Boiler Error Code: What It Means, What to Do

Error code on your combi boiler display: what it means and what to do

When the boiler detects a problem, it shuts itself down safely and shows a code on the display. What the code means depends on the brand and model, but most codes fall into one of a few main groups.

If you smell gas, safety comes first

Do not touch any electrical switches or the boiler, and do not light any flame. Open the windows, turn off the gas valve at the meter, leave your home and call 187, the gas emergency line, from outside.

İlhan speaks only Turkish. Write to us in English on WhatsApp: he reads your message and replies with a translation app.

In short

The same code can mean different things on different boilers; the exact meaning is in the user manual.
First check the pressure, the gas valve and the power supply; then press the reset button once.
If the code keeps coming back, do not press the reset button again and again. Take a photo of the code and send it to a technician.

What do the codes usually indicate?

No ignition, no flame detected: Gas may not be reaching the boiler; the gas valve may be closed, the credit on a prepaid (card) gas meter may have run out, or an ignition part may be faulty.
Low water pressure: The system has lost some water. Why does the pressure drop?
Overheating: The water may not be circulating; the pump, a blockage or air may be the cause.
Flue, fan or air flow: The combustion gases are not being carried outside properly. These codes are important for safety.
Sensor or electronic board: A temperature sensor or the board is reporting a fault.

What should you do, step by step, when a code appears?

Write the code down or take a photo of the display.
Look at the pressure gauge; if it is below 1 bar, add water.
Check that the gas valve is open. If your hob lights, gas is reaching your home. If you have a prepaid (card) meter, check the credit.
Check that the boiler is plugged in and that its circuit breaker is on.
Press the reset button once and wait a few minutes.

What not to do

If the code keeps coming back, do not press the reset button again and again. This can be dangerous, especially with flue and ignition codes.
Do not open the boiler cover; there are gas and electrical connections inside.
Do not trust code explanations online that were written for a different boiler; the same code may mean something else on your boiler.

What should you tell the technician?

The brand and model of the boiler (written on the label just below the front cover), the code on the display and when it appeared are enough. If you send a photo of the code on WhatsApp, it is often possible to get a rough idea in advance of where the problem is.

Dereli Teknik · 25 September 2026

Message us on WhatsApp

Just tell us your boiler's brand and the problem. İlhan speaks only Turkish: write in English and he replies using a translation app. From a photo of the display or the error code we can often tell roughly what the fault is.