Vaillant shaft connection Ø 80/125 mm

Product detailed description

Vaillant connection for shared flue systems Ø 80/125 mm – connecting a condensing boiler to a shared flue shaft

This connection set (code 0020232147) is used for connecting a Vaillant condensing boiler with a concentric diameter of 80/125 mm to an existing shared (common) flue system of the LAS type (from the German Luft-Abgas-System), which is typically used in apartment buildings and multi-storey buildings to simultaneously handle combustion air supply and flue gas exhaust for multiple individual residential units connected to a single vertical shaft. The set includes the components needed for a certified, airtight and mechanically solid connection of the boiler outlet to the entry point of the shared shaft, in accordance with the system certification requirements for the given type of flue system.

What is a shared flue (LAS) system and why does it require a specific connection

A shared air-flue shaft system represents a vertical route passing through multiple floors of a building, into which individual condensing boilers of separate apartments or operating units are connected on each floor. This shaft simultaneously provides combustion air supply from outside the building to each connected boiler and exhausts flue gases from each boiler out of the building, while the entire shaft construction must guarantee that flue gases from one connected source do not enter the air supply of another source, nor leak back into the individual apartments. Connecting a boiler to such a system therefore requires a precisely certified component that guarantees proper separation of air and flue gas flows and the tightness of the entire connection to the shared shaft.

Function of this connection set

This set forms a transition piece between the concentric outlet of the boiler (or the subsequent flue pipe route from the boiler, diameter 80/125 mm) and the entry opening into the shared shaft, ensuring an airtight and mechanically solid connection that meets the requirements for a certified connection to a shared flue system. Such a connection usually also includes a mechanism preventing the backflow of flue gases from the shaft into the room in the event of a boiler operation failure, which is a key safety aspect for shared flue systems in multi-apartment buildings.

When is this connection set needed

• Apartments in buildings with a shared flue system – where the building's design assumes that individual apartment condensing boilers are connected to a shared shaft instead of separate façade or roof outlets,
• Replacing an older boiler with a new condensing one within an existing shared flue – where the new boiler with a diameter of 80/125 mm needs to be connected to the already existing shared shaft,
• New apartment buildings with a designed shared flue system – where connections for all planned apartment units are installed during construction together with the shared shaft,
• Renovations involving a switch to condensing technology – when modernising an older apartment building, where original atmospheric boilers are replaced with condensing units with forced flue gas exhaust connected to a modified or new shared shaft.

Set contents and technical design

The connection set includes the components needed to create a certified connection between the boiler and the entry to the shared shaft at a diameter of 80/125 mm – a transition piece adapted to the geometry of the entry opening of the specific shaft type, sealing elements ensuring airtightness of the joint, and fastening elements for mechanically securing the connection. The exact design of the transition piece is adapted to the certification of the given shared shaft system, so it is essential to verify the type and manufacturer of the existing shaft in the specific building before ordering.

Installation and safety requirements

Connecting a boiler to a shared shaft is subject to strict requirements arising from the certification of the entire system as a functional unit – components from different manufacturers or systems cannot be arbitrarily combined without violating the certification, and therefore without losing the warranty and creating potential safety uncertainty. Installation must be carried out by a professionally qualified person with the appropriate authorisation, who also ensures that the connection corresponds to the project documentation of the specific building and the certification of the given shaft type.

For multi-apartment buildings, it is also important to consider that the output and type of the newly connected boiler must correspond to the parameters for which the shared shaft is designed – uncoordinated boiler replacement by individual apartment owners without cooperation with the building administrator or the original shaft design can lead to overloading or malfunction of the entire shared system.

Compatibility

This connection set is intended for connecting Vaillant condensing gas boilers with a concentric connection of 80/125 mm to certified shared air-flue shaft systems (LAS). Before ordering, it is essential to verify with the building administrator or in the original project documentation the exact type and certification of the existing shaft system, since different shared flue systems may require different certified connection components.

