Bosch Worcester Greenstar 8000 Series Installation And Maintenance Instructions Manual page 68

Fault finding and diagnosis
Fault text on the display, description
306 V Flame signal after closing the fuel supply
815 B Low loss header temp. sensor faulty
1017 W Water pressure too low
1022 B Hot water storage temperature sensor is
defective
1065 B Pressure sensor defective or not connected 1. Connect the plug to the pressure sensor correctly.
1068 W Outside temperature sensor defective
1075 W Short circuit of the temperature sensor at
the heating block
1076 W No signal from the temperature sensor at
the heating block available
2920 V Fault in flame monitoring
2927 B Flame failed during burner operation
2946 V Incorrect code plug detected
2948 B No flame signal with low output
2950 B No flame signal following starting procedure The burner starts automatically after cleaning.
2963 B Signal from flow and heat exchanger
temperature sensor outside the permissible
range
2964 B Flow rate in heat exchanger too low
2965 B Flow temperature too high
2966 B Flow temperature rise in heat exchanger too
rapid
2967 B Flow/ heate exchanger temperature sensor
differential too great
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Remedy
1. Replace the air/gas ratio control valve.
2. Replace the ionisation cable.
3. Replace the control unit/burner control unit.
1. Check the sensor port.
2. Check the differential sensor for incorrect installation position or breakage.
1. Top up water and vent the system.
2. Replace the pressure sensor.
1. Connect the plug to the hot water temperature sensor correctly.
2. Mount the hot water temperature sensor correctly.
3. Replace the hot water temperature sensor.
4. Replace the connecting lead to the hot water temperature sensor.
2. Replace the connecting lead to the pressure sensor.
3. Replace the pressure sensor.
4. Replace the control unit.
Check the connecting lead.
1. Replace the temperature sensor.
2. Replace the connecting lead to the temperature sensor.
3. Replace the control appliance.
1. Replace the temperature sensor.
2. Replace the connecting lead to the temperature sensor.
3. Replace the control unit.
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1. Open the main shut-off valve.
2. Open the appliance shut-off valve.
3. Shut down the appliance and check the gas line.
4. Signal evaluation on printed circuit board defective.
5. Replace the ionisation electrode.
6. Establish protective conductor connection (PE) in the control unit.
7. Replace the ignition cable.
8. Replace the connecting lead to the ionisation electrode.
9. Replace the air/gas ratio control valve.
10.Set the burner correctly.
11.Set the burner at minimum rated load.
12.Convert the flue system.
13.The interconnected room air supply is too small or the size of the ventilation
opening is too small.
14.Clean the heating block on the flue gas side.
15.Replace the control unit/burner control unit.
Replace the coding plug.
The burner starts automatically after cleaning.
1. If the fault occurs repeatedly: check the settings of the CO2 values.
1. Set the correct gas/air ratio correctly.
Connect the connecting lead correctly.
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Greenstar 8000 Style – 6720883855 (2019/01)