Boiler displays E20 and shuts down, often when condensate drainage is restricted.
Safety Warning
This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.
If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.
Possible Causes
How to Fix / Troubleshooting
Safety: Condensate is mildly acidic; wear gloves and eye protection when handling. Isolate power before opening the boiler.
User checks:
- Inspect the external condensate pipe for freezing in cold weather; thaw gently with warm water and lag the pipe to prevent recurrence.
Engineer checks:
- Remove and clean the condensate trap on the EHC boiler; flush out sludge and debris.
- Check the condensate pipework for correct fall and no kinks or blockages.
- Test the condensate level sensor or float switch for correct operation; replace if sticking or faulty.
After clearing the blockage and checking the sensor, reset the boiler and confirm normal condensate discharge.
Repair Difficulty
Required Part
We may earn a commission from links on this page.