Potterton E28 Fault

Potterton E28 Fault

The Potterton E28 error code indicates a fault with the flue thermistor. This component measures the temperature of the gases in the flue system, ensuring that the boiler operates safely and efficiently by monitoring the exhaust gas temperatures. A fault in the flue thermistor can affect the boiler’s ability to safely vent exhaust gases and may lead to operational issues.

Causes of Potterton E28 Error Code

  1. Faulty Flue Thermistor: If the flue thermistor is damaged or malfunctioning, it may provide incorrect temperature readings or fail to monitor the flue gas temperatures accurately.
  2. Wiring Issues: Problems with the wiring connections between the flue thermistor and the boiler’s control board can disrupt the transmission of temperature data, leading to fault readings.
  3. Blockages in the Flue System: Any blockage in the flue can affect the temperature of the gases being vented, which may be incorrectly interpreted by a faulty thermistor.
  4. Incorrect Installation: If the flue thermistor is not installed correctly or has become dislodged, it may not accurately measure the flue gas temperatures.

Troubleshooting and Resolving the Potterton E28 Error Code

  1. Inspect the Flue Thermistor: Check for any visible signs of damage to the flue thermistor. If it appears to be faulty, it will need replacing.
  2. Check Wiring and Connections: Ensure that all electrical connections between the flue thermistor and the boiler’s control board are secure and in good condition. Repair or replace any damaged wiring.
  3. Clear Flue Blockages: Inspect the flue for any blockages that could affect gas venting and remove them if found. Ensure the flue system is clear to allow for proper exhaust gas ventilation.
  4. Verify Thermistor Installation: Make sure the flue thermistor is correctly installed as per the manufacturer’s guidelines. If unsure, seek professional assistance for verification and correction.
  5. Reset the Boiler: After addressing any issues with the flue thermistor or the flue system, try resetting the boiler to see if the error code clears and normal operation resumes.
  6. Seek Professional Help: If the E28 error persists or you’re unsure how to proceed, it’s advisable to contact a Gas Safe registered engineer. A professional can accurately diagnose the issue and replace the flue thermistor if necessary.
  7. Regular Maintenance: To prevent future issues, including the E28 error, ensure your boiler and flue system receive regular professional maintenance. This can help identify and resolve potential problems before they lead to significant faults.


The Potterton E28 error code signifies a fault with the flue thermistor, requiring prompt attention to ensure the boiler’s safe and efficient operation. While some preliminary checks can be performed by the homeowner, resolving issues related to the flue thermistor often necessitates professional intervention. Regular servicing and maintenance can help maintain optimal boiler performance and prevent similar faults.