The E030 fault code appears on 2 boiler brands — Navien and Vokera — and on all of them it points to the same kind of problem. The details still differ by brand (thresholds, sub-codes, reset procedure), so use the table below to jump to the page for your boiler.
The brand is printed on the front casing. Tap your brand for the full causes, fixes and repair costs.
| Brand | What E030 means | Severity | DIY? |
|---|---|---|---|
| NNavien | The E030 code is a safety lockout triggered when the exhaust gas temperature climbs above approximately 65°C, causing the built-in high-limit switch to shut the boiler down. Full guide → | Lockout — engineer likely | No |
V Vokera | The E030 code means your Vokera boiler has detected a problem with its flue fan and shut itself down as a safety precaution. Full guide → | Lockout — engineer likely | No |
The E030 code is a safety lockout triggered when the exhaust gas temperature climbs above approximately 65°C, causing the built-in high-limit switch to shut the boiler down. In plain terms, the flue gases are hotter than they should be — a sign that exhaust flow is restricted, the combustion system is struggling, or a sensor is giving the control board inaccurate readings. The boiler will not fire again until the underlying fault is identified and resolved.
The E030 code means your Vokera boiler has detected a problem with its flue fan and shut itself down as a safety precaution. The fan is responsible for pushing combustion gases safely out through the flue — without it working correctly, dangerous exhaust gases could back up inside your home. Because of this risk, the boiler's control board refuses to allow normal operation until the fault is resolved. On some Vokera model ranges you may see this displayed as A03 rather than E030, but both point to the same underlying fan malfunction.
Broadly, yes — on Navien and Vokera the E030 code points to the same class of fault, and the recommended response is similar. Model-specific details such as sub-codes and reset procedures still vary, so follow the page for your own brand.
Not usually. On every brand listed, E030 points to a fault that needs a suitably registered engineer to diagnose and repair. A single reset to rule out a transient glitch is reasonable; repeated resets are not.
For gas boilers, a Gas Safe registered engineer — it is a legal requirement for any work on the appliance. If you smell gas at any point, leave the property and call the National Gas Emergency line on 0800 111 999.
General guidance only — not a substitute for professional advice, and not certified by a registered engineer. Any work on a gas appliance must be carried out by a Gas Safe registered engineer. If you smell gas, call 0800 111 999.
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