Original Defro Map stone with secondary air opening for boiler accessories

Original Defro DS 25 and 32 kW secondary stone

Firebrick with secondary air openings

Defro DS 25/32 kW firebrick with secondary air openings consisting of two half shells.
Dimensions (HxWxD): 80x400x95mm

Why does fireclay deteriorate over time?

Due to the large proportion of mineral substances, fireclay also has a small disadvantage: it is relatively brittle.

Due to constant exposure to high heat, it will eventually crack.

These are the first signs of wear and tear on the material, but not yet a reason to replace it.

The replacement of fireclay should only be carried out when parts of the material fall out and the protection of the furnace can no longer be guaranteed.

The fireclay should therefore always be checked during stove maintenance.

Original Defro DS 25 and 32 kW secondary stone

Two questions keep coming up in this context:

Is a broken firebrick after a long firing covered by the warranty? No.

The combustion chamber lining is treated as a wear part.

Does the stove manufacturer, chimney sweep or dealer have to replace the fireclay?

Here too, a clear no:

The stove operator is responsible for lining the firebox. While you could hire a professional, anyone with handyman skills can also do the replacement themselves.

Another good news: The replacement material is much cheaper than you might think.