No flame signal after ignition
The 227 error code on Bosch-Junkers boilers indicates no flame signal after ignition.
Bosch-Junkers 227 means: no flame signal after ignition. On this component the documented failure modes are no gas reaching the burner, or the gas supply is shut off, flue or air intake blocked or restricted or ignition or detection electrode dirty, worn or out of position. You can safely reset the boiler once — if 227 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does 227 Mean
The 227 code is shown by the boiler’s control board when it detects no flame signal after ignition. 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 227 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 |
|---|
| No gas reaching the burner, or the gas supply is shut off |
| Flue or air intake blocked or restricted |
| Ignition or detection electrode dirty, worn or out of position |
| Faulty gas valve, or its wiring and connector |
| Control board (PCB) faulty |
Safety Warning
227 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 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 flue and air intake along their whole length, including the outside terminal, and clear any obstruction or debris.
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.
Only after every other check: verify the board’s supply and connections, and replace the board — fitting the correct boiler chip card or coding key where the model requires one.
Refer to the Bosch-Junkers service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Bosch-Junkers models that can display fault code 227:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Bosch-Junkers models | — | Possible |
Frequently Asked Questions
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. According to the technical documentation, this is the first check on the list for 227.
227 is not classified as a high-severity fault, so the boiler can be reset once. If 227 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.