No flame detected – The boiler will make three attempts at ignition before the control goes into this lockout condition
The F09 error code on Peerless boilers indicates no flame detected – the boiler will make three attempts at ignition before the control goes into this lockout condition.
Peerless F09 means: no flame detected – the boiler will make three attempts at ignition before the control goes into this lockout condition. On this component the documented failure modes are wiring, connector or harness of the false flame damaged or loose, ignition or detection electrode dirty, worn or out of position or faulty gas valve, or its wiring and connector. You can safely reset the boiler once — if F09 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does F09 Mean
The F09 code is shown by the boiler’s control board when it detects no flame detected – the boiler will make three attempts at ignition before the control goes into this lockout condition. The boiler then stops instead of continuing to run in that condition: the code is the appliance reporting a problem, not proof that the boiler is broken.
| What you see on the boiler |
|---|
| The display shows F09 and the boiler stops until the fault is cleared |
Common Causes
The manufacturer does not publish a cause list for this specific code. The causes below are the failure modes documented for the same component on other boilers, confirmed by the service literature of 6 different manufacturers.
| Cause |
|---|
| Wiring, connector or harness of the false flame damaged or loose |
| Ignition or detection electrode dirty, worn or out of position |
| Faulty gas valve, or its wiring and connector |
Safety Warning
F09 involves electrical or pressure-related components. Do not attempt repairs without proper qualifications. Ensure the boiler is electrically isolated before any inspection. If you notice water leaks, unusual sounds, or pressure anomalies, contact a qualified heating engineer immediately.
Parts & Prices
Prices shown are indicative. Actual prices and availability vary by region.
How to Fix It
1. Watch the igniter through the observation window provided. 2. If there is no spark, check the spark electrode for the proper ¼" gap. 3. Remove any corrosion from the spark electrode. 4. If there is a spark but no flame, check the gas supply to the boiler. 5. If there is a flame, check the flame sensor
Unplug and re-seat the connector of the false flame, then check the harness for chafing, corroded pins and breaks in continuity.
Inspect the ignition and detection electrode: clean off any deposits, check the gap and position against the manual, and replace it if it is worn.
Check the gas valve connector and wiring for continuity, then test the valve coil resistance against the manual; replace the valve if it is out of range.
Refer to the Peerless service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Peerless models that can display fault code F09:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Peerless models | — | Possible |
Frequently Asked Questions
1. Watch the igniter through the observation window provided. 2. If there is no spark, check the spark electrode for the proper ¼" gap. 3. Remove any corrosion from the spark electrode. 4. If there is a spark but no flame, check the gas supply to the boiler. 5. If there is a flame, check the flame sensor. According to the technical documentation, this is the first check on the list for F09.
F09 is not classified as a high-severity fault, so the boiler can be reset once. If F09 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.