Vaillant Elbow 15°, Ø 160 mm

Product detailed description

Elbow 15° Ø 160 mm – the gentlest direction correction in the entire range

The 15° elbow is the gentlest fitting in the whole family of Ø 160 mm elbows (87°/45°/30°/15°) and is used where the pipe route needs only a minimal deflection – for example when fine-tuning the axis between two almost parallel sections, compensating for inaccuracy in a structural opening for the duct passage, or in combination with another 15° elbow to create a very smooth, almost imperceptible lateral shift of the route with minimal flow resistance.

In terms of flue gas flow, this fitting has the lowest resistance coefficient in the entire range of elbows of this diameter – using it instead of a sharper elbow (where the route layout allows it) slightly reduces the overall draught requirements of the flue system, which can be decisive especially in longer or higher-output cascade installations.

Flue gas exhaust systems for Vaillant cascade boiler rooms

When a single condensing boiler cannot cover the heat demand of a building – an apartment building, hotel, industrial hall, office building or a larger technological boiler room – the solution is usually not one large boiler, but a cascade of several smaller or medium-output Vaillant condensing boilers connected in parallel. The advantage of a cascade solution is higher operational reliability (a failure of one boiler does not mean a heating outage for the whole building), better output control according to current demand (the number of running boilers and the output of each can be modulated), and easier future expansion of the boiler room with another boiler if heat demand increases.

Each boiler in the cascade has its own connection for flue gas exhaust and combustion air intake, but for practical, economic and structural reasons, the flue gases of all boilers are usually led away through one common collective flue duct (collector) into a single chimney or through a single roof/facade duct passage. This is exactly the purpose of the range of components described below – these are parts of a separate (not concentric) flue gas exhaust system with a diameter of 160 mm or 200 mm, which connect to the outlets of the individual boilers and join them into one common pipe.

The system is modular – it consists of basic connection sets (for the first two boilers of the cascade, including the necessary fitting for condensate drainage), extension sets (for each additional boiler added to the cascade), separate elbows of various angles for bypassing obstacles and changing the direction of the route, extensions of various lengths to bridge the distance between the boilers and the riser, and finally a set for connecting the whole assembly to a masonry chimney shaft.

Typical placement in the assembly

The 15° Ø 160 mm elbow is used in practice mainly in combination of two pieces to create a smooth parallel shift of the route (the so-called "offset") over a smaller distance, or individually where the pipe axis only needs to be slightly fine-tuned – for example when connecting to an existing structural opening in a wall or ceiling whose position slightly differs from the originally designed route axis.

The part is fully compatible with the other components of the Ø 160 mm range and connects using an identical socket joint with a sealing ring.

Material and construction – why polypropylene (PP)

All parts in this range are made of polypropylene (PP) – a plastic used in the flue gas exhaust systems of condensing boilers precisely because it perfectly resists the chemically aggressive condensate that naturally forms during the operation of condensing technology. Compared to a classic (non-condensing) boiler, a condensing boiler also uses the latent heat contained in the water vapour of the flue gases – this vapour cools below the dew point in the flue gas heat exchanger and condenses, producing a condensate that is mildly acidic (pH approximately 3–5, depending on the fuel type and operating conditions). Metal (e.g. stainless steel) flue ducts can also withstand this load, but plastic PP systems are lighter to handle, faster to install thanks to sealing-ring joints without the need for welding or special tools, and, at comparable quality, are usually also more cost-effective.

The operating temperature of flue gases in condensing boilers is relatively low (roughly up to approx. 80–120 °C, depending on the operating mode and boiler output) – this is exactly why using a plastic PP pipe instead of a classic metal flue duct (common, for example, with older atmospheric or low-temperature boilers) is not only possible but, in terms of condensate resistance, also more suitable. The system is certified and dimensioned by the manufacturer directly for cooperation with Vaillant condensing boilers of the corresponding output range and connection type.

The joints between individual parts are made by socket insertion with a rubber sealing ring (so-called socket joint) – this design allows simple, tight and at the same time demountable assembly without gluing or welding, which greatly simplifies any future route modifications, replacement of a damaged part, or expansion of the cascade with another boiler.

Practical example

When installing a vertical riser of a cascade flue duct, it sometimes turns out that the actual position of the structural passage through the ceiling differs by a few centimetres from the originally designed axis of the pipe leading from the boilers. Instead of complicated relocation of the whole route, it is enough to use two 15° elbows one right after the other (with a short extension between them) – these smoothly, almost imperceptibly deflect the route by exactly the required distance, while the added flow resistance is minimal thanks to the small angle.

