“I light the fire in the evening, the stove burns beautifully and everything is fine. But when the fire goes out, strange metallic noises come from the stove. Sometimes it really bangs. Could something be broken?”
In most cases, there is no cause for concern.
Crackling, clicking or occasional popping noises during the heating and cooling of the oven are a common physical phenomenon. It is related to the thermal expansion of the materials from which the oven is made.
However, not every noise is automatically harmless.
Why does the oven crackle even though there’s no fire burning in it anymore?
Metal expands when heated and contracts when cooled.
Wood-burning stoves consist of various parts that do not need to heat up or cool down evenly.
For example, the steel housings, reinforcements, doors or internal metal components may have different temperatures.
When their dimensions change, stresses are released in the material and characteristic noises are produced.
You may hear a faint ticking, clicking, or a more pronounced metallic clanging.
You may be familiar with a similar phenomenon from a metal radiator, which sometimes clicks after the heating has been switched off.
Are steel or cast iron ovens more prone to cracking?
Noise can occur in both components due to thermal expansion.
In steel furnaces, these effects are sometimes more pronounced, as they have more sheet metal parts, connections and possibly convection panels that heat up at different rates.
However, cast iron stoves can also produce similar noises.
Cracks in themselves are therefore not proof of inferior material or poor workmanship.
Why do new ovens crack more often than old ones?
“I bought a new stove, and it kept clicking the first time I turned it on. The old one didn’t do that.”
That can happen too.
With new ovens, the sound of thermal expansion may be more noticeable at first. The individual metal parts gradually settle within the specified tolerances during the initial heating and cooling phases.
Therefore, in some models, these noises may become less noticeable after several floods.
However, this depends on the specific model. Some ovens make audible clicking noises throughout their entire lifespan when the temperature changes.
At what point does cracking become abnormal?
Special attention should be paid if the nature of the sounds suddenly changes significantly or other unusual symptoms occur.
For example:
- The stove starts making very loud banging noises, which were not normal before.
- Visible deformations appear on the metal parts.
- The glass will crack or the structure of the firebox will be damaged.
- The stove is apparently overheating or burning unusually intensely.
- The door no longer fits properly and no longer seals.
In this case, the fire should not be lit again. Have the cause checked after the fire has cooled down safely.
Attention: If, instead of occasional knocking, you hear a loud humming, rumbling or violent cracking from the chimney and suspect a chimney fire, leave the danger zone and call the fire department at 150 or 112.
Is there anything I can do to prevent cracks?
It is impossible to completely eliminate the natural thermal expansion of materials.
However, you can follow some simple principles.
Use only the recommended amount of fuel, do not exceed the operating power specified by the manufacturer, and do not overheat the stove.
When adjusting the lighting and lighting, please refer to the instructions for the specific model.
Do not attempt to eliminate the noise by arbitrarily loosening screws, modifying metal parts, or removing internal components.
If a mechanical problem is suspected, a professional inspection is advisable.
What can you take away from this?
Occasional clicking, ticking or metallic banging noises when a wood-burning stove heats up and cools down are usually a natural consequence of the thermal expansion of the materials.
The fact that a furnace sometimes develops cracks after it has gone out does not mean that its structure is damaged.
However, if unusually loud banging noises, deformations or other signs of improper operation occur, the cause must be determined.
What is crucial is not only the sound itself, but also the timing of its occurrence and whether it is accompanied by other unusual phenomena.