Product detailed description

Vaillant mounting rings (5 pcs), Ø 110 mm

The pack of 5 mounting rings is used to secure a Ø 110 mm flue pipe to the wall of a masonry shaft at regular height intervals. While spacer holders centre the pipe within the cross-section of the shaft, mounting rings secure it against vertical movement and sagging along the entire length of the route.

Vaillant LAS Ø 110 mm shaft flue gas system

This component is part of the original Vaillant shaft flue gas system (abbreviated LAS – from the German "Luft-Abgas-System"), used with high-capacity condensing boilers (typically the higher output ranges of ecoTEC exclusiv/pro/plus and the floor-standing ecoCRAFT exclusiv boilers, as well as equivalent 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 carries flue gases through a single-wall pipe with a diameter of 110 mm inside an existing structural 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 the flue 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 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.

Difference from spacer holders

A spacer holder keeps the pipe in the centre of the shaft's cross-section, but on its own it does not necessarily bear significant load or prevent slight vertical movement of the pipe due to thermal expansion. A mounting ring, on the other hand, directly secures the pipe to the shaft wall – holding it against sideways deflection and sagging between the individual support points, while the ring's design is usually made to still allow the pipe slight longitudinal (thermal) movement, thus preventing stress build-up as the system heats up and cools down.

Combining both types of accessories – spacer holders and mounting rings – achieves a stable yet expansion-friendly position of the entire pipe assembly along the whole height of the shaft.

Ring installation

The ring is fixed to the shaft wall using anchoring material suitable for the given masonry (screws with anchors) and is then closed around the pipe so that it holds it without excessive tightening, which would prevent its free thermal expansion. The spacing of the rings along the height of the shaft is specified in the installation manual of the specific boiler – generally, for longer straight sections (for example when using 2-metre extensions), it is advisable to have at least one ring per length of each such section.

Step-by-step installation procedure

1. According to the boiler's installation manual, determine the required spacing of mounting rings along the height of the assembly.
2. Anchor the ring to the shaft wall at the given point using suitable anchoring material matching the wall material.
3. Close the ring around the pipe so that it holds it without excessive tightening that would prevent its free thermal expansion.
4. Check that the pipe can move slightly lengthwise within the ring, but without excessive lateral deflection.
5. Repeat the procedure for each additional ring in the pack according to the specified spacing.
6. Once all rings are fitted, visually verify that the straight section between support points shows no visible sagging.

Practical example

For an assembly with two 2-metre extensions in a row (a total of 4 metres without an intermediate elbow), one mounting ring was fitted in the middle of each of these sections, meaning two rings from a single pack were used for this particular section of the assembly, with the remaining three pieces used further up the route at other straight sections. As a result, none of the long straight sections were left without ongoing support, avoiding the risk of long-term sagging.

How to calculate the required number of packs

As with spacer holders, the number of mounting rings needed should be derived from the recommended spacing given in the boiler's installation manual and the total height of the assembly. For shorter assemblies (up to approximately 3–4 metres), one pack of 5 pieces is usually sufficient, while for taller, multi-storey routes the pack needs to be ordered repeatedly. We also recommend allowing for rings on short horizontal sections at the boiler connection, not just on the main vertical part in the shaft, as these may also require ongoing support depending on the boiler room layout.

When you need this pack

Mounting rings are needed for every vertical installation of a shaft flue longer than one standard storey – they prevent the pipe from sagging between support points under its own weight or the weight of condensate, and reduce the risk of leaks at the push-fit joints caused by long-term sagging.

Compatibility and use within the system

This component belongs to the closed range of original Vaillant accessories for the Ø 110 mm shaft flue system and is intended for combination with other components of 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 rings and a wall rosette. It is used mainly when installing or replacing high-capacity Vaillant condensing boilers (ecoTEC exclusiv range, ecoTEC pro/plus in higher output versions, and the 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 flue system are commonly identical, however always verify the exact type and size of the connection in the installation manual of the specific boiler.

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

Shaft flue gas 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 class of components (for example, resistance class to condensate "W" – wet operation, typical precisely for condensing boilers). Original Vaillant components in 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 – it is precisely this compliance that is the reason why, for shaft flue systems, it is recommended to use only components from a single closed range instead of combining them with products from other manufacturers.

Comparison with spacer holders

As mentioned above, the mounting ring secures the pipe to the shaft wall against sagging, while the spacer holder centres it within the cross-section of the shaft – these are two different, mutually complementary functions that are commonly combined along the whole height of the route in a real assembly.

Technical parameters

Maintenance and service inspections

The polypropylene shaft flue system is low-maintenance, but as part of the flue gas path it is, like a masonry chimney, subject to regular inspection by a chimney sweep according to applicable regulations and the intervals set by the boiler manufacturer and local chimney inspection ordinance. During inspection, particular attention is paid to the tightness of joints, the patency of the pipe (deposits, possible foreign objects), the condition of the sealing rings at the push-fit joints, and the functionality of condensate drainage from the lower part of the system. Components made of PP are usually 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 within a pH range of approximately 3 to 5, depending on the type of gas burned and the boiler's operating state), which is why the entire route of the system is designed with a slope towards the collection point and with condensate drainage either directly into the boiler (where it is usually neutralised or drained into the sewage system via a siphon), or into a separate collection point at the base of the shaft. During regular inspections, therefore, also pay attention to whether the condensate actually flows away 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

The absence or insufficient number of mounting rings increases the risk of long-term sagging of the pipe and subsequent stress on the push-fit joints, which can lead to leaks in the flue gas path – we therefore recommend strictly following the spacing specified in the boiler's installation manual and, in case of doubt, consulting an installation company.

Why ongoing support should not be omitted

Without regular support, a longer vertical section of the flue would be exposed to sagging under its own weight, which in the long run increases stress on the push-fit joints and the risk of leaks. Mounting rings are therefore a standard, not optional, part of every longer assembly.