Over temperature protection intervention
The A08 error code on Ferroli boilers indicates over temperature protection intervention.
Ferroli A08 means: over temperature protection intervention. The usual causes are sensor not correctly positioned on the delivery pipe or damaged, lack of water circulation in the system or presence of air in the system. You can safely reset the boiler once — if A08 returns, do not keep resetting. A qualified heating engineer should diagnose the root cause.
What Does A08 Mean
The A08 code is shown by the boiler’s control board when it detects over temperature protection intervention. 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 A08 and the boiler stops until the fault is cleared |
Common Causes
Causes documented in the Ferroli service literature published by centriassistenza.org, cross-checked against the manufacturer’s fault-code table.
| Cause |
|---|
| Sensor not correctly positioned on the delivery pipe or damaged |
| Lack of water circulation in the system |
| Presence of air in the system |
Safety Warning
A08 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 the correct positioning and functioning of the heating sensor and replace it if necessary
Check the circulation pump
Vent the system
Refer to the Ferroli service documentation for the detailed procedure. Only a qualified engineer should carry out these repairs.
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Affected Models
Ferroli models that can display fault code A08:
| Model Family | Output Range | Frequency |
|---|---|---|
| All Ferroli models | — | Possible |
Frequently Asked Questions
Check the correct positioning and functioning of the heating sensor and replace it if necessary. According to the technical documentation, this is the first check on the list for A08.
A08 is not classified as a high-severity fault, so the boiler can be reset once. If A08 comes back, stop resetting: the underlying cause is still there and needs a qualified heating engineer.