Error F9, L9, F8 or L8

Safety precautions:

- If you smell gas, leave the property immediately and call the gas emergency number; do not operate electrical switches.

- Switch the boiler off at the fused spur or main switch before touching the boiler or removing the casing. Wait a minute after power-off.

- Do not open or work on gas or live electrical parts unless you are qualified. Do not bypass any safety interlocks.

- Record the boiler model, serial number and the exact fault code(s) and any recent work or changes before calling an engineer.

Initial homeowner checks (safe, non-invasive):

1. Record the exact fault code shown (F9, L9, F8, L8) and any sequence or other codes displayed. Note whether you have lost heating, hot water, or both.

2. Try a simple reset: switch the boiler off at the fused spur, wait 30–60 seconds, then switch it back on and attempt a restart using the boiler’s restart button. If the code clears and the boiler runs normally for a while, note how long it runs and if the code returns.

3. Check for obvious signs around the boiler: any recent condensation/leaks, water on or beneath the unit, burn or scorch marks around the control area, or signs of recent electrical work or PCB replacement.

4. If the boiler was recently serviced or a PCB was replaced, contact the installer or service company first — a wrong or unprogrammed chip card (BCC) or incorrect board fitment is a common cause.

5. Check the fused spur and household mains supply: ensure the boiler is receiving normal electricity (no tripped RCD/MCB) and there is not a known low-voltage issue in the property.

Specific diagnostic and guidance steps (for a qualified engineer or a competent person only):

1. Visual inspection of PCB: with power isolated, remove the casing and inspect the PCB for corrosion, water damage, swollen components or burn marks and check connector seating. Do not touch live terminals.

2. Check connectors and harnesses: reseat plugs and ribbon cables to the PCB if loose (only if competent). Check earth and neutral connections.

3. Verify boiler chip card (BCC): if the PCB or chip card has been changed recently, confirm the correct chip card is fitted and that it is seated correctly. Some boards require activation/programming to match the boiler serial; an installer/engineer will have the required tools.

4. Run full electrical and sensor checks: check continuity and voltages to key components (flow/return thermistors, pressure switch, fan, gas valve, pumps) to see if a peripheral fault is reporting back as a PCB error.

5. Check for error history and diagnostic menu: an engineer can access the boiler’s service menus to read logged faults and status flags which point to whether the PCB itself is failing or being alerted by a faulty peripheral.

6. If PCB fault confirmed: replacement or reprogramming of the PCB will likely be required. This must be done by a Gas Safe registered engineer or an authorized Ideal service technician who can fit the correct PCB/chip and carry out commissioning and safety checks.

When to call a professional:

- If the basic reset and visual, non-invasive checks do not clear the fault, call a Gas Safe registered engineer.

- If you find water damage, scorch marks, loose wiring, or if the fault repeats after reset, do not attempt PCB replacement yourself.

- If a PCB or chip card needs replacing or configuring, this must be done by a qualified engineer who will test gas safety, ignition, flue, sensors and all safety interlocks after repair.

Final note: PCB/control faults affect gas safety and boiler operation. Do the safe checks above, record the fault details and contact a Gas Safe engineer or Ideal Heating support to diagnose and repair. Do not continue to attempt invasive repairs if you are not qualified.