Potterton E125 fault code explained

E125 on a Potterton boiler means a water circulation fault, according to Baxi’s official error-code table. The boiler has not detected the movement of heating water it expects and may lock out to protect itself.

Keep the boiler casing closed. Check only the external pressure gauge and visible parts of the heating system. If the correct user guide allows a normal reset, try it once after the boiler has cooled. If E125 returns, arrange a Gas Safe registered engineer.

Which Potterton boilers use E125?

Baxi’s current error-code table includes E125 in the group covering Potterton Assure Combi and Potterton Assure System boilers. Potterton has made many other ranges, so do not assume the same code applies to every model. Record the complete model name from the outside of the appliance and check its official manual.

What does a water circulation fault mean?

The boiler expects heating water to carry heat away through the system. E125 indicates that this circulation is not happening as expected. The code does not identify one failed component and should not be used as a reason to order a pump or sensor without proper checks.

What can I safely check?

• Photograph the E125 display and external pressure gauge.
• Compare the pressure with the normal cold range in the model’s user guide.
• Check whether all, some or none of the radiators are warming.
• Make sure radiator valves intended to be open have not all been closed.
• Look for visible leaks around radiators, accessible pipework and beneath the boiler.
• Note any recent radiator bleeding, plumbing work or control changes.
• Listen for unusual banging or rushing-water sounds without touching the appliance.
• Check you haven’t accidently closed of the incorrect valves when repressurising the boiler

Do not remove the case, touch the internal pump, move wiring, dismantle valves or bypass the lockout. If pressure is low, follow only the exact repressurising instructions for the model and stop if anything is unclear or leaking.

Can I reset Potterton E125?

Allow the boiler to cool first. If the manufacturer’s guide permits a homeowner reset, try it once. If the code clears and then returns when heating or hot water is requested, the circulation fault has not been repaired.

Repeated resets are not a solution and may remove useful information about when the fault occurs.

What can interrupt circulation?

Possible causes include air in the heating circuit, incorrect system pressure, restricted water flow or a component that is not moving water correctly. Only model-specific checks can establish which applies. Internal work can involve hot water, electricity and gas-appliance safety systems and must be left to a competent engineer.

When should I turn the boiler off?

Turn it off and arrange prompt help if E125 keeps returning, the boiler or nearby pipes become unusually hot, there is severe banging, or water is leaking near electrical parts. If you smell gas or a carbon-monoxide alarm sounds, follow Gas Safe Register emergency guidance and do not reset or repressurise the boiler.

What should I provide when booking?

Have the full model, photos of the code and gauge, details of which radiators heat, any visible leaks, recent heating-system work and the result of the single reset. This helps the engineer arrive prepared while you avoid unsafe investigation.