Safety significance of a correct connection

An incorrect or uncertified connection of a boiler to a shared shaft represents a serious safety risk not only for the given apartment but potentially for the entire building, since a fault in the tightness or functionality of the connection can cause flue gases to leak between individual apartment units or into the common areas of the building. This is precisely why it is extremely important to use only certified, system-approved components in these systems and to entrust the installation to a professionally qualified person with proven experience with the given type of system.

Maintenance and inspection

Like the entire flue gas path, the connection to the shared shaft is subject to regular mandatory inspection by a chimney sweep, and for shared systems this inspection is even more important, since a possible fault can affect multiple apartment units at once. It is therefore recommended to strictly adhere to the prescribed inspection intervals and promptly address any deficiencies found, since delaying repairs in a shared system carries increased risk compared to a normal separate flue gas path of a single-family house.

Frequently Asked Questions (FAQ)

Can I install this connection myself without coordinating with the building administrator?
No, connecting to a shared shaft always requires coordination with the building administrator or the homeowners' association, since it involves an intervention into shared technical infrastructure affecting multiple apartment units.

Can any condensing boiler with a diameter of 80/125 mm be connected to an existing shared shaft?
No, the output and type of the boiler must correspond to the parameters for which the specific shaft is certified and designed – this needs to be verified in advance with the building's project documentation or with an expert.

What happens if a neighbouring apartment on the same system replaces its boiler with an incompatible type?
An incorrect or uncoordinated boiler replacement in one apartment can theoretically affect the operation of the entire shared system, so it is important that any changes to boilers connected to a shared shaft are coordinated with the building administrator.

Does this connection require more frequent inspection than a separate flue gas path?
The inspection interval is governed by the same legislation as for other flue gas paths, but given the shared nature of the system, it is recommended to strictly follow the prescribed intervals and promptly address any deficiencies found.

Who is responsible for maintaining the shared part of the shaft outside my apartment?
The shared parts of the shaft are usually the responsibility of the building administrator or homeowners' association, while the boiler connection within the apartment itself is the responsibility of the owner of that apartment unit.

Can this set also be used outside apartment buildings, for example in a single-family house?
This particular connection set is intended primarily for connecting to shared shafts of the LAS type, which mainly occur in multi-storey apartment buildings – for single-family houses with a separate flue gas path, other, simpler solutions are usually used, without the need for a certified shared system.

Summary

The Vaillant connection for shared flue systems Ø 80/125 mm is a certified connection set enabling the safe and reliable connection of a condensing boiler to a shared air-flue LAS system, commonly used in apartment buildings. Given the shared nature of this system, it is essential to comply with certification, coordinate with the building administrator, and ensure professional installation to guarantee the safety not only of the given apartment but of the entire building.

Recommendations for apartment owners planning a boiler replacement

Apartment owners planning to replace a condensing boiler connected to a shared shaft are advised to first contact the building administrator or homeowners' association to verify the technical parameters of the existing shaft and any restrictions regarding the output or type of the new boiler. This consultation should precede the selection and ordering of the new boiler itself, in order to avoid a situation where the purchased boiler would not be compatible with the existing shared flue exhaust system, or where the connection set would not match the diameter of the entry opening of the specific shaft.

Historical context of shared flue systems in Slovakia

Shared air-flue shaft systems began to be more widely adopted in Slovakia with the emergence of gas boilers with forced flue gas exhaust (turbo boilers) in apartment buildings, where previously common atmospheric boilers with natural flue gas exhaust into separate masonry chimneys gradually lost popularity due to lower efficiency and stricter safety requirements. The transition to central shaft solutions allowed multiple apartments in one riser to share a single technical route instead of building a separate chimney for each apartment, which was a more advantageous solution in terms of construction costs and space requirements when building larger apartment complexes.

Difference between a shared flue system and an individual connection

Unlike an individual boiler connection directly through the façade or roof of an apartment building, where each apartment has its own independent flue gas path, a shared flue system shares a common vertical route between multiple apartments. This sharing brings savings in construction costs and a uniform aesthetic appearance of the façade without numerous individual outlets, but it also brings higher requirements for certification, maintenance coordination, and responsibility for the correct functioning of the system as a whole, since a fault at the level of one connection can theoretically affect neighbouring apartments sharing the same shaft.

