Your boiler has stopped and there's a code flashing on the display. It could be E1, F7, A-03 — something that means nothing to you at 7am on a cold morning. The good news: most boiler error codes in the Netherlands are not serious. Many can be resolved in minutes without calling anyone. This guide explains what the most common codes mean, what you can safely try yourself, and when it's time to call a plumber.

How Boiler Error Codes Work

Modern CV ketels (central heating boilers) have built-in diagnostics that detect faults and lock the boiler to prevent damage. When something goes wrong, the boiler displays a code and shuts down — a safety feature, not a failure. The most common brands in Dutch homes are Intergas, Nefit, Remeha, Vaillant, and HR Kombi. Each brand uses its own code system, so the same problem might show as "E3" on one brand and "F22" on another.

Before calling a plumber, it's always worth doing a basic reset. On most boilers, you hold the reset button for 3–5 seconds. If the boiler fires up and runs normally, you're done. If it locks out again within the hour, the underlying cause needs to be found.

The Most Common Error Codes — and What They Mean

No hot water or heating / boiler won't fire
Brands: Intergas E1, Nefit E2, Vaillant F22, Remeha E118
This usually means low water pressure. Check the pressure gauge on the front of your boiler — it should sit between 1.5 and 2 bar when cold. If it's below 1 bar, you need to top up the system. There's a filling loop (a small silver or grey handle) connected to your boiler. Open it slowly until the pressure reaches 1.5 bar, then close it again. Reset the boiler. This is one of the most common calls we get — and the easiest fix.

Ignition failure / boiler clicks but won't light
Brands: Intergas E2, Nefit E3, Vaillant F28, Remeha E117
The boiler is trying to ignite but failing. This can happen after the gas has been off (roadworks, meter work), or if there's air in the gas line. Try resetting 2–3 times. If it still won't light, check that other gas appliances in your home work — if your hob has no gas either, the problem is with the supply, not the boiler. Call your gas provider. If the hob works fine but the boiler won't ignite, call a plumber.

Flue or ventilation fault
Brands: Vaillant F61, Remeha E110, Nefit E9
This means the boiler can't safely exhaust combustion gases. The flue pipe (usually going through an outside wall) may be blocked — by a bird's nest, debris, or ice in very cold weather. Check if anything is blocking the external vent. Never attempt to clean or modify the flue yourself. If it looks clear but the code persists, call a certified engineer.

Overheating / high temperature fault
Brands: Intergas E5, Vaillant F75, Nefit E5, Remeha E119
The boiler has detected unusually high temperatures and shut down to protect itself. This often points to a circulation problem — a pump that isn't moving water properly, or a radiator system with a lot of air in it. Try bleeding your radiators (use a radiator key to open the bleed valve slightly until water comes out steadily, then close). If the error returns, the pump may need to be checked by a plumber.

Sensor or circuit board fault
Brands: Various — typically shown as F3, E6, A-04, or similar
If the error code doesn't match any of the above and a reset doesn't help, it's likely an internal sensor or electronic fault. These can't be diagnosed or fixed without the right equipment. Call a plumber — don't keep resetting, as repeated lockouts on a faulty sensor can mask a more serious problem.

What You Can Safely Do Yourself

Top up the water pressure, bleed your radiators, check the gas supply, and reset the boiler once or twice. That covers the majority of error codes that come up in everyday use. Beyond that — anything involving the gas connection, the flue, the pump, or internal components — needs a certified professional. In the Netherlands, gas work must be carried out by a recognised installer (erkend installateur). Your English Plumber's engineers are fully certified and work across Amsterdam, Rotterdam, Utrecht, Den Haag, and surrounding areas.

Still Seeing an Error Code? We Can Help.

Tell us the brand of your boiler and the code on the display, and we'll tell you straight away whether it's something you can fix or whether we need to come out. We're available 24/7 — including evenings and weekends — and typically on-site within 2 hours.

📞 Call 06-24356980 — available 24/7
💬 WhatsApp: wa.me/31624356980