Vaillant Inspection Elbow 87°, Ø 160 mm

Product detailed description

Inspection Elbow 87° Ø 160 mm – why this part makes sense

The inspection elbow is one of the most important "service" parts in the entire cascade flue assembly. At first glance it is an ordinary elbow changing the direction of the pipe by nearly a right angle (exactly 87°), but it additionally has a lockable inspection (control) opening with a sealing cover built directly into the body of the elbow. Thanks to this, the pipe can be inspected at this point at any time, checked for its internal condition, possible deposits or condensate residues, and cleaned if necessary – without having to disassemble neighbouring pipe sections or dismantle the connection to the boiler itself.

Why exactly 87° and not exactly 90°? With an angle slightly smaller than a right angle, a gentler slope of the elbow's inner wall is maintained in the direction of the prescribed pipe gradient, which helps the condensate to flow away spontaneously towards the separator or drain point instead of accumulating directly in the bend – this is an important detail in condensing technology, where condensate forms continuously throughout the boiler's operation.

Flue systems for Vaillant cascade boiler rooms

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

Each boiler in the cascade has its own flue gas discharge 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 (collector) to a single chimney or through a single roof/facade penetration. This is exactly the purpose of the range of components described below – these are parts of a separate (non-concentric) flue gas discharge 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 necessary fitting for condensate discharge), extension sets (for each additional boiler added to the cascade), individual elbows of various angles for bypassing obstacles and changing the direction of the route, extensions of various lengths for bridging the distance between boilers and the riser, and finally a set for connecting the entire assembly to a brick chimney shaft.

Where this elbow is used in a cascade assembly

In practice, the inspection elbow 87° Ø 160 mm is most often installed at points where the cascade's collective pipe changes direction from a horizontal route (led, for example, under the ceiling of the boiler room from individual boilers) to a vertical riser leading to the chimney, or at a point where the layout of the boiler room requires a change of direction close to a right angle, and where the location also requires regular service access – for example, just before entering the chimney or right after the last boiler in the row.

The part is fully compatible with other components of the Ø 160 mm range (extensions, other elbows, spacer brackets, and extension/basic sets) and connects using the same socket joint with a sealing ring, so it can be added to an existing assembly at any time, or used to replace an ordinary 87° elbow where the need for inspection access has subsequently become apparent.

Material and construction – why polypropylene (PP)

All parts of this range are made of polypropylene (PP) – a plastic used in the flue gas discharge systems of condensing boilers precisely because it perfectly withstands the chemically aggressive condensate that naturally arises during the operation of condensing technology. Compared to a classic (non-condensing) boiler, a condensing boiler also utilises the latent heat contained in the water vapour of the flue gases – this cools below the dew point in the flue gas heat exchanger and condenses, and the resulting condensate is slightly acidic (pH approximately 3–5, depending on the type of fuel and operating conditions). Metal (e.g. stainless steel) flues can also withstand this load, but plastic PP systems are lighter to handle, faster to assemble 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 about 80–120 °C depending on operating mode and boiler output) – this is precisely why the use of plastic PP piping instead of a classic metal flue (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 specifically for use with Vaillant condensing boilers of the corresponding output range and port designation.

The joints between individual parts are made using a socket connection with a rubber sealing ring (the so-called socket joint) – this design allows simple, tight, yet demountable assembly without gluing or welding, which significantly simplifies any future route modifications, replacement of a damaged part, or expansion of the cascade with an additional boiler.

Practical example

Let us imagine a boiler room with two Vaillant condensing boilers connected in a row, whose flue gases are led by a common Ø 160 mm collective pipe to a vertical riser and from there to the chimney. Just before entering the riser is a logical place to install the 87° inspection elbow – a chimney sweep or service technician can thus easily open the inspection cover during the annual chimney inspection, check the condition of the inside of the pipe, and remove any deposits, without having to disconnect the boilers or dismantle longer sections of the route. In assemblies where an additional boiler is later added to the cascade (for example, an extension set for 1 boiler in the row), the inspection elbow is usually moved closer to the new, currently last connection point before the common riser.

Comparison with other diameters in the Vaillant flue range

Vaillant offers flue gas discharge systems gradually in diameters of 60/100 mm and 80/125 mm (concentric, for individual standard wall-hung boilers), 110 mm and 130 mm (separate, for higher-output units and smaller S1/S2/S3-type cascades), and finally 160 mm and 200 mm (separate, for large cascades of high-output boilers). The 87° inspection elbow with a diameter of 160 mm belongs to this highest category – its use makes sense only in assemblies where the cascade's collective pipe already exceeds the diameter typical for one or two smaller boilers. When designing a new boiler room, it is therefore important to first determine the total output and number of boilers in the cascade, and only then choose the correct diameter and, with it, the correct order number of this inspection elbow (Ø 160 mm, not Ø 110 mm or Ø 130 mm, which have different order numbers and dimensions).

Ordering: When ordering, we always recommend stating the exact manufacturer's order number (0020095554), since visually similar parts with a different diameter (110, 130 or 200 mm) have different socket dimensions and are not interchangeable with the Ø 160 mm assembly.

Assembly and installation

The installation of a flue gas discharge 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 flues) and related gas technical rules (TPP), and must be carried out by an authorised and professionally competent person – an authorised service technician or an installation company with the appropriate authorisation for the installation of gas appliances and their flue gas discharge systems. Commissioning of the boiler room also includes an inspection of the chimney/flue carried out by a chimney sweep company and the issuing of the relevant inspection report.

When designing the route of a cascade flue, 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 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 at least 3° so that condensate can flow away by gravity and does not remain standing in the pipe), sufficient securing of the pipe with spacer brackets at regular intervals (typically every 1–1.5 m) so that there is no sagging or excessive stress on the socket joints, and maintaining access to inspection openings and inspection elbows for regular cleaning and checking of patency.

When cascading several boilers into one collective pipe, it is also essential to respect the order and direction of connection of individual branches according to the manufacturer's installation instructions (including the recommended use of non-return flaps in cascades with 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 observe the prescribed minimum elevation and direction towards the common chimney or facade/roof outlet.

Care of the inspection opening

The lockable inspection opening cover is fitted with a sealing ring, which must be checked each time it is opened and closed – a damaged or hardened seal must be replaced in time, otherwise there is a risk of flue gas leakage or, conversely, unwanted air intake into the pipe at that point. During a routine annual service inspection, it is recommended to open the cover, visually check the inside of the pipe around the bend (where any deposits accumulate most often), and clean it if necessary with a dry or slightly damp cloth.

Service, cleaning and service life

Regular inspection and cleaning of the flue gas discharge 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 cleaned if necessary (e.g. of any deposits) without having to completely dismantle the entire route. The condensate separator, if included in the assembly, must be regularly checked and emptied/flushed if necessary to prevent it from clogging and condensate backing up into the pipe.

The service life of a quality PP flue gas discharge 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 – that is, roughly 15 or more years of operation. When replacing or adding individual parts in the future (for example, when expanding the cascade with an additional boiler), it is advisable to use original components of the same manufacturer and diameter, in order to maintain full compatibility of the joints and the validity of the warranty on the entire flue gas discharge system.

Frequently Asked Questions

Why buy this Vaillant accessory at ATRIA.SK

If you are planning a cascade boiler room with at least one point in the route where regular service access will be needed (typically just before entering the riser or chimney), the 87° Ø 160 mm inspection elbow is the right choice instead of an ordinary elbow – the difference in price compared to the benefit of easier future maintenance is negligible.

When purchasing any part of the flue gas discharge system, we will be 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 the design 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.