Product detailed description

Vaillant flue extension 2.0 m, Ø 110 mm

The flue extension with a length of 2.0 metres is the longest straight section in the range of original Vaillant Ø 110 mm shaft system components. Where the shorter 0.5 m and 1.0 m extensions allow fine-tuning of the assembly height to the centimetre, this 2-metre piece serves primarily for quickly and economically covering long straight shaft sections – typically in multi-storey apartment buildings or tall masonry chimneys of family houses, where assembling from shorter pieces would mean unnecessarily many joints.

Vaillant LAS Ø 110 mm shaft flue gas discharge system

This part is part of the original Vaillant shaft flue gas discharge system (abbreviated LAS – from the German "Luft-Abgas-System"), which is used with high-output condensing boilers (typically higher output ranges of ecoTEC exclusiv/pro/plus and floor-standing ecoCRAFT exclusiv boilers, as well as equivalent-output Protherm models from the same manufacturing group). Unlike a standard concentric flue (pipe within a pipe) used with small wall-mounted boilers, the shaft system routes flue gases through a single-wall pipe with a diameter of 110 mm inside an existing building chimney shaft (most often an older masonry chimney no longer used for its original purpose), while combustion air is drawn in through the free space of the shaft around this pipe.

The advantage of this solution is that it does not require any new penetration through the facade or roof in addition to the existing shaft, and in multi-storey buildings it allows routing the discharge to the required height without the need to build a new chimney. All system parts are made of durable polypropylene (PP), which withstands long-term contact with the mildly acidic condensate produced during condensing boiler operation, and are joined using a simple socket-to-socket push-fit system with an integrated sealing ring, without the need for gluing or additional sealing.

Why choose the 2-metre piece

Every push-fit joint in the flue is also a potential point requiring attention during installation to ensure correct insertion and orientation of the sealing ring. When the discharge runs through three, four or more storeys of a shaft, it therefore makes sense to use as few but as long pieces as possible – this reduces the number of joints, shortens installation time and reduces the overall risk of leakage over decades of operation. A 2.0 m piece allows a single piece to span, for example, the height of two typical storeys, with the remaining difference to the exact height then resolved by combining it with a shorter 0.5 m or 1.0 m extension from the rest of the range.

The pipe is made of polypropylene (PP) resistant to condensing boiler flue gas condensate (mildly acidic environment, pH approximately 3–5), with a smooth internal surface minimising pressure losses over the long run and ensuring smooth condensate flow back towards the boiler or to a collection point at the base of the shaft.

Installation into the assembly

The extension is inserted socket-end first into the spigot (smooth end) of the adjacent part – joint tightness is ensured by an integrated rubber sealing ring, which we recommend lightly coating with silicone lubricant intended for plastic piping systems before insertion (this eases insertion and extends the seal's service life). Given the 2 m length, when working in a vertical shaft it is advisable to have a second person or suitable lifting/guiding aids available so that the piece does not bend or get scratched against the shaft walls during insertion.

When installing a long straight section, do not forget a sufficient number of spacer brackets, which centre the pipe within the cross-section of the shaft (typically approximately every 2 metres, exact spacing can be found in the boiler's installation manual), and fixing clamps, which secure the entire column against lateral movement without preventing its free thermal expansion.

Step-by-step installation procedure

1. Before installation, based on the boiler's installation manual and the actual shaft height, prepare an exact list of parts (number and lengths of extensions, bends, inspection pieces) so that the sum of lengths matches the actual route height.
2. Check that the spigot end of the extension and the socket end of the adjacent part are clean, free of mechanical damage and free of deposits from transport.
3. Lightly coat the sealing ring in the socket with silicone lubricant intended for plastic piping systems.
4. Carefully insert the piece into the socket of the previous section of the assembly all the way to the stop, with two people handling it in a vertical shaft due to the 2 m length.
5. Verify that the piece is inserted evenly (without skewing), and continue by connecting the next section of the assembly (bend, further extension, or inspection piece) according to the route design.
6. Install spacer brackets and fixing clamps at appropriate intervals according to the boiler's installation manual.
7. After completing the entire assembly, carry out a visual inspection of all joints and have the handover of the system confirmed by a chimney sweep or inspection technician before first starting the boiler.

Practical example

When replacing an older atmospheric boiler with a high-output condensing boiler in an apartment building with 4 above-ground storeys, the original masonry chimney with an internal cross-section of approximately 30 × 30 cm was used as a protective shaft for the new plastic Ø 110 mm flue. To span a height of approximately 11 metres from the boiler room in the basement to the termination above the roof, four 2-metre extensions were used (8 m total), supplemented by one 2 m and one 1 m piece from the rest of the range for exact adjustment, together with a support bend at the base and an inspection bend at mid-height of the shaft. Thanks to the predominant use of 2-metre pieces instead of a larger number of shorter sections, the number of push-fit joints along the entire route was reduced by approximately a third compared to a solution made up solely of 0.5 m and 1.0 m pieces.

