Product detailed description

Vaillant support elbow 87° with 350 mm mounting strip, Ø 110 mm

The support elbow 87° with a mounting strip 350 mm long is the only part in the entire Ø 110 mm shaft flue assembly that is structurally designed to bear the weight of the entire vertical column of pipes and elbows above it. Unlike ordinary elbows (15°, 30°, 45° and the inspection 87°), which only change the direction of flue gas flow and are suspended on surrounding parts, this elbow has an integrated mounting strip that is anchored directly to the wall or bottom of the shaft, thus taking on the load from the parts positioned above.

Vaillant LAS Ø 110 mm shaft flue gas exhaust system

This part is a component of the original Vaillant shaft flue gas exhaust system (abbreviated LAS – from the German "Luft-Abgas-System"), which is used with high-capacity condensing boilers (typically higher output series ecoTEC exclusiv/pro/plus and the floor-standing boilers ecoCRAFT exclusiv, as well as equivalent output models from Protherm within 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 commonly an older masonry chimney no longer used for its original purpose), and combustion air is drawn in from 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 flue to be routed to the required height without the need to build a new chimney. All parts of the system are made of durable polypropylene (PP), which withstands long-term contact with the slightly acidic condensate generated during the operation of a condensing boiler, 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 the load-bearing function is important

A vertical shaft can carry a flue several storeys high – the combined weight of all pipes, elbows and condensate in the system is not negligible. If this weight were to rest solely on the push-fit joints of individual parts, over time they could stretch, become leaky, or even fail completely. The support elbow therefore addresses the change of direction from vertical to horizontal (typically at the transition from the shaft towards the boiler) and at the same time serves as a solid foundation anchored into the building structure, on which the entire assembly above it actually rests.

The 350 mm long mounting strip provides sufficient surface for anchoring with multiple anchoring screws into the masonry or load-bearing structure of the shaft, distributing the load evenly instead of concentrating it at a single point.

Principles of correct installation

The support elbow is always installed at a definitive, structurally suitable position at the bottom or lower part of the shaft – its position practically no longer changes once further parts are connected, so before anchoring it is necessary to verify the correct height, the orientation of the outlet towards the boiler, and the horizontal alignment of the strip. The anchoring material (type of anchors and screws) is selected according to the material of the shaft wall (brick, concrete, masonry) so that it can bear the actual weight of the entire planned assembly, including a safety margin.

After anchoring the strip, the rest of the assembly is connected to the elbow using the standard push-fit joint, upward (extensions, further elbows, inspection pieces) and outward, usually a short horizontal section for connection to the boiler.

Step-by-step installation procedure

1. According to the route design, determine the exact height and directional position of the support elbow at the bottom or lower part of the shaft.
2. Check the material of the shaft wall (brick, concrete, masonry) and select the corresponding anchoring material (screws, anchors) with sufficient load capacity for the planned weight of the entire assembly.
3. Anchor the 350 mm long mounting strip to the wall in a horizontal position, with anchoring points evenly distributed along the entire length of the strip.
4. Verify the strength of the anchoring before connecting further parts of the assembly.
5. Connect the remaining parts to the elbow, both upward (extensions, elbows, inspection pieces) and towards the connection to the boiler.
6. After completing the entire assembly, check that the weight actually rests on the anchored elbow and not on the surrounding push-fit joints.

Practical example

During the installation of an ecoCRAFT exclusiv floor-standing condensing boiler in a boiler room in the basement of a family house with a masonry shaft approximately 9 metres high, the 87° support elbow with mounting strip was anchored into the load-bearing brick wall just above the boiler connection level, using four anchoring screws with anchors distributed along the entire 350 mm length of the strip. The entire weight of nine metres of pipes, two elbows and one inspection piece above it then rested on the elbow anchored in this way – without this load-bearing point, the entire load would rest on the push-fit joints, which the manufacturer and the local chimney sweep both clearly excluded as an unacceptable solution.

How to correctly plan the position of the support elbow

When designing the assembly, first determine where in the lower part of the shaft the direction actually changes from vertical to horizontal towards the boiler – this location is the natural position for the support elbow. Then check the material and thickness of the shaft wall at that point, since the choice of anchoring material depends on it. If the layout of the boiler room does not allow a short horizontal section to be routed directly from the elbow to the boiler, it may be necessary to add one or two more elbows with a smaller angle (30° or 45°) to complete the connection. We recommend having the final position and anchoring method assessed on site by an installation company, as this is the structurally most critical point of the entire installation.

When you absolutely need this part

The support elbow is a mandatory component of practically every vertical Ø 110 mm shaft assembly longer than one standard storey – without it, the entire weight of the flue would rest solely on the push-fit joints, which neither the manufacturer nor any standard permits. It is generally installed once per assembly, at its lowest point.

Compatibility and use in the system

This part belongs to the closed range of original Vaillant accessories for the Ø 110 mm shaft flue gas exhaust and is intended for combination with other parts of the same range – extensions (0.5 m, 1.0 m and 2.0 m), elbows of various angles, inspection pieces, the support elbow, spacer holders, fixing collars and a wall rosette. It is used mainly during the installation or replacement of high-capacity Vaillant condensing boilers (ecoTEC exclusiv series, ecoTEC pro/plus in higher output versions, 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 verify the exact type and connection size in the installation manual for 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 parts (length of straight sections, number and angle of elbows, number of spacer holders and fixing collars) is key to safe and standard-compliant operation of the entire exhaust system.

Shaft flue gas exhaust 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) series of standards, which, among other things, also 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 parts of this range comply with 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, for shaft flue exhaust systems, it is recommended to use exclusively parts from one closed range instead of combining them with products from other manufacturers.

Comparison with the 87° inspection elbow

Visually, this is a similar bend angle to the 87° inspection elbow, but functionally the parts are fundamentally different: the support elbow has a mounting strip and bears the weight of the assembly, while the inspection elbow, on the other hand, offers an inspection opening but no load-bearing function. In a typical assembly, the support elbow is used exactly once, at the lowest point of the route, while the inspection elbow can be used several times higher up along the route as needed for inspection access.

Technical parameters

Maintenance and service inspections

The polypropylene shaft flue gas exhaust system is undemanding in terms of maintenance, but as part of the flue gas path it is subject, like a masonry chimney, 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 main checks are the tightness of the joints, the clearness of the pipe (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. Parts made of PP are not normally cleaned with aggressive solvents – mechanical removal of deposits and rinsing with water, or a mild detergent, is sufficient.

The condensate generated during the operation of a condensing boiler is slightly acidic (typically in the range of pH approximately 3 to 5, depending on the type of gas being burned and the operating condition of the boiler), so the entire route of the system is designed with a slope towards a collection point and condensate drainage either directly into the boiler (where it is generally neutralised or discharged into the sewage system via a trap), 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 away 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

This is the structurally most important part of the entire assembly – improper anchoring or the use of unsuitable anchoring material can endanger the stability of the entire flue gas exhaust system. Anchoring should therefore always be entrusted to a professionally qualified installation company that will take into account the actual load capacity of the specific shaft wall.

Why not to save money on the load-bearing part

This is the most safety-critical part of the entire assembly – its failure would jeopardise the stability of the entire flue gas exhaust system. The original Vaillant part has a verified load capacity corresponding to the actual weight of a compatible assembly, which is not guaranteed with unverified substitutes.