Buderus LOGANO PLUS GB312 Installation Instructions Manual page 58

10
Troubleshooting
Display
1)
Type code Fault code
K 7A 551
K 8L 579
L 8Y 590
Table 22 Fault messages
1) V = locking; B = inhibiting; BC = operating code
58
Cause Description
Power failure. There has been a brief
loss of power.
No gas pressure. There is no gas pressure.
( Section 10.3,
page 62 ff.)
Pressure switch in safety Break in pressure switch
assembly has tripped. safety assembly during
burner operation.
Testing sequence/
Cause Measure
Check power supply lead Rectify any contact
for loose contacts. problems.
Check wiring and proper
contact of power plug on
MC10/SAFe.
Check that the gas cock is Turn on gas cock if
turned on. necessary.
Check that gas pressure is Measure gas pressure.
present.
Check setting of low Correct low pressure
pressure switch (available switch (available
separately). separately) settings.
Check continuity on SAFe If there is no continuity
pressure switch, air on SAFe pressure
supply pressure switch, switch:
flue gas pressure switch
• Check whether
and high gas pressure
manual gas cock
switch (available
before Venturi is
separately)
open.
• Check connector on
gas valve is properly
seated.
• Replace pressure
switch.
If no continuity on
pressure/air supply
pressure/flue gas
pressure/high gas
pressure switch:
Replace pressure switch
concerned.
Replace low gas
If continuity OK on SAFe,
pressure switch and
air supply pressure, flue
wiring.
gas pressure and high gas
pressure switch
Check whether low gas Measure the gas
pressure switch (available pressure at 100 % boiler
separately) is breaking modulation.
circuit during operation.
Check if the air supply Check low gas pressure
switch or flue gas switch (available
pressure switch opens separately) setting.
while the boiler is
operating.
Check whether SAFe or Check flue/air supply
high gas pressure switch pipe for blockages.
(available separately) is
Replacing the
breaking circuit during
gas valve
operation
Section 10.3, page 87 ff
Logano plus GB312 – 6 720 647 367 (2012/11)