How to decide between 0.5 / 1.0 / 2.0 m lengths

When compiling a bill of materials for a specific installation, we recommend proceeding from the total measured route height downward: first divide the height into as many 2-metre pieces as possible, then adjust the remaining difference to the exact height using a combination of 1.0 m and 0.5 m pieces (or by cutting the last piece to size with a hand saw). This procedure minimises the number of push-fit joints while maintaining the exact assembly height. When ordering, also take into account the length "consumed" by bends and inspection pieces included in the route – do not count these towards the total straight length twice, as their own overall length is part of the given part's specification. If in doubt about the exact number of pieces, it is always worth having the assembly calculated by an installation company or our customer service before ordering, to avoid having to purchase additional individual pieces after installation has begun.

Typical usage scenarios

You will most often reach for this part when:

• installing a new high-output condensing boiler in an apartment building with a tall, originally masonry chimney shaft,
• replacing an older atmospheric boiler with a condensing one, where the original chimney stops being used for direct discharge and becomes merely a protective casing for the new plastic flue,
• extending or supplementing an existing assembly during a boiler room renovation on a higher floor.

By combining several 2-metre pieces (possibly supplemented with shorter pieces for fine adjustment), it is possible to assemble a discharge for almost any real shaft height common in residential construction.

Compatibility and use within the system

This part belongs to the closed range of original Vaillant accessories for Ø 110 mm shaft flue gas discharge and is intended for combination with other parts of the same range – extensions (0.5 m, 1.0 m and 2.0 m), bends of various angles, inspection pieces, support bends, spacer brackets, fixing clamps and a wall rosette. It is used primarily when installing or replacing high-output Vaillant condensing boilers (ecoTEC exclusiv range, ecoTEC pro/plus in higher output versions, and floor-standing ecoCRAFT exclusiv boilers), as well as corresponding Protherm models (Panther Condens, Tiger Condens, Bizon Condens in higher outputs) – Vaillant and Protherm belong to the same manufacturing group, so parts of the discharge system are commonly identical, however always verify the exact type and connection dimension in the installation manual for your specific boiler.

Before ordering, we recommend having a simple assembly design prepared by our customer service or an installation company according to the height and diameter of your existing shaft – the correct number and combination of parts (length of straight sections, number and angle of bends, number of spacer brackets and fixing clamps) is key to the safe and standard-compliant operation of the entire discharge system.

Shaft flue gas discharge systems of this type are designed and assessed in both Slovakia and the Czech Republic according to the STN EN 1443 (Chimneys – General requirements) and STN EN 14471 (Chimneys – System chimneys with plastic flue liners) standards, which among other things define the designation of the so-called temperature, pressure and resistance classes of components (for example, condensate resistance class "W" – wet operation, typical precisely for condensing boilers). Original Vaillant parts of this range correspond to the relevant classes stated in the manufacturer's documentation and installation manual of the specific boiler with which the system is supplied – this compliance is precisely the reason why it is recommended to use only parts from one closed range for shaft discharge, rather than combining them with products from other manufacturers.

Comparison with shorter extensions in the range

The range of Ø 110 mm straight sections offers three lengths – 0.5 m, 1.0 m and this 2.0 m piece. The shorter pieces (0.5 m and 1.0 m) are suitable for fine adjustment of the assembly to an exact height or for short sections between two bends, while the 2.0 m piece is intended for quickly spanning long straight passages with a minimum of joints. In practice, all three lengths are commonly combined in a single assembly – the longer pieces form the main backbone of the route, while the shorter ones are used to fine-tune the remaining height.

Technical parameters

Maintenance and service inspections

A shaft flue gas discharge made of polypropylene requires little maintenance, but as part of the flue gas path it is subject, just like a masonry chimney, to regular inspection by a chimney sweep according to applicable regulations and intervals set by the boiler manufacturer and local chimney inspection regulations. During inspection, the main things checked are joint tightness, pipe patency (deposits, possible foreign objects), the condition of the sealing rings in the push-fit joints, and the functionality of condensate drainage from the lower part of the system. PP parts are not normally cleaned with aggressive solvents – mechanical removal of deposits and rinsing with water, or a mild detergent, is sufficient.

Condensate produced during condensing boiler operation is mildly acidic (typically in the range of pH approximately 3 to 5, depending on the type of gas burned and the boiler's operating state), which is why the entire system route is designed with a gradient towards the collection point, with condensate being drained either directly into the boiler (where it is usually neutralised or discharged into the sewer via a siphon), or into a separate collection point at the base of the shaft. During regular inspection, therefore, also pay attention to whether the condensate is actually flowing freely and not standing at lower points of the route, which could indicate an incorrect slope or a blockage in some section.

Safety and regulatory notes

A shaft flue gas discharge is subject to the same regulations regarding inspection and cleaning of chimney structures as a classic masonry chimney, since the shaft itself continues to serve as a protective casing around the plastic pipe and as a space for drawing in combustion air. Before commissioning, have the assembly inspected by an authorised chimney sweep and entrust the installation to a company with professional competence for installing gas appliances and flue gas paths.

Why choose the original part

Original Vaillant parts are made of exactly the same material and with the same tolerance dimensions as the boiler's original assembly, guaranteeing 100% compatibility with the rest of the system and preserving the manufacturer's warranty on the flue gas path. With non-original or universal parts, there is a risk not only of problems with the tightness of the push-fit joint, but potentially also issues with warranty recognition or acceptance by a chimney sweep during inspection.