Boiler went through 5 ignition attempts and never detected flame or flame sense value never reached minimum threshold for boiler model
The IGNITION FAULT error code on Weil-Mclain boilers indicates boiler went through 5 ignition attempts and never detected flame or flame sense value never reached minimum threshold for boiler model.
Weil-Mclain IGNITION FAULT means: boiler went through 5 ignition attempts and never detected flame or flame sense value never reached minimum threshold for boiler model. On this component the documented failure modes are no gas reaching the burner, or the gas supply is shut off, ignition or detection electrode dirty, worn or out of position or flue or air intake blocked or restricted. You can safely reset the boiler once — if IGNITION FAULT returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does IGNITION FAULT Mean
The IGNITION FAULT code is shown by the boiler’s control board when it detects boiler went through 5 ignition attempts and never detected flame or flame sense value never reached minimum threshold for boiler model. 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 IGNITION FAULT 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 11 different manufacturers.
| Cause |
|---|
| No gas reaching the burner, or the gas supply is shut off |
| Ignition or detection electrode dirty, worn or out of position |
| Flue or air intake blocked or restricted |
| Mains gas pressure too low |
| Faulty gas valve, or its wiring and connector |
Safety Warning
IGNITION FAULT 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
Check condensate trap for blockage allowing condensate to accumulate inside heat exchanger. Check ignition cable connection
Fouled, worn, bent, or faulty igniter. Fouled igniters can be cleaned for additional use with steel wool. Worn or badly fouled igniters should be replaced with the proper repair part. Igniter rods should be parallel with a 3.5 mm (0.138 in) spark gap. NOTICE: Thin white deposits on the igniter are typical, but brown or black deposits could be the result of flue gas recirculation. Thoroughly inspect the venting system and termination for the possibility of leakage or flu
Check that the gas service valve is open and that other gas appliances in the property work. If they do not, the problem is the gas supply, not the boiler.
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.
Inspect the flue and air intake along their whole length, including the outside terminal, and clear any obstruction or debris.
Have the inlet gas pressure measured at the boiler with a manometer and compared against the figure in the manufacturer’s data table.
Refer to the Weil-Mclain service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Weil-Mclain models that can display fault code IGNITION FAULT:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Weil-Mclain models | — | Possible |
Frequently Asked Questions
Check condensate trap for blockage allowing condensate to accumulate inside heat exchanger. Check ignition cable connection. According to the technical documentation, this is the first check on the list for IGNITION FAULT.
IGNITION FAULT is not classified as a high-severity fault, so the boiler can be reset once. If IGNITION FAULT comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.