Buderus Logano plus GB402 Installation And Maintenance Instructions Manual page 63

Display Fault
1)
Type code code
B 7A 550
B 7A 551
B 7P 549
B 8L 534
V 8P 580
V 8U 581
Tab. 21 Fault displays
1) V = interlocking; B = blocking
Logano plus GB402 - Subject to technical modifications!
Cause Description
Undervoltage. The mains voltage
is too low.
Voltage There has been a
interruption. brief power failure.
The safety The continuity of
chain has the external
opened. components tied
into the MC10
safety chain has
been interrupted.
No gas There is no gas
pressure or pressure although
additional flue solenoid valve 1
gas pressure should have
limiter opened. The
(pressure burner makes three
> 7.5 bar) has successive
responded. attempts at
starting, then there
is a delay of one
hour, before
making three more
start attempts.
Solenoid valve The valve test
1 leaking. system has
detected an
unacceptably high
leakage rate on
solenoid valve 1.
Solenoid valve The valve test
2 leaking. system has
detected an
unacceptably high
leakage rate on
solenoid valve 2.
Test procedure/cause
The power supply must not
fall below 195 V.
Check the power cable for
possible loose contacts.
Check the wiring and
correct contacts of the
mains plug at the MC10 or
SAFe.
Check the continuity of the
components.
Check that the gas tap is
open.
Check whether there is gas
pressure.
Check whether the flue gas
pressure limiter has
responded.
Check electrode.
Check ignition transformer. Replace ignition
Check gas filter for
contamination.
Check gas valve for
contamination.
Gas filter fitted.
Check gas valve for
contamination.
Gas filter fitted.
10
Troubleshooting
Action
Ensure the correct
power supply.
Remedy any contact
problems.
If required, replace faulty
components.
Replace the gas valve if
required.
Check the gas pressure.
Reset the flue gas
pressure limiter.
Check the flue for
blockages.
Replace electrode if
required.
transformer if required.
Replace gas filter if
required.
Replace gas valve.
Replace gas valve.
63