Error 1076 W

Safety first: before doing anything switch the boiler off at the programmer and at the mains isolator. If you need to remove the boiler cover or access internal wiring switch the mains off at the consumer unit and confirm the boiler is dead. If you are not confident working around electrical equipment or gas appliances stop and call a Gas Safe engineer.

Initial homeowner checks:

1. Note exactly what the display shows including any flashing triangle or cause code. On a blocking error you can press the spanner/return button to view a three-digit cause code – record it.

2. Try a simple reset: follow the Greenstar 8000 reset procedure (press and hold the reset button or the required control for about 3 seconds, or follow the knob-reset method your manual describes). If the fault clears and does not return, monitor the boiler for recurrence. If it returns immediately or within a short time proceed to further checks.

3. Look for obvious signs at the boiler exterior: evidence of water leaks, corrosion, burn marks around connectors, or a damaged cable entering the boiler. Also check system pressure is within normal range (typically around 1–1.5 bar) and that external controls/stat thermostats are calling for heat when you expect them to.

Basic visual and non-intrusive checks (only with mains OFF if opening the case):

1. If you are competent and have isolated the mains, remove the outer cover and visually inspect the heating block area and the connector for the flow sensor. Check the sensor plug is fully seated and that the cable is not damaged or trapped.

2. Look for water ingress, green/white corrosion, or signs of overheating at the connector and wiring. Gently reseat the connector if it appears loose.

3. Refit the cover, restore power and try restarting the boiler. If reseating fixed a poor connection the error may not return.

If the fault persists call a qualified engineer. Typical professional diagnostic and repair steps they will perform:

1. With the boiler isolated and using correct access procedures the engineer will remove the sensor connector and measure the NTC resistance with a multimeter. Many Worcester flow/primary NTCs are approximately 10 kohm at 25°C but values vary by sensor and should be compared to the manufacturer specification. An open circuit (infinite resistance) or a short (very low resistance) confirms a sensor or wiring fault.

2. The engineer will check continuity of the sensor wiring between the sensor plug and the control board, and test for shorts to earth or to other conductors. They will inspect and test the control board/HCM input for the sensor circuit to determine whether the board is receiving the signal or has a fault.

3. If the sensor or cable is faulty they will replace the sensor or repair/replace the lead and then clear the fault and test the boiler under demand. If wiring and sensor test good but no signal reaches the control, the HCM/control unit (or connectors on the PCB) may be faulty and require replacement or repair.

4. After repair the engineer will reset the boiler and run the appliance to confirm correct operation and that the cause code does not return.

Important final points: do not attempt to bypass or run the boiler with a known sensor failure; this could defeat safety controls. Do not attempt to replace internal components such as the PCB, HCM, or gas/ignition parts yourself unless you are a Gas Safe registered engineer. When you call for service give the engineer the exact fault code (1076 W), any cause code shown, what you have tried (resets, reseating connectors), and whether the fault is intermittent or constant. This speeds diagnosis and helps ensure a safe, correct repair.