Vaillant Basic Set for 2 Boilers in a Row with Condensate Trap, Ø 200 mm

Product detailed description

Basic connection set for a cascade of 2 boilers in a row, Ø 200 mm – the heart of a larger cascade boiler room

This set is the basic, starting building block when designing a cascade boiler room with a higher total output, where individual boilers (typically from the Vaillant ecoTEC plus VC 806-1206/5-5 series, i.e. boilers with an output ranging roughly from 80 to 120 kW per unit) are placed in a row – that is, side by side on one wall of the plant room. The set solves the connection of the first two boilers of the cascade into one common collecting pipe with a diameter of 200 mm, which then continues as a single flue gas outlet towards the chimney or facade/roof outlet.

An integral part of the basic set is also the condensate separator – a fitting that captures the acidic condensate formed in the common collecting pipe (not only directly in the boilers) and safely drains it away from the flue route, usually into the sewer via a neutralization box. Without this component, condensate from the common pipe could accumulate at the lowest point of the route and cause operational problems over time.

Flue gas discharge 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 larger technological boiler room – the solution is usually not one large boiler, but 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 failure of heating for the entire building), better output control according to current demand (the number of running boilers and the output of each one is modulated), and easier future expansion of the boiler room with another 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 led out through one common collecting flue (collector) into one 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 separated (not 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 pipe.

The system is modular – it consists of basic connection sets (for the first two boilers of the cascade, including the necessary condensate drainage fitting), extension sets (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 set for connecting the entire assembly to a masonry chimney shaft.

Why this set is "basic" and what exactly it contains

The designation "basic" expresses that this is the first, essential building element of every cascade with an "in a row" configuration – i.e. the set from which the connection of the first two boilers derives, and to which, in case of future expansion of the cascade with more boilers (third, fourth and further in the row), separate extension sets are connected (order no. 0020106429, each for one additional boiler). The assembly includes the necessary connecting and collecting fittings with a diameter of 200 mm, together with connections to the individual boiler outlets and the aforementioned condensate separator.

The set is designed as a closed functional unit for exactly two boilers – for a cascade with a larger number of units, it is always necessary to purchase the appropriate number of extension sets according to the total number of boilers in the given branch.

Material and construction – why polypropylene (PP)

All parts of this range are made of polypropylene (PP) – a plastic used in flue gas discharge systems of condensing boilers precisely because it perfectly resists the chemically aggressive condensate that naturally forms during the operation of condensing technology. A condensing boiler, unlike a classic (non-condensing) boiler, also uses 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) flue pipes can also withstand this load, but plastic PP systems are lighter to handle, faster to install thanks to joints with sealing rings without the need for welding or special tools, and, with comparable quality, are usually also more cost-effective.

The operating temperature of flue gases in condensing boilers is relatively low (up to approximately 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 pipe (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 outlet type designation.

The joints between individual parts are designed with a socket connection and a rubber sealing ring (so-called socket joint) – this construction allows for simple, tight, yet detachable installation without gluing or welding, which greatly simplifies any future adjustments to the route, replacement of a damaged part, or expansion of the cascade with another boiler.

Practical example

Let's imagine the boiler room of an apartment building, where, due to higher heat demand, a cascade of three Vaillant ecoTEC plus VC 806-1206/5-5 condensing boilers is designed, placed in a row on one wall of the plant room. Installation begins with exactly this basic set, which connects the first two boilers into a common collecting pipe Ø 200 mm with a condensate separator. The third boiler is then connected using a separate extension set (order no. 0020106429), which connects to the existing collecting piece of this basic set. In this way, the cascade can be gradually expanded in the future if there is a need to further increase the output of the boiler room.

Comparison with the back-to-back configuration and next steps when expanding

In addition to this set for the "in a row" connection, Vaillant also offers an analogous basic set for the "back-to-back" configuration (order no. 0020106430) – intended for boiler rooms where the boilers are not placed side by side on one wall, but on two opposite walls. The choice between the two configurations is made already at the boiler room design stage, according to the actual layout of the space, and cannot be changed later without replacing the entire basic set.

Ordering: When ordering this set, we recommend having at least a preliminary project or layout of the boiler room (number of boilers, their planned placement) available, so that we can confirm that the chosen "in a row" configuration matches your space, and also plan the required number of subsequent extension sets.

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

When designing the route of a cascade flue pipe, it is particularly necessary to take into account: 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 length of the route and the number of elbows (the manufacturer specifies 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 drain by gravity and does not remain standing in the pipe), sufficient fastening 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 inspection of patency.

When cascading several boilers into one collecting 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 check 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 incline and direction towards the common chimney or facade/roof outlet.

Care of the condensate separator in the set

The condensate separator is the part within the whole set that requires the most regular attention – during the annual (in some operations even more frequent) service inspection, its patency, possible deposits and the functionality of condensate drainage into the sewer via the neutralization box are checked. A clogged or non-functional separator can cause condensate to back up into the collecting pipe, which is why the manufacturer's installation instructions pay special attention to its inspection.

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 sections of the pipe can be inspected 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 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, 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, in order to maintain full compatibility of the joints and the validity of the warranty for 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 several high-output Vaillant boilers connected in a row, this basic set is the necessary first step of the entire assembly – do not hesitate to contact us with the parameters of your boiler room, we are happy to help you design the complete set of required parts, including extension sets.

When purchasing any part of the 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 on 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.