Product detailed description

Vaillant spacer holder (10 pcs), Ø 110 mm, for shaft 40 × 40 cm

A package of 10 spacer holders is used to precisely center the Ø 110 mm flue pipe within the cross-section of a masonry shaft with an internal size of up to 40 × 40 cm. This is an inconspicuous but functionally key component of the whole LAS shaft system – correct centering of the pipe determines whether sufficient and even free space is maintained around it across the whole shaft cross-section, which is needed for drawing combustion air to the boiler.

Vaillant LAS Ø 110 mm flue gas shaft system

This part is a component of the original Vaillant flue gas shaft exhaust system (abbreviated LAS – from the German "Luft-Abgas-System"), used with large-capacity condensing boilers (typically the higher-output ecoTEC exclusiv/pro/plus ranges and the ecoCRAFT exclusiv floor-standing 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 exhaust gases through a single-wall pipe with a diameter of 110 mm through 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 façade or roof in addition to the existing shaft, and in multi-storey buildings it allows the exhaust to be routed to the required height without the need to build a new chimney. All system components are made of durable polypropylene (PP), which withstands long-term contact with the mildly acidic condensate produced during the operation of a condensing boiler, and are joined by a simple socket-to-socket plug-in system with an integrated sealing ring, without the need for gluing or additional sealing.

Why centering the pipe in the shaft is so important

The principle of the shaft (LAS) system is that exhaust gases leave through a single-wall Ø 110 mm pipe, while the boiler draws combustion air from the free space of the shaft around this pipe. If the pipe were positioned off-center within the shaft cross-section (for example, resting against one wall), an excessive cross-section would form on one side while an insufficient one would form on the other for the incoming air flow – in extreme cases this can lead to an insufficient air supply for combustion. Spacer holders therefore keep the pipe precisely centered at regular intervals along the entire height of the shaft.

The package of 10 pieces is sized to cover the typical height of one assembly at the recommended holder spacing; check the exact number required for the height of your specific building in the boiler's installation manual or with your installation company – for very tall shafts it may be necessary to order the package more than once.

Installing the holders

The holder is fitted directly onto the pipe's outer surface at a socket joint or on a straight section, with its arms resting against the inner walls of the shaft, keeping the pipe centered in the cross-section. For shafts with dimensions close to the stated maximum (40 × 40 cm), make sure the holder's arms rest evenly against all four walls – with an irregular masonry shaft cross-section, slight adjustment or additional backing material may be needed.

Step-by-step installation procedure

1. Determine the required spacer holder spacing along the height of the shaft according to the boiler's installation manual.
2. Fit the holder onto the pipe's outer surface at the planned position, most often near a socket joint or in the middle of a longer straight section.
3. Rest the holder's arms evenly against all four inner walls of the shaft so that the pipe remains precisely centered in the cross-section.
4. For an irregular masonry shaft cross-section, add backing material under the arms if needed for even contact.
5. Repeat the procedure for each additional holder in the package according to the set spacing, along the entire height of the assembly.
6. After installing all holders, visually verify that the pipe is indeed centered along the entire height, with no visible contact with the shaft wall.

Practical example

During installation in a masonry shaft with an internal size of approximately 38 × 38 cm (just below the 40 × 40 cm maximum for which this package is intended), six spacer holders from one package were installed at a height of 8 meters at regular intervals according to the boiler's installation manual, with the remaining four pieces kept as a reserve for possible future adjustments or replacement of a damaged piece. Thanks to correct centering of the pipe at all measured heights, an even free space required for combustion air intake was maintained around the entire circumference.

How to calculate the required number of packages

To calculate the required number of spacer holders, use the recommended spacing stated in your specific boiler's installation manual and the actual height of the shaft. For example, with a recommended spacing of approximately once every 2 meters and a total assembly height of 8 meters, you would need approximately 4–5 pieces, i.e. less than one package of 10 pieces; for a taller assembly (for example 16–18 meters), it may be necessary to order the package twice. It is always better to have a few pieces in reserve than to be exactly at the required number, since minor position adjustments during installation (working around an uneven shaft wall) may require an extra holder beyond the original calculation.

