Buderus Logano plus GB402 Installation And Maintenance Instructions Manual page 60

10
Troubleshooting
Display Fault
1)
Type code code
V 4Y 523
V 4U 524
V 4A 575
B 5L 542
Tab. 21 Fault displays
1) V = interlocking; B = blocking
60
Cause Description
Boiler Temperature too
temperature low at the boiler
sensor break. temperature
sensor
(< -5 °C)
Boiler sensor The boiler sensor
short circuit. detected an
excessively high
temperature
(> 130 °C).
Intelligent high The boiler flow
limit safety temperature has
cut-out reached its
responds. maximum
permissible level.
Incomplete The MC10
communication generates this fault
with the SAFe. if not all required
data is supplied by
the SAFe.
Test procedure/cause
Check the sensor lead.
Check the plug-in
connection.
Check sensor values
according to table.
Check the voltage at the
temperature sensor
according to table (SAFe
documentation).
Check the sensor lead.
Check the plug-in
connection.
Check sensor values
according to table.
Check the voltage at the
temperature sensor
according to table (SAFe
documentation).
The high limit safety cut-out
has responded.
Check the cabling between
the SAFe and the MC10.
Logano plus GB402 - Subject to technical modifications!
Action
Replace in case of
damage.
Clean or replace if
contaminated.
Replace in case of
damage.
Refit plug it is found to
be loose.
Replace the
temperature sensor in
case of deviations.
Replace the SAFe in
case of deviations.
Replace in case of
damage.
Clean or replace if
contaminated.
Replace in case of
damage.
Refit plug it is found to
be loose.
Replace the
temperature sensor in
case of deviations.
Replace the SAFe in
case of deviations.
Check gas valve.
(Does the flame
extinguish after a control
shutdown?)
Replace the SAFe if the
connections are OK.