Buderus GB402-320-5, Installation And Maintenance Instructions For Contractors

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11 Troubleshooting
Logano plus GB402 – 6 720 820 700 (2018/01) 52
B 8L 534 No gas pressure
or additional flue
gas pressure
limiter (pressure
> 7.5 bar) has
responded. There is no gas
pressure although
solenoid valve 1 should
have opened. The
burner makes three
successive attempts at
starting, then it waits
for one hour before
making three more
start attempts. Check that the gas isolator is
open. Replace the gas valve if
required.
Check whether there is gas
pressure. Check the gas pressure.
Check whether the flue gas
pressure limiter has responded. Reset the flue gas pressure
limiter.
Check the flue gas path for
blockages.
Check electrode. Replace electrode if required.
Check ignition transformer. Replace ignition transformer if
required.
Check gas filter for
contamination. Replace gas filter if required.
V 8P 580 Solenoid valve 1
leaking The valve test system
has detected an
unacceptably high
leakage rate on
solenoid valve 1. Check the gas valve for
contamination.
Gas filter fitted.
Replace the gas valve.
V 8U 581 Solenoid valve 2
leaking The valve test system
has detected an
unacceptably high
leakage rate on
solenoid valve 2. Check the gas valve for
contamination.
Gas filter fitted.
Replace the gas valve.
V 9Y 500
501
502
503
Internal SAFe
relay faulty. Internal SAFe
electronics faulty. Press "Reset" and wait to see if
the fault has been removed. Replace the SAFe if the fault
persists after "Reset" has been
pressed.
V CY 566 Return
temperature
< -5 °C
(interruption)
The control unit
receives unrealistic
values from the return
sensor. Check cabling between SAFe and
return sensor.
Check electrical connection of the
SAFe cable.
Replace cable if required.
Remedy contact problem if
required.
Replace temperature sensor if
required.
Check the resistance values of the
temperature sensor against the
table.
Check voltage at the temperature
sensor terminals inside the SAFe
according to table.
Replace SAFe if resistance
values of the temperature
sensor are correct, but voltage
values are incorrect.
V CY 567 Return
temperature
> 130 °C (short
circuit)
The control unit
receives unrealistic
values from the return
sensor. Check cabling between SAFe and
return sensor. Replace cable if required.
Check electrical connection of the
SAFe cable. Remedy contact problem if
required.
Check the resistance values of the
temperature sensor against the
table. Replace temperature sensor if
required.
Check voltage at the temperature
sensor terminals inside the SAFe
according to table. Replace SAFe if resistance
values of the temperature
sensor are correct, but voltage
values are incorrect.
V CO 568 Water pressure
sensor fault
(cable break). Water pressure sensor
interruption (voltage >
3.5 V). Check lead to water pressure
sensor.
Check water pressure sensor.
Eliminate any interruption.
Replace water pressure
sensor.
V CO 569 Water pressure
sensor fault
(short circuit). Water pressure sensor
short circuit (voltage <
0.5 V). Check lead to water pressure
sensor. Remedy any short circuit.
Check water pressure sensor. Replace water pressure
sensor.
Type
1)
Display code Fault Code Reason Description: Test procedure/cause Corrective measure
Table 23 Fault displays
1) V = locking; B = blocking