When this package is needed

Spacer holders are required for every installation of a Ø 110 mm shaft flue system without exception – they are not optional accessories but a functional part of the combustion air intake system. This particular package is intended for shafts with an internal size of up to 40 × 40 cm; for larger or unusual shaft cross-sections, we recommend checking suitability with your installation company, or considering a different type of centering accessory.

Compatibility and use in the system

This part belongs to the closed range of original Vaillant accessories for Ø 110 mm shaft flue exhaust and is intended for combination with other parts from the same range – extensions (0.5 m, 1.0 m and 2.0 m), elbows of various angles, inspection pieces, a support elbow, spacer holders, mounting bands and a wall rosette. It is used primarily when installing or replacing large-capacity Vaillant condensing boilers (the ecoTEC exclusiv range, higher-output versions of ecoTEC pro/plus, and ecoCRAFT exclusiv floor-standing 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 exhaust system are commonly interchangeable; however, always check the exact type and connection size in the installation manual for your specific boiler.

Before ordering, we recommend having our customer service or your installation company prepare a simple assembly design based on the height and diameter of your existing shaft – the correct number and combination of parts (length of straight sections, number and angle of elbows, number of spacer holders and mounting bands) is key to safe and compliant operation of the entire exhaust system.

Shaft flue exhaust systems of this type are designed and assessed in 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) series of standards, which, among other things, define the designation of the temperature, pressure and resistance classes of components (for example, condensate resistance class "W" – wet, i.e. wet operation typical of condensing boilers). Original Vaillant parts of this range correspond to the relevant classes stated in the manufacturer's documentation and the installation manual of the specific boiler with which the system is supplied – this compliance is precisely why it is recommended to use only parts from a single closed range in a shaft exhaust system, rather than combining them with products from other manufacturers.

Comparison with mounting bands

Spacer holders and mounting bands complement each other in an assembly, but serve different functions – the holder centers the pipe within the shaft cross-section for even air intake, while the band fixes the pipe to the wall against sagging. In practice, it is common to use both types of parts in combination along the height of the same assembly.

Technical parameters

Maintenance and service checks

The polypropylene shaft flue exhaust system is undemanding in terms of maintenance, but as part of the flue gas path it is, like a masonry chimney, subject to regular inspection by a chimney sweep in accordance with applicable regulations and the intervals set by the boiler manufacturer and local chimney inspection regulations. During inspection, the tightness of joints, the pipe's passability (deposits, possible foreign objects), the condition of the sealing rings in the plug-in joints, and the functionality of condensate drainage from the lower part of the system are checked in particular. Parts made of PP are generally not cleaned with aggressive solvents – mechanical removal of deposits and rinsing with water, or a mild detergent, is sufficient.

The condensate produced during condensing boiler operation is mildly acidic (typically in the pH range of approximately 3 to 5, depending on the type of gas burned and the boiler's operating state), so the entire system route is designed with a gradient towards a collection point, with condensate drained either directly into the boiler (where it is usually neutralized 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 actually flows freely and does not remain standing at lower points of the route, which could indicate an incorrect slope or a blockage in some section.

Safety and regulatory notes

Insufficient or incorrect centering of the pipe in the shaft can negatively affect the evenness of combustion air intake to the boiler, which is an important factor for the safe and efficient operation of a condensing boiler – we therefore recommend strictly following the holder spacing specified in the installation manual.

Why not to underestimate pipe centering

This is an inexpensive and simple part, but its function is directly linked to a sufficient supply of combustion air to the boiler – omitting or incorrectly positioning the holders can affect the correct and safe operation of the whole system, so we do not recommend bypassing it or replacing it with makeshift solutions.