E110 — Boiler max temperature exceeded (overheat)

What does E110 mean?

The boiler has detected that its internal temperature has exceeded a safe maximum limit, either rapidly (gradient) or due to general overheating. This often triggers a safety thermostat.

• Poor water circulation in the heating system (e.g., blocked or jammed pump).
• Air in the heating circuit.
• Faulty safety thermostat or temperature sensor.
• Closed isolation valves.

Click steps to track your progress.

1. 1

   Press the 'Reset' button on the boiler for 1-3 seconds.

2. 2

   Ensure all heating system valves (radiators, main flow/return) are open.

3. 3

   Check the system water pressure; if it's too low, re-pressurize the system.

4. 4

   If the error persists, a qualified technician should inspect the pump, check for air in the system, and verify the safety thermostat.