Bosch Condens 8300i W Installation And Maintenance Instructions Manual page 49

Fault text on the display, description
2920 V Fault in flame monitoring
2923- V Boiler electr. system fault
2926
2927 B Flame extinguished during burner operation 1. Open the main shut-off valve.
2928 V Internal fault
2931 V System fault boiler electronics / basic
controller
2940 V System fault burner control unit
2946 V Incorrect code plug detected
2948 B No flame signal with low output
2950 B No flame signal following starting procedure Burner starts automatically after purging.
2951 V Loss of flame too many times
2952 V Internal fault when testing the ionisation
signal
Condens 8300i W – 6721841533 (2022/12)
Remedy
Check control device, replace if necessary.
1. Check air/gas ratio control valve cabling.
2. Check air/gas ratio control valve.
If the fault persists following a reset, the control device or the air/gas ratio control valve is
faulty and must be replaced.
2. Open the device shut-off valve.
3. Interrupt the power supply of the appliance and check the gas line.
4. Carry out function check for ignition.
5. Carry out function check for ionisation.
6. Connect the plug for the ionisation and ignition sections correctly.
7. Establish protective conductor connection (PE) in the control device.
8. Check flame sense electrode, replace if necessary.
9. Check ignition electrode, replace if necessary.
10.Check ignition electrode connecting lead, replace if necessary.
11.Replace the connecting lead to the flame sense electrode.
12.Set the burner correctly/replace the burner nozzles.
13.Set the burner at minimum rated load.
14.Check air/gas ratio control valve, replace if necessary.
15.Check the flue system, repair if required.
16.The interconnected room air supply is too small or the size of the ventilation opening
is too small.
17.Clean the heating block on the flue gas side.
18.Check control device/burner control unit, replace if necessary.
1. Perform reset.
2. Replace control device/burner control unit.
1. Perform reset.
2. Replace control device/burner control unit.
1. Perform reset.
2. Replace control device/burner control unit.
Replace boiler identification module/coding plug (Bosch contact customer service).
Burner starts automatically after purging.
If this fault occurs frequently, check CO
Set gas/air ratio correctly.
1. Open the main shut-off valve.
2. Open the device shut-off valve.
3. Interrupt the power supply of the appliance and check the gas line.
4. Carry out function check for ionisation.
5. Connect the plug for the ionisation and ignition sections correctly.
6. Establish protective conductor connection (PE) in the control device.
7. Check flame sense electrode, replace if necessary.
8. Check ignition electrode, replace if necessary.
9. Check ignition electrode connecting lead, replace if necessary.
10.Check flame sense electrode connecting lead, replace if necessary.
11.Set the burner correctly/replace the burner nozzles.
12.Set the burner at minimum rated load.
13.Check air/gas ratio control valve, replace if necessary.
14.Check the flue system, repair if required.
15.The interconnected room air supply is too small or the size of the ventilation opening
is too small.
16.Clean the heating block on the flue gas side.
17.Check control device/burner control unit, replace if necessary.
1. Perform reset.
2. Replace control device/burner control unit.
setting.
2
Troubleshooting
49