ATTACK KT extension 1 m, diameter 60/100, painted

Product detailed description

ATTACK KT extension 1 m, diameter 60/100, painted is part of the original flue gas extraction and combustion air intake system ATTACK KT / KT PLUS, designed for wall-mounted condensing gas boilers ATTACK Condensing. This component belongs to the category: extension 1000 mm, diameter 60/100 mm, material galvanized steel with painted surface finish.

Closed combustion chamber and flue extraction in ATTACK condensing boilers

ATTACK condensing gas boilers operate with a closed (turbo) combustion chamber – unlike older atmospheric boilers, they do not need air from the room in which they are installed, nor a functional masonry chimney. They draw combustion air directly from outside the building and discharge flue gases outside using forced draught provided by a fan built into the boiler. In practice, this closed circuit is solved in two ways: with coaxial (concentric) piping, where a smaller pipe for air intake runs inside a larger pipe and the annular space is used for flue gas discharge, or with a separate system using two independent pipes. The coaxial design with a diameter of 60/100 mm is the most common solution for boilers up to approx. 35 kW, as it allows both extraction and intake to be routed through a single wall or roof penetration, is quick to install, and has a discreet appearance.

Every component of the extraction assembly – elbow, extension, condensate collector, chimney terminal, and manifold – must be airtight, resistant to flue gas temperatures and to condensate, which is produced in large quantities during operation of a condensing boiler precisely because the boiler is able to utilize the latent heat of water vapor in the flue gases. It is this condensate that makes it unsafe to replace the ATTACK KT system with a common chimney component intended for atmospheric boilers – such components are not designed for permanent contact with acidic condensate nor for the correct slope needed to drain condensate back to the boiler or to the collector.

Extension – how the length of the extraction route is designed

Extensions are the basic building blocks of the entire extraction route – by combining 1 m and 0.5 m pieces, the total length of the piping from the boiler outlet to the roof or facade can be precisely adjusted to match the specific ceiling height or wall thickness of the building. For the coaxial 60/100 mm system, the manufacturer specifies the maximum permissible extraction length (the sum of all straight sections and equivalent lengths of elbows) in the operating manual for the specific boiler model – usually in the range of 10 to 15 m equivalent length for the Condensing KT/KST/KZT range, with each 90° elbow counted as approximately 1 to 1.5 m of straight pipe and a 45° elbow as approximately 0.5 m.

Exceeding the maximum length leads to increased resistance on both the flue gas and intake sides, which may be evaluated by the boiler as a draught fault and cause it to shut down via a safety cutoff. Therefore, when designing the route, the required length should always first be calculated based on the actual layout (ceiling height, wall thickness, roof overhang), and only then should the combination of extensions, elbows, and the terminal be ordered.

Component length: 1000 mm.

Example of a typical connection in a real installation:
boiler → flange → extension (added to reach the exact length) → elbow → chimney.

Step-by-step installation procedure

1. Based on the route design, calculate in advance how many 1-meter and 0.5-meter extensions you need to reach the target length.
2. Connect the components using the socket-into-socket push-fit system, ensuring correct insertion direction (according to markings).
3. For horizontal runs, check a minimum slope of 3° toward the boiler or the nearest condensate collector using a spirit level.
4. Mechanically support/secure longer horizontal sections with clamps according to the installation manual.
5. Check the tightness of all new joints before continuing with additional route components.

Material and construction

This component is made of galvanized steel with an additional painted surface finish, which increases resistance to weather influences on the exterior part of the route (for example, the chimney terminal on the roof) and also gives the component an aesthetic, uniform appearance matching the design of ATTACK Condensing boilers. The surface finish withstands normal flue gas temperatures from a condensing boiler and short-term contact with condensate, provided the correct pipe slope is maintained so that condensate does not remain standing in the component for long periods.

System classification: coaxial (concentric). Design: both vertical and horizontal.

Compatibility with ATTACK boilers

Component PR37 is designed for the connection system common to the entire range of wall-mounted condensing boilers ATTACK ACKT20, ACKT28 and ACKT48 (Condensing KT range), ATTACK KST24 (Condensing KST) and ATTACK KZT25 (Condensing KZT). Before ordering, we recommend verifying in the installation manual for the specific boiler model the exact type of connection socket and the maximum permitted length of the extraction route, as this may vary slightly depending on the boiler output (20, 28 or 48 kW for the KT range).

Installation and warnings

Extensions are joined using the socket-into-socket push-fit system; joints are sealed either with an integrated gasket or with additional silicone sealant resistant to flue gas temperatures, depending on the component type. For horizontal runs, a minimum slope of 3° (approximately 3 cm per meter of length) toward the boiler or the nearest condensate collector must be maintained so that condensate does not remain standing in the pipe.