Procedure in the event of a fault or suspected leak in the connection

If an apartment owner notices any signs of a possible fault in the connection to the shared shaft – for example, an unusual smell of flue gases in the apartment, a boiler error message related to the flue gas path, or visible damage to the connection set – they should immediately contact an authorised Vaillant service and simultaneously inform the building administrator, since the fault may be related not only to their own connection but potentially also to the condition of the entire shared shaft. Under no circumstances should they attempt to repair or modify the connection themselves without professional assistance.

Relationship to the building's inspection documentation

For apartment buildings with a shared flue system, it is advisable for the building administrator to maintain a central register of all apartment connections to the shared shaft, including the type and output of the connected boilers, the diameter of the connection set used, the dates of the last replacement, and the results of regular inspections. This central register facilitates the planning of maintenance for the entire system and the quick identification of any discrepancies, for example if an apartment owner were to replace a boiler with a type not corresponding to the original shaft certification without informing the administrator.

Recommendations for new buildings with a planned shared flue system

When designing a new apartment building with a shared flue system, we recommend that the investor and designer consider an adequate reserve in the shaft dimensioning with regard to possible future development of the output requirements of individual apartment boilers, since boiler replacement over the lifetime of the building is a common occurrence, and the shaft should be able to accommodate slightly different but still compatible future models (with the same connection diameter of 80/125 mm) without the need for costly reconstruction of the entire shared system.

Relationship to the overall ventilation concept of the apartment building

The shared flue system is part of a broader concept of ventilation and flue gas exhaust of the apartment building, which should be comprehensively addressed already at the design stage of a new building, or thoroughly documented in older buildings where this system was installed in the past. Quality and up-to-date project documentation facilitates not only regular maintenance and inspections but also any future changes or replacements of individual boilers connected to the shared system.

Why entrust the selection of this connection set to an expert

Given the certification and safety aspects associated with connecting to a shared shaft, we strongly recommend that the final selection of the exact type and variant of this set always be confirmed by an authorised Vaillant service technician or a designer experienced with shared flue systems, based on the specific project documentation of the given building. An incorrect choice, even of a component that appears similar in size at first glance, can have more serious consequences in shared systems than in the separate flue gas path of a single-family house.

Replacement costs in the context of an overall boiler room renovation

The cost of this particular connection set forms only a small part of the total cost associated with replacing a boiler in an apartment connected to a shared flue system – the majority of the budget usually consists of the boiler itself, its installation, any necessary modifications to the heating system, and fees for coordination with the building administrator. Despite the relatively low price, however, the correct selection and certification of this connection set is crucial for the safe and trouble-free operation of the entire installation.

Impact of the number of connected apartments on shaft dimensioning

The capacity of the shared shaft is designed for a specific number of connected apartment units and their expected combined heat output. With any change to this number (for example, dividing a larger apartment into two smaller ones with two separate boilers), it is essential to reassess whether the original shaft dimensioning can handle this change without issues, which is another reason why any interventions in a shared flue system must be coordinated with an expert and the building administrator, not handled independently by individual apartment owners without a central overview of the state of the entire system.

Future availability of replacement parts

When ordering this connection set from a verified supplier of original Vaillant parts, such as atria.sk, the customer has the assurance of the availability of compatible replacement parts in the future as well, which is particularly important for systems with shared infrastructure – in the event of a future fault or need for replacement, it is necessary to use a precisely compatible component, not an arbitrary substitute, in order to maintain the certification of the entire system and the validity of the warranty for the entire flue gas path of the apartment building.

Summary of technical recommendations

For any intervention related to connecting a boiler to a shared shaft, we recommend proceeding in the following order: verifying the certification and technical parameters of the existing shaft, consulting with the building administrator, selecting a boiler with the appropriate parameters and a connection diameter of 80/125 mm, installing the certified connection set by a professionally qualified person, and finally recording the change made in the building administrator's central register for the purposes of future inspections and any further system modifications. Strictly following this procedure guarantees the safe, reliable, and long-term trouble-free operation not only of the given apartment but of the entire shared flue system of the apartment building.