Vaillant Elbow 87°, Ø 160 mm

Product detailed description

Elbow 87° Ø 160 mm – basic fitting for changing route direction

The elbow with an angle of 87° is the most common fitting for changing the direction of the collective flue gas duct of a cascade boiler room where a transition from horizontal routing (for example, under the ceiling of the plant room) to a vertical section towards the chimney is needed, or vice versa. The angle of 87° instead of a mathematically exact right angle of 90° is not accidental – the slightly deviated angle improves the natural drainage of condensate in the direction of the prescribed pipe slope and reduces the risk of it being retained directly at the bend, which is essential for long-term trouble-free operation given that condensing boilers produce condensing flue gases all year round.

This is the simplest, "non-inspection" variant of the elbow – without a built-in inspection opening. Where it is appropriate to have the possibility of regular visual inspection and cleaning at a given point of the route, an 87° inspection elbow (order no. 0020095554) is used instead, with the same angle but additionally with a lockable inspection opening.

Flue gas exhaust systems for Vaillant cascade boiler rooms

When a single condensing boiler is not sufficient to cover the heat demand of a building – an apartment building, hotel, operational hall, office building or a larger technological boiler room – this is usually solved not with one large boiler, but with 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 regulation according to current demand (the number of running boilers and the output of each of them is modulated), and easier future expandability of the boiler room with another boiler if heat demand increases.

Each boiler in the cascade has its own flue gas exhaust and combustion air intake port, but for practical, economic and structural reasons, the flue gases of all boilers are usually led out through one common collective flue gas duct (collector) into a single chimney or through a single roof/facade penetration. This is precisely the purpose of the range of components described below – these are parts of a separated (not concentric) flue gas exhaust system with a diameter of 160 mm or 200 mm, which connects to the ports of individual boilers and joins 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 fitting needed for condensate drainage), extension sets (for each additional boiler added to the cascade), individual elbows of various angles for bypassing obstacles and changing route direction, extensions of various lengths for bridging the distance between the boilers and the riser, and finally a set for connecting the whole assembly to a masonry chimney shaft.

Use in a cascade boiler room assembly

The 87° Ø 160 mm elbow is used in practice wherever the boiler room design requires a near-right-angle change of route direction, but the given location is not designated as a main inspection point (that is usually addressed separately, using an inspection elbow or a straight piece with an inspection opening). Typically, these are elbows at the outlet from the boiler port, when bypassing structural elements (beams, pipe routes of other media), or when connecting a horizontal branch to a vertical riser in places where another inspection point is in close proximity.

The part is connected using the same socket joint with a sealing ring as other components of the Ø 160 mm range, so it can be freely combined with extensions of various lengths, other elbows (45°, 30°, 15°), and with basic and extension sets for the cascade.

Material and construction – why polypropylene (PP)

All parts of 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 arises during the operation of condensing technology. A condensing boiler, unlike a classic (non-condensing) boiler, also utilizes the latent heat contained in the water vapor of the flue gases – this is cooled below the dew point in the flue gas exchanger and condenses, with the resulting condensate being slightly acidic (pH approximately 3–5, depending on the type of fuel and operating conditions). Metal (e.g. stainless steel) flue ducts can also withstand this load, but plastic PP systems are lighter to handle, quicker to install thanks to sealing ring joints without the need for welding or special tools, and, at comparable quality, usually also more cost-effective.

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

Joints between individual parts are made with a socket connection with a rubber sealing ring (so-called socket joint) – this construction allows simple, tight, and at the same time detachable installation 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

In a boiler room with two boilers installed back to back, the flue gases from the individual boilers are joined into a common collecting piece and then led to a vertical riser. If the route between the collecting piece and the riser runs under a ceiling beam, the pipe needs to be lowered slightly and then raised again to its original height – two 87° elbows combined with a short extension between them serve exactly this purpose. Since a separate inspection point already exists closer to the boilers in this section of the route, there is no need to use the more expensive inspection variant of the elbow here.

Comparison with other diameters of the Vaillant flue duct range

Like other parts of the Ø 160 mm range, this elbow also belongs to the highest diameter category of Vaillant flue gas exhaust systems, intended for cascades of high-output boilers – unlike the concentric systems 60/100 mm and 80/125 mm (for individual standard boilers), this is a separated system used exclusively for joining several boilers into a single collective pipe. When selecting the correct elbow, it is therefore always necessary to first know the diameter of the existing (or planned) cascade assembly – elbows with the same 87° angle but a different diameter (110, 130 or 200 mm) have different order numbers and are not interchangeable.

Ordering: When adding to or replacing a damaged part in an existing assembly, we recommend always verifying the original manufacturer's order number directly on the part or in the boiler room's project documentation, to avoid ordering an incompatible diameter.

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 standard STN EN 1443 (Chimneys), STN 73 4201 (Chimneys and flue ducts) and related technical gas industry rules (TPP), and must be carried out by an authorized and professionally qualified person – an authorized service technician or installation company with the relevant authorization for the installation of gas appliances and their exhaust systems. Commissioning the boiler room also includes an inspection of the chimney/flue duct carried out by a chimney sweep company and the issuing of the relevant inspection report.

When designing the cascade flue duct route, it is necessary to take into account in particular: the total rated heat output of all boilers in the cascade (on which the required diameter of the collective pipe depends – 160 mm or 200 mm), the maximum permissible route length and number of elbows (the manufacturer states equivalent lengths for individual fittings), the slope of horizontal sections back towards the boiler or condensate separator (usually a minimum of 3° so that the condensate can drain by gravity and does not remain standing in the pipe), sufficient securing of the pipe with spacer holders at regular intervals (typically every 1–1.5 m) so that no sagging or excessive stress on the socket joints occurs, and maintaining access to inspection openings and inspection elbows for regular cleaning and checking of patency.

When cascading several boilers into a single collective pipe, it is also necessary to respect the order and direction of feeding of individual branches according to the manufacturer's installation instructions (including the recommended use of non-return flaps for cascades of three or more boilers, so that when one boiler is shut down, flue gases from running boilers do not flow back into the shut-down unit), and to maintain the prescribed minimum elevation and direction towards the common chimney or facade/roof outlet.

Elbow care in operation

Since this elbow does not have its own inspection opening, its internal condition is checked indirectly – via the nearest inspection point on the route (inspection elbow or straight piece with an inspection opening). During a regular service inspection of the boiler room, the technician checks the patency of the entire route including this elbow and, if a problem is found (e.g. increased flow resistance), considers its temporary disassembly for cleaning, since the socket joint with a sealing ring allows this without damage.

Service, cleaning and service life

Regular inspection and cleaning of the 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 pipe sections can be checked and, if necessary, cleaned (e.g. of any deposits) without the need for complete disassembly of the entire route. The condensate separator, if part of the assembly, needs to be regularly checked 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 a manufacturer directly compatible with the given boiler range is, with correct installation and regular servicing, comparable to the service life of the boiler itself – 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 of the same manufacturer and diameter to maintain full compatibility of the joints and the validity of the warranty for the entire exhaust system.

Frequently Asked Questions

Why buy this Vaillant accessory at ATRIA.SK

The 87° Ø 160 mm elbow is the basic, most affordable solution for changing route direction where you do not need inspection access directly at the given point – at atria.sk you will find it as a separate part for supplementing or repairing an existing cascade assembly.

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