As a general rule, horizontal extraction sections must have a slope of at least 3° toward the boiler or the nearest condensate collector so that condensate does not accumulate in the pipe. Installation should be carried out by a person qualified to install gas appliances and their extraction systems, in accordance with the installation manual for the specific boiler and with the standard EN 15287.

Standards and safety requirements

Installation of flue gas extraction for condensing boilers in Slovakia is governed primarily by the standard EN 15287 (Chimneys – Design, installation and commissioning of chimneys – Part 1: Chimneys for fan assisted appliances), which sets minimum distances of the terminal from windows, ventilation openings, neighboring properties, and ground level, as well as the minimum height of the terminal above the roof plane. The boiler itself and its extraction system must also meet the requirements of EN 483 (type C gas boilers) and be installed in accordance with applicable technical operating regulations for gas equipment.

Installation may only be carried out by a person qualified to install and service gas appliances, who must issue an inspection report or commissioning protocol upon completion. For any change to the route compared to the originally approved design (e.g. additional route extension, change in the number of elbows), it is necessary to check whether the boiler still falls within the parameters permitted by the manufacturer – otherwise there is a risk not only of boiler malfunction but also loss of warranty and, in extreme cases, a safety risk of flue gas leakage.

Maintenance and service inspection

Straight sections of pipe, if properly installed (correct slope, mechanical fastening), do not require special maintenance. During a service inspection, it is recommended to visually check whether longer horizontal sections have sagged and whether the push-fit joints remain airtight.

The recommended inspection interval for the entire extraction route is once a year, usually as part of the regular boiler service inspection carried out by an authorized service technician. On this occasion, this specific component is also checked, along with the patency of the condensate path and the overall condition of the joints along the entire route from the boiler to the outlet outside the building.

Typical usage scenarios

Scenario 1 – fine-tuning the exact route length for a low ceiling height room: the distance from the boiler to the ceiling is unusual and does not match an exact multiple of 1 m – it is therefore supplemented with a combination of 1 m and 0.5 m extensions so that the sum exactly matches the actual height.

Scenario 2 – extending the route for a thicker wall or larger roof overhang: for thicker perimeter walls or a larger roof overhang, the required number of extensions is inserted between the boiler and the terminal component so that the route reliably reaches outside the building.

Related components in the ATTACK KT range

The one-meter extension PR37 is complemented in the range by the shorter 0.5 m version PR38 – by combining both pieces, any route length can be assembled in 0.5 m increments. When ordering a larger number of meters (for example, for a longer run through an attic), it is generally more advantageous to use as many 1 m pieces as possible and fine-tune only the remainder with a 0.5 m component.

A complete overview of all components of the ATTACK KT / KT PLUS flue extraction system (elbows, extensions, chimney terminals, condensate collectors and manifolds for diameters 60/100 mm and 80 mm) can be found in the category Condensing boilers > flue extraction, flue pipes > accessories by brand > Attack on this e-shop.

Summary

ATTACK KT extension 1 m, diameter 60/100, painted (code PR37) is a component of the type extension 1000 mm with a diameter of 60/100 mm made of galvanized steel with a painted surface finish, belonging to the coaxial (concentric) system. Recommended installation orientation: both vertical and horizontal. The component is designed for boilers ATTACK ACKT20, ACKT28 and ACKT48 (Condensing KT range), ATTACK KST24 (Condensing KST) and ATTACK KZT25 (Condensing KZT) and is part of the wider range of ATTACK KT extraction components available on this e-shop, allowing a complete flue extraction route to be assembled precisely according to the layout of a specific installation.

Frequently asked questions

Is it better to buy longer 1 m extensions, or combine them with 0.5 m pieces?
It depends on the exact length that needs to be reached. By combining 1 m (PR37) and 0.5 m (PR38) pieces, practically any length can be assembled in 0.5 m steps without the need to cut the pipe, which is simpler and preserves the tightness of the original push-fit joints.

Can the PR37 extension be cut to a custom length if I need a non-standard size?
The manufacturer's recommended procedure is to combine whole 1 m and 0.5 m pieces to achieve the exact length without cutting, since cutting may compromise the push-fit joint and its tightness. If cutting is truly necessary, it should be performed by an experienced installation team, taking care to preserve the sealing surface.

Do I need a functional chimney for an ATTACK condensing boiler?
No. ATTACK Condensing KT, KST, and KZT condensing boilers have a closed combustion chamber with forced draught – they draw combustion air from outside and discharge flue gases through their own extraction system (coaxial 60/100 mm or separate Ø80/Ø80). A masonry chimney is therefore not needed; a wall or roof penetration for the plastic-aluminum piping is sufficient.

