EF 349 — Central heating boil detected

What does EF 349 mean?

A central heating boil has been detected. The boiler is operating at minimum burner load with a temperature difference greater than 18°C between flow and return.

• Insufficient water circulation.
• Restricted flow in the heating system.
• Sludge or debris in the heat exchanger.
• Faulty temperature sensors.

Click steps to track your progress.

1. 1

   Check the system pressure and top up if it is low.

2. 2

   Ensure all radiator valves are fully open to allow water circulation.

3. 3

   Reset the boiler. If the 'boil' condition persists, contact a qualified heating engineer to investigate circulation and blockages.