Vaillant Flue Extension 1.0 m, Ø 160 mm

Product detailed description

Flue Extension 1.0 m Ø 160 mm – universal medium module

The one-metre-long extension is the most universal module of the three available lengths (0.5 m, 1.0 m, 2.0 m) – it covers common distances between collecting pieces and elbows in an average-sized boiler room, and in practice it is usually the module used in the largest quantity in a single assembly. It is used both for directly bridging the distance between two fittings and in combination with a shorter (0.5 m) or longer (2.0 m) module to achieve the exact total length of the designed route.

Like the other lengths, this module is connected via a socket joint with a sealing ring, allowing fast installation without gluing or welding and easy future disassembly during servicing or route modification.

Flue exhaust 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, office 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 (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 is modulated), and easier future expansion of the boiler room with another boiler if heat consumption increases.

Each boiler in the cascade has its own flue gas exhaust and combustion air intake connection, but for practical, economic and structural reasons, the flue gases of all boilers are usually led out via one common collecting flue (collector) into a single chimney or through a single roof/facade passage. This is exactly the purpose of the range of components described below – these are parts of a separate (non-concentric) flue exhaust system with a diameter of 160 mm or 200 mm, which connects to the individual boiler outlets and combines 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 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 whole assembly to a masonry chimney shaft.

Use in the assembly

The 1.0 m extension is most commonly installed on the main straight sections of the route between the boiler and the first elbow, between two elbows when bypassing an obstacle over a longer distance, or as part of a vertical riser towards the chimney, where the height of one floor needs to be bridged in sections.

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

Material and construction – why polypropylene (PP)

All parts of this range are made of polypropylene (PP) – a plastic used in condensing boiler flue exhaust systems precisely because it perfectly withstands the chemically aggressive condensate that naturally forms during the operation of condensing technology. A condensing boiler, unlike a classic (non-condensing) boiler, also utilises the latent heat contained in the water vapour of the flue gases – this is cooled below the dew point in the flue gas heat exchanger and condenses, and the resulting condensate is mildly 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 install thanks to sealing-ring joints without the need for welding or special tools, and, for comparable quality, are usually also more cost-effective.

The operating temperature of flue gases in condensing boilers is relatively low (typically up to approx. 80–120 °C depending on the operating mode and output of the boiler) – 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 condensate resistance. The system is certified and dimensioned by the manufacturer specifically for use with Vaillant condensing boilers of the corresponding output range and connection type.

The joints between individual parts are made using a socket connection with a rubber sealing ring (a so-called socket joint) – this design allows for simple, tight, and yet demountable 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

When routing a vertical riser of a cascade flue through a technical shaft with a floor height of approximately 3 metres, the route can be assembled, for example, from three one-metre extensions supplemented by a shorter 0.5-metre piece for exact adjustment to the inspection point or connection to the roof passage – the one-metre module here forms the basic "building block" unit of the entire riser length.

Comparison of available Ø 160 mm extension lengths

The one-metre-long extension is the middle choice of the three available lengths (0.5 m, 1.0 m, 2.0 m) and is used most frequently in practice precisely because it covers common distances between fittings well in an average-sized boiler room. When calculating the material for the entire route, this module is usually used as the basic unit, supplemented as needed with a shorter (0.5 m) or longer (2.0 m) piece for precise adjustment to the designed length.

Ordering: When ordering material for a larger assembly, we recommend counting on this module as the basic length unit and purchasing shorter/longer variants only for the final adjustment of the remaining 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 flues) and related technical gas industry rules (TPP), and must be carried out by an authorised and professionally qualified person – an authorised service technician or an installation company holding the relevant authorisation to install gas appliances and their exhaust systems. Commissioning of the boiler room also includes an inspection of the chimney/flue carried out by a chimney sweep company and the issuance of the relevant inspection report.

When designing the route of a cascade flue, it is necessary to consider in particular: the total rated heat output of all boilers in the cascade (this determines the required diameter of the collecting pipe – 160 mm or 200 mm), the maximum permissible route length and the number of elbows (the manufacturer states equivalent lengths for individual fittings), the slope of horizontal sections back towards the boiler or the condensate separator (generally at least 3° so that condensate can flow away by gravity and does not remain standing in the pipe), sufficient support 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 collecting pipe, it is also essential to respect the order and direction of feeding the individual branches according to the manufacturer's installation manual (including the recommended use of non-return flaps for 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 rise and direction towards the common chimney or facade/roof outlet.

Care of the extension during operation

For the one-metre-long extension, the annual inspection primarily checks the condition and spacing of the spacer brackets (the recommended fastening spacing is generally 1–1.5 m), the maintenance of the prescribed slope towards the condensate separator, and the tightness of both socket joints at the ends of the section. When properly fastened, this part does not require any special maintenance beyond routine visual inspection.

Storage and handling before installation

The one-metre-long pipe section requires somewhat more space during transport and storage than the shorter 0.5-metre variant, but it is still an easily manageable part. We recommend storing it lying flat on a level surface (not hanging by one end) to prevent permanent deformation of the pipe's straight shape before it is installed in the route, and protecting the sealing rings at both ends from contamination or mechanical damage until installation.

When ordering several pieces at once (for example, when assembling a longer route from several one-metre extensions), we recommend ordering all parts from a single delivery to ensure the same production batch of material and thus a consistent surface appearance of the individual sections in cases where the pipe remains visible after installation (for example, in a technical room with an exposed installation).

Service, cleaning and service life

Regular inspection and cleaning of the flue 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 to completely dismantle the entire route. The condensate separator, if part of the assembly, must be regularly checked and, if necessary, emptied/flushed to prevent it from clogging and causing condensate to back 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 – that is, in the order of 15 or more years of operation. When replacing or adding individual parts in the future (for example, when expanding the cascade with another boiler), original components of the same manufacturer and diameter should be used 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 Flue Extension 1.0 m Ø 160 mm is the most universal building module of the entire assembly – we recommend it as the basic unit when calculating the material needed for any cascade flue route.

When purchasing any part of the flue exhaust system, we are happy to help you choose the right combination of components for your specific boiler room – just contact us with details on the type and number of boilers, or with 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.