Vaillant Shaft Connection Set, Ø 200 mm

Product detailed description

Shaft Connection Kit Ø 200 mm – connecting a cascade to an existing chimney

Many boiler rooms, especially during renovations of older buildings or in larger facilities with an existing masonry chimney, solve flue gas discharge from a cascade of condensing boilers by running plastic PP piping inside the original chimney shaft instead of building a completely new, separate riser routed through the facade or roof. This kit solves exactly this transition – connecting the vertical riser of the cascade's collector flue duct (200 mm diameter) to the entry point of an existing masonry shaft, including the necessary fixing and sealing at the entry point.

Using an existing chimney shaft as a supporting structure for new plastic piping is, in boiler room renovations, often a more advantageous and structurally simpler solution than building a new separate flue, since the shaft already provides a ready-made, structurally verified route above the roof of the building.

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, 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 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 outlet and combustion air intake port, but for practical, economic and structural reasons, the flue gases of all boilers are usually discharged through one common collector flue duct (manifold) into a single chimney or through a single roof/facade penetration. This is exactly the purpose of the range of components described below – parts of a separate (non-concentric) flue gas discharge system with a diameter of 160 mm or 200 mm, which connects to the outlets of individual boilers and joins them into one common duct.

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

What the kit solves and what it is combined with

The kit provides the mechanical fixing and airtight sealing of the point where the new PP piping of the cascade enters the space of an existing masonry shaft, and connects to the rest of the collector route made up of other components in the Ø 200 mm range (elbows, extensions, basic and expansion cascade kits). Inside the shaft itself, the piping then continues above roof level, where the appropriate chimney termination/cap must also be addressed according to the specific type of shaft and the requirements of the chimney sweep inspector.

Since this involves an intervention in an existing building structure of the chimney, the installation is always preceded (and followed) by an assessment of the shaft's condition and its suitability for inserting plastic piping, carried out by a chimney sweep company, which also issues an inspection report after installation is completed.

Material and construction – why polypropylene (PP)

All parts in this range are made of polypropylene (PP) – a plastic used in the flue systems of condensing boilers precisely because it perfectly withstands the chemically aggressive condensate that naturally forms during the operation of condensing technology. A condensing boiler, unlike a conventional (non-condensing) boiler, also makes use of the latent heat contained in the water vapor of the flue gases – this vapor is cooled 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 fuel type and operating conditions). Metal (e.g. stainless steel) flue ducts can also withstand this load, but plastic PP systems are easier to handle, quicker 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 about 80–120 °C depending on the operating mode and boiler output) – which is exactly why using plastic PP piping 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 specifically for use with Vaillant condensing boilers of the corresponding output range and outlet type designation.

The joints between individual parts are made using socket connections with a rubber sealing ring – this design allows simple, tight, 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 an additional boiler.

Practical example

During the renovation of the boiler room of an older apartment building, where the original single large boiler is replaced by a cascade of two to three smaller Vaillant condensing boilers, the existing masonry chimney that originally served the original boiler is used for flue gas discharge. New PP piping with a diameter of 200 mm is introduced into its shaft using this kit, connecting to the rest of the collector route from the boiler cascade – this solves flue gas discharge without the need to build a completely new chimney or route piping through the building's facade.

Alternative to this kit – routing via a new separate riser

Where an existing masonry chimney is not suitable for inserting plastic piping (for example due to unsuitable shaft dimensions, poor technical condition, or inaccessibility), an alternative is to build a completely new separate riser routed through the building's facade or directly through the roof, made up of standard components from the Ø 200 mm range (extensions, elbows) up to a suitable roof or facade termination. This shaft connection kit is therefore suitable precisely when the existing chimney is suitable in terms of condition and dimensions, and its use is structurally and economically more advantageous than building a new route.

Ordering: Before ordering this kit, we recommend having the existing chimney assessed by a chimney sweep company – the result of this assessment (suitable/unsuitable for inserting piping) is decisive for choosing between this kit and the alternative solution of a new riser.

Installation and mounting

The installation of flue gas discharge systems 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 regulations (TPP), and must be carried out by an authorized and professionally qualified person – an authorized service technician or an installation company with the relevant authorization for installing gas appliances and their flue systems. Commissioning the boiler room also includes an inspection of the chimney/flue duct carried out by a chimney sweep company and the issuance of the relevant inspection report.

When designing the route of a cascade flue duct, it is particularly important to consider: the total nominal heat output of all boilers in the cascade (which determines the required diameter of the collector piping – 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 drain by gravity and not remain standing in the piping), sufficient fixing of the piping with spacer brackets at regular intervals (typically every 1–1.5 m) so that no sagging or excessive stress occurs on the socket joints, and maintaining access to inspection openings and inspection elbows for regular cleaning and checking of clearance.

When cascading multiple boilers into one collector duct, 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 check 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 maintain the prescribed minimum rise and direction towards the common chimney or facade/roof outlet.

Caring for the shaft connection

The point where the new PP piping enters the masonry shaft is, in terms of long-term tightness, one of the most important points of the whole assembly – it combines a new plastic part with an existing, older chimney building structure. During regular chimney inspections, the chimney sweep company also checks precisely this transition, including the condition of the seal and fixing, since any leaks could lead to flue gases penetrating into the building structure outside the piping itself.

Servicing, cleaning and service life

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

The service life of a quality PP flue system from the 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 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 system.

Frequently asked questions

Why buy this Vaillant accessory at ATRIA.SK

If your renovated or newly built cascade boiler room uses an existing masonry chimney, this kit is a key part for safely and tightly connecting the new PP piping of the cascade to the shaft entry point – we recommend consulting the suitability of the specific chimney with a chimney sweep company in advance.

When purchasing any part of a flue gas discharge 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; for larger assemblies, we will inform you in advance of the delivery date if necessary.