fan faulty.
Check PWM signal/SAFe
cabling for contact
separation, breaks and
damage.
Check plug-in connections
for damage.
The temperature rise is
monitored by the boiler
sensor. Consequently the
burner is switched off in
good time, making an
occurrence of this fault
message under normal
circumstances unlikely.
Unfavourable hydraulics in
two-boiler systems: boilers
influence each other, e.g.
via the return or flow.
Logano plus GB402 - Subject to technical modifications!
Action
Make the contacts
correctly. Replace cable
if required.
If power is available (no
an start), replace fan.
Clean fan if required.
Replace fan.
Make the contacts
correctly. Replace cable
if required.
Replace fan.
Check hydraulics.