Error 1075 W

Safety first:

- If you smell gas, do not touch the boiler. Evacuate the property and call your gas emergency number immediately.

- Before opening the boiler or touching electrical parts, isolate the mains electrical supply to the boiler and, if you are going to do any work, turn off the gas supply. Only qualified persons should work on gas or main-voltage electrical parts.

- If you are not confident working around gas/electrics, stop and call a Gas Safe engineer.

Initial homeowner checks (safe, non-invasive):

1) Try a controlled reset: follow the boiler manual procedure (usually press and hold reset/spanner for 3 seconds). If the fault clears and does not return, monitor for a while. If it reappears, do not keep resetting.

2) Check for obvious signs: inspect around the boiler for water leaks, corrosion, burnt wires, or condensation near the heating block. Moisture can cause sensor shorting.

3) Check the boiler’s information menu/cause code: on Worcester boilers you can press the spanner/return to view the cause code which can give more detail; note any secondary cause numbers.

4) Look for visible wiring/connectors from outside the casing (only visual): make sure external leads are seated and not obviously damaged.

If you are comfortable with basic electrical checks and have the right tools (multimeter) and have isolated power:

5) Remove the boiler cover only if you are competent. Locate the temperature sensor on or in the heating block/heat exchanger and the connector. Take photos before disconnecting so you can reassemble correctly.

6) With the sensor disconnected and the boiler still isolated from mains, measure the sensor resistance with a multimeter. Typical NTC sensors are in the kilo-ohm range at room temperature; a shorted sensor will read very low resistance (near zero ohms) and an open sensor will read very high/infinite. A short reading confirms the short-circuit fault. Note: exact resistance values vary by sensor type — check part documentation if available.

7) Inspect the wiring harness from the sensor to the PCB for chafing, pinched wires or signs of shorting; check the connector pins for corrosion, bent pins or water ingress. If the wiring is damaged, repair or replacement of the loom is required.

8) If the sensor reads as shorted or wiring is damaged, the next step is to replace the sensor and/or repair the wiring. Fit the correct Worcester replacement sensor for your model — do not fit improvised parts. Reassemble, restore power and test. If the fault clears, run the boiler and observe for recurrence.

When to call a professional:

- If the sensor measures shorted or open, if wiring or connector damage is present, or if you do not have the skills/tools to do the checks safely, call a Gas Safe registered engineer. They will correctly replace the sensor, check for underlying causes (water leaks, heat exchanger issues, PCB faults) and perform safe testing and commissioning.

- If you replace the sensor and the fault remains, the control board or heat control module (HCM) may be defective and will need professional diagnosis and replacement.

Important cautions:

- Do not repeatedly reset the boiler more than once or twice — persistent faults indicate a real safety issue.

- Do not attempt gas valve, burner or PCB repairs unless you are a Gas Safe qualified engineer.

- Always use genuine or approved replacement parts and have any safety-critical repairs signed off by a qualified engineer.

Summary: basic visual checks and a meter check of the sensor are reasonable DIY diagnostics if you are competent and have isolated power, but replacement of the sensor, wiring repairs, or any further investigation should be carried out by a Gas Safe engineer for safety and compliance.