When relining a chimney, you insert a stainless steel pipe into the existing shaft. The cross-section of this liner is the critical question: if it is too large, the old shaft limits you; if it is too small, the flow resistance uses up the available draught.
DruckZugPro calculates the optimal inner diameter for the new liner based on your appliance data and the existing chimney geometry.
Highlights
- Calculates minimum and optimal cross-section for the liner.
- Accounts for the insulation effect of the air gap between liner and old shaft.
- Comparison of different stainless steel variants possible.
How it works
- Enter your appliance data (nominal output, exhaust temperature, mass flow).
- Describe the old chimney: inner dimensions of the shaft, height, material.
- Select the desired liner material (stainless steel in various wall thicknesses).
- DruckZugPro shows the appropriate diameter and whether draught is sufficient.
FAQ
When is chimney relining necessary?
Typical triggers: switching from oil to gas (condensing boilers need a moisture-resistant flue), condensation damage on the existing chimney, or connecting a new wood stove to an oversized old chimney.
Which stainless steel variant is the right one?
Depends on the fuel. For wood and pellets a standard stainless steel liner is usually sufficient. For oil the material must be W3-rated (corrosion-resistant for liquid fuels). Thin-walled liners have less thermal mass, which affects draught during cold starts. DruckZugPro factors in the wall thickness.
Does the air gap between liner and old shaft affect the calculation?
Yes. The air gap acts as additional insulation. DruckZugPro accounts for this automatically. Ventilated systems with an open gap are calculated differently from backfilled ones.