125 — No circulation safety trip

What does 125 mean?

The boiler has shut down due to a lack of water circulation, detected by a temperature sensor. This is a safety measure to prevent overheating.

• Blocked pump or faulty pump operation
• Air trapped in the heating circuit
• Closed valves preventing flow

Click steps to track your progress.

1. 1

   Press and hold down the Reset button for 2 seconds to try clearing the fault.

2. 2

   Check the system pressure and top up if necessary as per the 'FILLING THE SYSTEM' section.

3. 3

   Bleed any radiators in the system to remove trapped air. Ensure all radiator valves are fully open.

4. 4

   If the fault persists, contact an Authorised Service Centre to check pump operation and circulation.