E3
Buderus
Primary Flow Overtemperature
Boiler displays E3; burner shuts down due to overheating
Advertisements
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.
Advertisements
Possible Causes
Blocked primary heat exchanger, Pump failure or low speed, Closed valves in heating circuit, Air lock in boiler or system
How to Fix / Troubleshooting
Safety: Allow the boiler to cool fully before working on it. Overheating can cause scalding and component damage.
- 1. Check system pressure and bleed: Ensure pressure is correct and bleed radiators and boiler air vents to remove air.
- 2. Verify pump operation: Listen and feel for the Buderus circulation pump running during a heat demand. If silent or very hot to touch, it may be seized.
- 3. Open all valves: Confirm that all isolation valves near the boiler and on the heating circuit are open.
- 4. Clean filters: Check any system filters or strainers for blockage and clean them.
- 5. Heat exchanger inspection: If E3 recurs, the primary heat exchanger may be scaled or blocked and should be inspected and flushed by a technician.
Advertisements
Repair Difficulty
Hard
4/5
Required Part
Circulation Pump / Primary Heat Exchanger
Check Price on Amazon
We may earn a commission from links on this page.
Advertisements