Product detailed description

Vaillant elbow 15°, Ø 110 mm

The elbow with a 15° bend is the least pronounced angular component in the Ø 110 mm shaft flue range – it is used for fine-tuning the route direction where only a minimal deviation from a straight line is needed. The part has an actual weight of 1.35 kg and, like the rest of the range, is made of polypropylene resistant to flue gas condensate.

Vaillant LAS Ø 110 mm shaft flue gas exhaust system

This component is part of the original Vaillant shaft flue gas exhaust system (abbreviated LAS – from the German "Luft-Abgas-System"), used with high-capacity condensing boilers (typically higher-output ecoTEC exclusiv/pro/plus ranges and ecoCRAFT exclusiv floor-standing boilers, as well as equivalent Protherm models from the same manufacturing group). Unlike the common concentric flue (pipe within a pipe) used with small wall-mounted boilers, the shaft system routes flue gas 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 requires no new facade or roof penetration 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 components of the system are made of durable polypropylene (PP), which withstands long-term contact with the mildly acidic condensate produced during 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.

When 15° is enough and more is not needed

When designing a shaft flue route, the aim is to keep the pipe as straight as possible – every degree of deviation causes a slight increase in flue gas flow resistance and potentially a slightly more complicated installation. The 15° elbow is therefore used exclusively for fine corrections: for example, when the axis of a masonry shaft is not perfectly vertical, when a small irregularity in the wall needs to be bypassed, or when the connection angle between two otherwise straight sections needs slight adjustment.

Where a more significant change of direction is needed (bypassing a beam, a more pronounced deviation towards the boiler position), an elbow with a larger angle – 30° or 45° – or a combination of several elbows is used instead.

Installation and orientation

The elbow is inserted using the same push-fit joint as the other components in the range; its bend axis can be rotated during installation by 360° around the longitudinal axis of the pipe, so the direction of the 15° deviation can be aimed exactly where the route design requires. Once inserted, the elbow's position can no longer be changed, so verify the orientation before final securing of the assembly.

Step-by-step installation procedure

1. Identify the exact point in the route where a fine correction of direction is needed (for example, a slight deviation of the shaft axis from vertical).
2. Before inserting, rotate the elbow around the longitudinal axis of the pipe so that the direction of the 15° deviation matches the actual need of the route.
3. Lightly apply suitable lubricant for plastic systems to the sealing ring.
4. Insert the elbow fully into the socket of the adjacent component and connect the continuation of the route to its other end.
5. Visually verify that the selected angle has been maintained after insertion and that no unintentional rotation has occurred.

Practical example

During installation into an older masonry shaft whose axis deviated slightly from vertical in the upper third (a result of a minor construction inaccuracy during the original chimney build), a single 15° elbow was used exactly at the point where the deviation occurred, instead of a more significant intervention in the route. This small correction was enough for the rest of the assembly to continue without further complications all the way to the outlet, without needing a larger angle or additional modification of the masonry shaft structure itself.

How to choose the right elbow angle from the whole range

The range offers elbows of 15°, 30°, 45° and 87° (including inspection and support elbows) – the general rule when designing a route is to always use the smallest angle that actually solves the given situation, since a smaller deviation means more favourable flue gas flow and simpler installation. Therefore, always consider the 15° elbow first for any minor direction correction – only when you find that this smallest angle is not sufficient for the required deviation should you move to 30° or, if needed, 45°. A practical guideline is to hold a straight edge or laser against the planned route directly at the installation site and measure the actual required deviation, rather than estimating by eye.

As this is the smallest and also the most frequently reordered angle for additional corrections to an already partially assembled system, we recommend keeping one or two extra pieces in reserve for larger installations, beyond the original calculation – their cost is low compared to a possible delay in installation caused by the need to order a single missing piece afterwards.

Typical points of use in the assembly

• compensating for a slight deviation of the actual axis of a masonry shaft from vertical,
• minor correction when connecting to original structural penetrations between floors,
• fine adjustment of direction just before connecting to the lower support or inspection elbow.

Compatibility and use within the system

This component belongs to the closed range of original Vaillant accessories for Ø 110 mm shaft flue gas exhaust 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 brackets, fixing clamps and a wall rosette. It is used primarily when installing or replacing high-capacity Vaillant condensing boilers (ecoTEC exclusiv range, higher-output ecoTEC pro/plus versions and ecoCRAFT exclusiv floor-standing boilers), as well as with 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, but always verify the exact type and connection size in the installation manual for the 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 components (length of straight sections, number and angle of elbows, number of spacer brackets and fixing clamps) is key to safe and 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) standards, which, among other things, define the designation of the temperature, pressure and resistance class of components (for example, resistance class "W" – wet operation, typical precisely for condensing boilers). Original Vaillant components in this range correspond to the relevant classes stated in the manufacturing documentation and installation manual of the specific boiler with which the system is supplied – this compliance is exactly why it is recommended to use only components from a single closed range for shaft flue exhaust systems, rather than combining them with products from other manufacturers.

Comparison with 30° and 45° elbows

Within the range of Ø 110 mm angular components, this is the smallest available angle – where a 30° or 45° elbow already represents a noticeable deviation of the route, the 15° elbow serves purely for fine adjustment. When designing an assembly, it is advisable to first check whether this smallest angle is sufficient before reaching for a more significant solution that would deviate the route more than is actually needed at that point.

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, just 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, particular attention is paid to the tightness of joints, the clearance of the pipe (deposits, possible foreign objects), the condition of the sealing rings in the push-fit joints, and the proper functioning of condensate drainage from the lower part of the system. PP components are typically not cleaned with aggressive solvents – mechanical removal of deposits and rinsing with water, or a mild detergent, is sufficient.

The condensate produced during operation of a condensing boiler is mildly acidic (typically in the pH range of approximately 3 to 5, depending on the type of gas burned and the operating state of the boiler), so the entire route of the system is designed with a gradient towards the collection point and condensate drainage either directly into the boiler (where it is usually neutralised or discharged into the sewage system via a siphon), or into a separate collection point at the base of the shaft. During regular inspection, therefore, also check that 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 notes

This is a common, non-load-bearing component without specific safety risks beyond standard flue gas path installation principles – correct insertion and orientation within the overall route design are all that matters.

Why it is worth having the smallest angle available too

Many real shafts are not perfectly straight, and it is precisely the smallest available 15° angle that allows the route to be fine-tuned without an unnecessarily large deviation that would otherwise result from using a 30° or 45° elbow where only a fraction of that correction is needed.