Worcester Bosch Greenstar 8000 Series Boiler Error Codes

Including: All Variants

Error Code: Light off

Cause: No boiler demand Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: Light on

Cause: Heating demand on boiler is OK. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 1 flash 5 seconds off

Cause: No ionisation detected after ignition. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 2 flashes 5 seconds off

Cause: Loss of ionisation signal during operation. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 3 flashes 5 seconds off

Cause: Gas valve error. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes 5 seconds off

Cause: First safety timing error / ignition timing error. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 5 flashes 5 seconds off

Cause: Ionisation detected after burner stopped Gas valve EV2 leak test failed Gas valve EV1 leak test failed Ionisation current detected before burner start Gas valve error Ionisation sensor shorted Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes 5 second gap 1 long flash

Cause: Sensor test failed. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes, 5 second gap, 2 long flashes"

Cause: Safety temperature too high. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes, 5 second gap, 3 long flashes"

Cause: Max safety thermostat activated. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes, 5 second gap, 4 long flashes"

Cause: Return temperature too high. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 4 flashes, 5 second gap, 5 long flashes"

Cause: Flow temperature too high – supply sensor exceeded 110°c. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: long flash, 4 quick flashes, 5 second gap, 1 long flash, 4 quick flashes"

Cause: Heating control module (HCM) defective. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 2 long flashes, 4 quick flashes, 5 second gap, 2 long flashes, 4 quick flashes"

Cause: Fan running too fast Fan running too slow No airflow after defined period of time Fan not running Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 3 long flashes, 4 quick flashes, 5 second gap, 3 long flashes, 4 quick flashes"

Cause: Mains voltage interrupted after locking error. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.
Error Code: 5 long flashes, 4 quick flashes, 5 second gap, 5 long flash, 4 quick flashes."

Cause: All other miscellaneous faults. Difficulty: 1 2 3 4 5 Engineer: No Solutions To Try: Reset the boiler by turning the control knob anti-clockwise to the reset position.
Error Code: 4 long flashes, 4 quick flashes, 5 second gap, 4 long flash, 4 quick flashes"

Cause: Internal control board faults. Difficulty: 1 2 3 4 5 Engineer: Required Solutions To Try: Will require an engineer to run tests on your pump. It is not recommened you try and free it yourself.