Vaillant Extension Kit for 1 Boiler in a Row, Ø 200 mm

Product detailed description

Extension kit for 1 boiler in a row, Ø 200 mm – flexible boiler room output expansion

One of the main advantages of a cascade solution over a single large boiler is the ease of future boiler room expansion – if it turns out over time that the current cascade output is no longer sufficient (for example due to a building extension, a change in its use, or increased hot water demand), it is enough to add another boiler together with this extension kit to the existing assembly, without having to replace the existing base kit or interfere with the connection of the original boilers.

The extension kit contains the necessary connecting parts to connect the new boiler's spigot to the existing collector piece of the assembly (originally established by the base kit for 2 boilers, order no. 0020106428), in an "in-a-row" configuration – i.e. for a boiler placed next to the already existing units on the same wall.

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, operating 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 (the failure of one boiler does not mean a heating outage for the entire building), better output regulation according to current needs (both the number of running boilers and the output of each of them are modulated), and easier future expansion of the boiler room with another boiler when heat demand increases.

Each boiler in the cascade has its own spigot for flue gas discharge and combustion air intake, but for practical, economic and structural reasons, the flue gases of all boilers are usually led out through one common flue collector (manifold) into 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 (not concentric) flue gas discharge system with a diameter of 160 mm or 200 mm, which is connected to the spigots of individual boilers and joins them into one common pipe.

The system is modular – it consists of base connection kits (for the first two boilers of the cascade, including the fitting required for condensate drainage), extension kits (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 kit for connecting the whole assembly to a masonry chimney shaft.

How the kit is incorporated into an existing cascade

The extension kit is always connected to the collector piece created by the previous base or extension kit in sequence – i.e. the third boiler in the cascade is connected by this kit to the collector piece of the base kit (first two boilers), the fourth boiler by another extension kit to the collector piece created by the third kit, and so on. For cascades with three or more boilers, the manufacturer recommends also adding backflow flaps to the individual branches, so that when one of the boilers is shut down, there is no backflow of flue gases from the running units into the shut-down boiler.

Unlike the base kit, this extension kit does not contain its own condensate separator – that is included only in the base kit, since it handles condensate drainage from the common collector pipe as a whole, not from the individually added branches.

Material and construction – why polypropylene (PP)

All parts of this range are made of polypropylene (PP) – a plastic used in flue 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 vapour of the flue gases – this cools 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 fuel type and operating conditions). Metal (e.g. stainless steel) flues can also withstand this load, but plastic PP systems are easier to handle, faster to install thanks to joints with sealing rings without the need for welding or special tools, and, at a comparable quality, are usually also more cost-effective.

The operating temperature of flue gases in condensing boilers is relatively low (in the order of up to approx. 80–120 °C depending on the operating mode and boiler output) – which is exactly 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 directly for cooperation with Vaillant condensing boilers of the corresponding output range and spigot type designation.

The joints of the individual parts are designed as socket connections with a rubber sealing ring (so-called socket joint) – this design allows simple, tight and yet 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

A boiler room originally designed with two Vaillant ecoTEC plus VC 806-1206/5-5 boilers (installed using the base kit 0020106428) is expanded after several years of operation with a third boiler due to increased heat demand following an extension of part of the building. Instead of replacing the entire flue assembly, it is enough to add this extension kit, with which the new boiler is connected to the existing collector piece – the original two boilers and their connection do not need to be modified in any way.

Planning a multi-stage cascade expansion

When designing a boiler room with future expansion in mind, it is useful to anticipate in advance how many extension kits will be needed over time, and to ensure sufficient space and accessibility for connecting further boilers in a row already during the initial installation. Each extension kit follows on exactly from the collector piece created by the previous kit, so the installation sequence (from the base kit gradually through the individual extension kits) must be observed.

Ordering: When ordering this extension kit, we recommend also stating which kit (base or another extension) is already installed in the boiler room, so that we can verify full compatibility of the follow-on connection.

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 technical gas industry rules (TPP), and must be carried out by an authorized and professionally competent person – an authorized service technician or an installation company with the appropriate authorization for the installation of gas appliances and their flue systems. Commissioning the boiler room also includes an inspection of the chimney/flue carried out by a chimney sweeping company and the issuance of the relevant inspection report.

When designing the route of a cascade flue, it is particularly necessary to take into account: the total rated heat output of all boilers in the cascade (on which the required diameter of the collector pipe depends – 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 (usually at least 3° so that condensate can flow away by gravity and does not remain standing in the pipe), sufficient fastening of the pipe with spacer holders 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 inspection of patency.

When cascading several boilers into one collector 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 backflow flaps for cascades with three or more boilers, so that when one boiler is shut down there is no backflow of flue gases from running boilers 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 connection after expansion

After installing this extension kit, it is advisable to pay increased attention at the next service inspection precisely to the new joint between the added boiler and the existing collector part – to verify its tightness and correct fastening, as this is the most recently added, and therefore so far least "run-in", section of the route in the whole assembly.

Storage before installation during gradual expansion

Since this extension kit is usually ordered and installed with some time delay after the original base kit (at the moment when the cascade is actually being expanded with another boiler), we recommend checking the completeness of all parts against the delivery note upon receipt, and storing it in a dry environment until installation, protected from mechanical damage to the individual sealing rings.

Service, 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 the pipe 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 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 flue 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. 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), 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 you plan to expand an existing Vaillant cascade with another boiler in the row in the future, this extension kit is exactly the part you will need – always one piece per added boiler.

When purchasing any part of the flue system, we will be happy to help you choose 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 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.