Error 360 V

Safety precautions:

1) Do not attempt to work on gas valves, the burner, or internal wiring unless you are a qualified Gas Safe engineer. Incorrect repairs create fire, carbon monoxide and gas leak risks.

2) Isolate electrical power to the boiler before removing the outer casing if you must inspect components. If you are not confident, stop and call a Gas Safe engineer.

3) Do not repeatedly reset the boiler as a long-term workaround; this can mask a genuine fault and may cause further issues.

Initial homeowner checks (safe and simple):

1) Note the exact error code and any additional cause code shown on the display. Take a photo of the display and any flashing indicators.

2) Check whether any recent work, part replacements or upgrades were done to the boiler or controls (new thermostat, programmer, or service) — incompatible parts are a common cause.

3) Turn the boiler off at the isolator for 1 minute, then restore power and see if the fault clears. If it does clear but returns, do not ignore it.

4) Check external controls (room thermostat, wireless relay, smart controls) are communicating correctly. If you recently replaced a thermostat or controller, revert to the previous control or check its compatibility.

Basic inspection (only if comfortable and after isolating mains power):

1) Switch the boiler to the OFF position and isolate from the mains supply at the fused spur.

2) Remove the outer casing following the manual instructions (if provided) and look for the code plug / HCM location (this is usually on or near the control box). Do not touch other components.

3) Visually inspect the code plug for obvious damage, corrosion or loose seating. If it looks loose, you may carefully unplug and reseat it, making sure the connector sits squarely. Refit the casing, restore power and check the display.

4) If reseating clears the error temporarily but it returns, do not attempt further internal work. Photograph the code plug label/part number to show the engineer.

When to call a professional and what to tell them:

1) If the error persists after a power-cycle and careful reseat, or if you are not comfortable opening the boiler casing, call a Gas Safe registered engineer. This fault usually requires a trained engineer to confirm the correct HCM/code plug part, and to replace or reconfigure it safely.

2) When booking the engineer, give them: boiler model and serial number, the exact error code (360 V), any additional cause codes or symptoms, and a note if any recent parts or controls were changed. Provide photos of the boiler front display and the code plug label if you have them.

3) Ask the engineer to check that the fitted code plug/HCM is the correct factory part for that exact Greenstar 8000 variant and to verify the control box firmware/compatibility. Only a qualified engineer should replace the HCM or code plug and then test the boiler operation and safety circuits.

Other notes:

1) Do not attempt to bypass safety interlocks or jury-rig connections to clear the error. That creates a dangerous condition.

2) Keeping a record (photos, dates, any steps tried) will help the Gas Safe engineer diagnose the problem faster.

3) If your boiler is under warranty or service agreement, contact Worcester Bosch support or your service provider and mention the 360 V incompatibility fault so authorised parts and service can be arranged.