Comparison of elbow angles within the Ø 160 mm range

The 15° elbow is the gentlest member of the entire family of fittings (87°/45°/30°/15°) and is used where even a 30° elbow would represent an unnecessarily large change of direction. In combination with a short extension, a pair of 15° elbows can resolve even relatively small deviations of the route axis, which would otherwise have to be dealt with by inaccurate, improvised bending or by tolerating misalignment of the joint – which is not desirable with socket joints using sealing rings.

Ordering: Since this is the gentlest angle available, when ordering we recommend considering whether this elbow would be sufficient for the given direction change instead of an elbow with a more pronounced angle (30°, 45° or 87°) – this will save on the overall resistance of the route.

Assembly and installation

The installation of a flue gas exhaust system for gas appliances (including cascade boiler rooms) in Slovakia is subject to the requirements of the standards STN EN 1443 (Chimneys), STN 73 4201 (Chimneys and flue ducts) and related gas industry technical rules (TPP), and must be carried out by an authorised and professionally qualified person – an authorised service technician or installation company with the relevant authorisation to install gas appliances and their exhaust systems. Commissioning of the boiler room also includes an inspection of the chimney/flue duct carried out by a chimney sweeping company and the issuance of the relevant inspection report.

When designing the route of a cascade flue duct, it is necessary to take into account in particular: the total rated heat output of all boilers in the cascade (this determines the required diameter of the collective pipe – 160 mm or 200 mm), the maximum permissible length of the route and the number of elbows (the manufacturer specifies equivalent lengths for individual fittings), the slope of horizontal sections back towards the boiler or condensate separator (usually at least 3° so that condensate can drain by gravity and does not remain standing in the pipe), sufficient fastening of the pipe with spacer brackets at regular intervals (typically every 1–1.5 m) to prevent sagging or excessive stress on the socket joints, and maintaining access to inspection openings and inspection elbows for regular cleaning and inspection of patency.

When cascading several boilers into one collective pipe, it is also essential to respect the order and direction of connection of the individual branches according to the manufacturer's installation instructions (including the recommended use of check valves in cascades with three or more boilers, so that when one boiler is shut down, flue gases from the running boilers do not flow back into the shut-down unit) and to maintain the prescribed minimum incline and direction towards the common chimney or facade/roof outlet.

Care of the elbow during operation

In terms of flue gas flow, the 15° elbow is the smoothest fitting in the entire range, so the risk of dirt accumulating inside it is also the lowest. It is checked indirectly, as part of the regular annual inspection of the route through the nearest accessible inspection point, just like the other "non-inspection" elbows in the assembly.

Storage and handling before installation

The 15° elbow is the least "prominent" part of the range, and during handling it is sometimes easy to forget to pay it the same attention as more pronounced fittings – nevertheless, the same principle applies as with other PP parts: store in a dry environment before installation, protect from direct sunlight and mechanical damage to the sealing ring in the socket. We also recommend, when ordering a larger number of pieces (for example for several fine route correction points at once), considering a small extra reserve in case of damage during installation.

Service, cleaning and service life

Regular inspection and cleaning of the flue gas exhaust system is part of the standard annual service inspection of a condensing boiler room. Thanks to the inspection openings and inspection elbows in the assembly, individual sections of the pipe can be checked and, if necessary, cleaned (e.g. of any deposits) without having to completely dismantle the whole route. The condensate separator, if included in the assembly, needs to be checked regularly and, if necessary, emptied/flushed to prevent it from clogging and condensate backing up into the pipe.

The service life of a quality PP exhaust system from the manufacturer, directly compatible with the given boiler range, is comparable to the service life of the boiler itself when properly installed and regularly serviced – i.e. roughly 15 or more years of operation. When replacing or adding individual parts in the future (for example when expanding the cascade with another boiler), it is advisable to use original components from the same manufacturer and diameter, in order to maintain full compatibility of the joints and the validity of the warranty on the entire exhaust system.

Frequently asked questions

Why buy this Vaillant accessory at ATRIA.SK

The 15° Ø 160 mm elbow is the ideal solution for fine, almost invisible corrections of the flue duct route direction – where sharper elbows would represent an unnecessarily large intervention in the pipe's course.

When purchasing any part of the exhaust system, we are happy to advise you on choosing the right combination of components for your specific boiler room – just contact us with details about the type and number of boilers, or with project documentation. We usually dispatch goods within 24–48 hours of ordering, and for larger assemblies we will inform you in advance of the delivery date if necessary.