Alpha E50 Fault

Alpha E50 Fault

The Alpha E50 error code signifies a fault with the Domestic Hot Water (DHW) temperature sensor. This sensor monitors the temperature of the hot water being supplied to taps and showers. A malfunction or discrepancy in the sensor’s readings can lead to issues with water temperature regulation, potentially resulting in water that’s too hot or too cold for comfort and safety.

Causes of Alpha E50 Error Code

  1. Faulty DHW Temperature Sensor: The sensor itself might be malfunctioning or damaged, leading to incorrect temperature readings.
  2. Wiring Issues: Problems with the electrical connections between the DHW temperature sensor and the boiler’s control unit can cause inaccurate temperature data transmission.
  3. Limescale Build-up: Accumulation of limescale around the sensor can insulate it, affecting its ability to accurately measure water temperature.
  4. Poor Sensor Placement: If the sensor is not correctly positioned within the hot water system, it may not accurately reflect the true water temperature.

Troubleshooting and Resolving the Alpha E50 Error Code

  1. Inspect and Clean the Sensor: Check the DHW temperature sensor for any visible signs of damage or build-up. Carefully cleaning the sensor might help improve its accuracy.
  2. Check Wiring Connections: Ensure all connections between the sensor and the boiler’s control unit are secure and in good condition. Repair or replace any damaged wiring.
  3. Descale the Hot Water System: If limescale is suspected to be affecting the sensor’s performance, consider descaling the hot water system. This task is often best left to a professional.
  4. Verify Sensor Placement: Check that the DHW temperature sensor is correctly positioned as per the manufacturer’s instructions. Adjustments or repositioning may require professional assistance.
  5. Reset the Boiler: After addressing potential issues, reset the boiler to see if the error code clears and normal operation resumes.
  6. Professional Diagnosis and Replacement: If the problem persists or you’re unsure how to proceed, it’s advisable to consult a Gas Safe registered engineer. A professional can accurately diagnose the issue and replace the DHW temperature sensor if necessary.
  7. Regular Maintenance: To prevent future occurrences of error code E50 and other issues, ensure your boiler and hot water system receive regular maintenance from a qualified technician. This can help identify and resolve potential problems early on.


The Alpha E50 error code highlights a problem with the Domestic Hot Water temperature sensor, requiring prompt attention to maintain proper hot water temperature regulation. While some initial checks and cleaning can be done by homeowners, more complex issues related to sensor functionality or system descaling typically necessitate professional intervention. Regular servicing can help maintain optimal system performance and prevent similar faults.