Ideal F2 Fault Code
The F2 fault means the PCB cannot confirm the fan is running correctly, or the air pressure switch has not made during the proving sequence. The boiler refuses to ignite until it can confirm the flue is clear.
What is the Ideal F2 fault code?
The Ideal F2 fault is triggered when the control board does not receive confirmation from the air pressure switch (APS) within the expected time after the fan starts. The APS is a safety device that proves the flue gases can escape before ignition is permitted. If the APS does not make contact — whether because the fan is not running, the flue is blocked, or the APS itself has failed — the boiler locks out with F2.
What causes the F2 fault?
The fan motor degrades over time. A failing motor may run too slowly to generate sufficient flue draught, preventing the APS from making contact.
A bird nest, debris, or partial obstruction at the flue outlet restricts airflow and trips the F2 lockout even if the fan is running correctly.
The APS diaphragm can crack or the contacts can fail. The boiler shows F2 even when the fan is running correctly because the switch cannot signal "clear".
A cracked or disconnected rubber hose between the APS and the fan assembly prevents the switch from detecting fan pressure.
A blocked condensate trap creates backpressure in the flue gas path, mimicking a blocked flue and preventing the APS from making.
In winter, a frozen condensate pipe causes the same backpressure effect — F2 appears but resolves immediately once the pipe is thawed.
What you can safely check yourself
If safely accessible, inspect the flue terminal for obvious blockages such as bird nests or debris. Do not reach inside the flue terminal.
During cold weather, thaw a frozen condensate pipe with warm (not boiling) water poured over the external section. Then reset the boiler.
Hold the reset button for 3 seconds. If F2 returns immediately, the fan, APS, or flue needs professional attention.
Do not reset the boiler more than once if the fault code returns immediately. Repeated resets without diagnosis can mask a worsening fault.
What needs a Gas Safe engineer
- Test fan motor speed and current draw
- Inspect flue terminal and flue run for blockages
- Test air pressure switch continuity and switching pressure
- Inspect APS hose for splits or disconnection
- Clear or replace blocked condensate trap
- Check PCB fan control circuit if all components test correctly
Fan faults are common across South London's older housing stock. Many properties in Wandsworth, Merton, Lewisham, Lambeth, Southwark, Greenwich, and Bromley run Ideal Logic+ boilers that are 8–14 years old — well within the fan motor wear window. Annual servicing includes a fan speed check to catch degradation early.
How much does a F2 repair cost?
Costs below are UK averages. Reion provides a fixed quote after the £80 diagnostic visit — no obligation to proceed.
How to reset a Ideal boiler showing F2
In winter: check and thaw the condensate pipe before resetting.
Check the flue terminal for visible blockages.
Hold the reset button for 3 seconds.
Listen for the fan starting — you should hear it within 5 seconds.
If F2 returns, call a Gas Safe engineer.
Fan replacement is a straightforward repair — typically £200–£380 including parts and labour. On a Logic+ under 10 years old, it is unambiguously worth doing.
Common questions about the Ideal F2 fault
What does F2 mean on an Ideal boiler?
Can I fix an Ideal F2 fault myself?
Why does my Ideal boiler show F2 in cold weather?
How much does an Ideal F2 repair cost in London?
Is an Ideal F2 fault dangerous?
Other Ideal fault codes
Need a Ideal engineer in London?
Reion is Gas Safe registered (919881), based in South London, and available 24/7. Fixed price after the diagnostic visit — no hidden charges.
