Potterton E125 Fault

Potterton E125 Fault

The Potterton E125 error code indicates a circulation fault within the boiler system. This fault is triggered when there’s an issue with the flow of water through the boiler, suggesting that the hot water is not being effectively circulated through the system. This can lead to inefficient heating and, in some cases, may prevent the boiler from operating.

Causes of Potterton E125 Error Code

  1. Faulty Pump: The circulation pump may be malfunctioning or seized, preventing the proper flow of water through the system.
  2. Blocked Pipes or Heat Exchanger: Sludge or scale buildup within the pipes or heat exchanger can restrict water flow, leading to circulation issues.
  3. Airlocks: Air trapped within the system can impede water flow, creating circulation problems.
  4. Closed or Partially Closed Valves: Valves that are not fully open can restrict the flow of water, affecting circulation.

Troubleshooting and Resolving the Potterton E125 Error Code

  1. Check the Pump: Ensure the pump is operational. Listen for any sounds from the pump to determine if it’s running. A non-functioning pump may need to be replaced by a professional.
  2. Inspect for Blockages: Look for signs of sludge or scale buildup in the system, particularly within the heat exchanger or pipes. A system flush conducted by a professional can help remove these blockages.
  3. Bleed the System: Release any trapped air from radiators and the heating system to eliminate airlocks that could be affecting water circulation.
  4. Verify Valve Positions: Check that all valves in the heating system are fully open to allow unrestricted water flow.
  5. Reset the Boiler: After addressing any issues, reset the boiler to clear the error code and attempt to restart the system. Refer to the boiler’s manual for specific reset instructions.
  6. Seek Professional Help: If the circulation issue persists or you’re unable to determine the cause, it’s advisable to contact a Gas Safe registered engineer for a thorough diagnosis and repair. Circulation faults can sometimes be complex, requiring professional expertise to resolve.


The Potterton E125 error code is an indication of a circulation fault that needs prompt attention to ensure the efficient operation of your heating system. While homeowners can perform some basic checks and attempts at resolution, such as bleeding radiators and checking the pump, more complex issues like blockages or a faulty pump will likely require professional intervention. Regular maintenance can help prevent circulation problems by ensuring that the system remains clean and all components are in good working order.