F83 Fault — Insufficient temperature change at start-up

What does F83 mean?

When the burner starts, the flow and/or return temperature sensors register little to no temperature change, suggesting insufficient water flow or sensor placement issues.

• Insufficient water in product
• Flow or return temperature sensor not in correct position at pipe
• Thermistors resistance issue
• Blocked rubber tube on flow pipe
• Pump not spinning correctly

Click steps to track your progress.

1. 1

   Check the boiler's water pressure and ensure there is sufficient water in the system.

2. 2

   Verify that the flow and return temperature sensors are correctly positioned and have good contact with the pipes.

3. 3

   Check the resistance readings of the thermistors and inspect their leads (requires specialist tools).

4. 4

   Check if the pump is spinning correctly (requires specialist tools).

5. 5

   If present, check the rubber tube on the flow pipe; if it feels hard, it may be blocked.