What is the maximum flue extraction length for coaxial 60/100 mm piping?
The exact value depends on the specific boiler model (ACKT20, ACKT28, ACKT48, KST24 or KZT25) and is stated in the installation manual – it is usually an equivalent length of 10–15 m, with a 90° elbow counted as approx. 1–1.5 m and a 45° elbow as approx. 0.5 m of straight pipe. Exceeding the limit increases resistance and may cause a boiler fault message.

Why does water actually drip from the flue extraction?
A condensing boiler cools the flue gases to such an extent that the water vapor contained in them condenses – it is precisely from this additional heat that the boiler achieves its high efficiency. The resulting condensate is slightly acidic and must be drained via the condensate collector into the boiler's siphon; that is why all horizontal pipe sections have a prescribed slope toward the boiler or collector.

Can the coaxial 60/100 mm pipe be combined with the separate Ø80/Ø80 system?
Yes, this is exactly the purpose of the manifold (e.g. PR51, PR51A or PR51B), which splits a single coaxial pipe from the boiler into two separate Ø80 mm pipes. It is used for longer routes or when the intake and exhaust need to be routed in different directions.

Can I combine components of different diameters or from another manufacturer with the ATTACK extraction system?
It is recommended to use a certified system from the same manufacturer, as specified in the manual for the specific boiler (for ATTACK Condensing boilers, this is the ATTACK KT/KT PLUS system). Combining components of different diameters, materials, or from other manufacturers may result in leaks, incorrect condensate drainage, and loss of the boiler warranty.

How often should the extraction pipe and condensate collector be checked?
A visual check of joint tightness and condensate collector patency is recommended at least once a year, ideally during the regular boiler service inspection. For facade or roof terminals, it is also necessary to check that the terminal grille is not blocked by leaves, insects, or snow.

Does the flue extraction need to be insulated?
When routed through heated space, insulation is usually not necessary, since the surface temperature of the coaxial pipe is low. For longer sections routed through unheated space (attic, facade) or where there is a risk of moisture condensation on the pipe surface, additional insulation is recommended, especially at the condensate collector, to prevent freezing.

What happens if the flue extraction is undersized or too long?
If the maximum equivalent extraction length is exceeded or there are leaks, the boiler will usually report a fault related to flue gas/air flow (fan fault, pressure switch fault, or flue path fault) and shut down for safety reasons. The solution is to recalculate the route according to the manual and make adjustments if necessary (shorter route, fewer elbows, or switching to a separate Ø80/Ø80 system).

Can this component be used in a cascade connection of multiple boilers?
For cascades with multiple boilers, a separate Ø80/Ø80 system with a common collecting flue is usually used, or separate terminals for each boiler according to the cascade's project documentation. The specific components (extensions, elbows, manifolds) are also compatible in this configuration, but minimum terminal distances according to EN 15287 must be maintained.

How do I find out exactly which components I need for my installation?
The most reliable approach is to base your decision on the installation manual for the specific boiler model (ACKT20/28/48, KST24, KZT25), which contains diagrams of typical connections and the maximum permitted lengths. For a more complex or non-standard layout (long route, penetration through multiple floors, cascade), we recommend consulting an installation company or the seller directly before ordering the exact number of pieces.

Does condensate from the flue extraction need to be neutralized before being discharged into the sewer?
For typical family homes with a small boiler output, neutralization is usually not required given the small amount of condensate and its dilution with other wastewater; however, applicable legislation and the requirements of the local sewer administrator must be followed. For larger outputs or boiler cascades, it is recommended to install a condensate neutralization device before discharge into the public sewer.

Is operation of a condensing boiler with this type of extraction louder than with a classic chimney?
Forced draught (from the boiler's fan) may be associated with a slight operating noise, which, however, is minimal when the route is properly installed and mechanically secured (without freely vibrating pipe sections) and is generally comparable to or lower than the noise of a classic atmospheric boiler with chimney extraction.

Can installation of this component be done by yourself, or is a professional required?
The mechanical connection of the components (push-fit system) itself is simple, but connecting the extraction to the condensing boiler, calculating the maximum route length, and commissioning the boiler must be carried out by a person qualified to install gas appliances – this is both a manufacturer requirement and a legal requirement for maintaining the warranty and ensuring safe operation.

Does the number and type of these components affect gas consumption or boiler efficiency?
They do not directly affect consumption, but they do so indirectly – the greater the resistance of the extraction route (many elbows, a route at the limit of the maximum length), the more energy the boiler's fan must expend to overcome this resistance, and the sooner the boiler may limit its output or report a fault. Designing the route with as few components as possible is therefore also advisable from the point of view of operating economy.

Warranty

This ATTACK extraction system component is covered by a 24-month warranty from the date of shipment from the warehouse, the same as other accessories for ATTACK condensing boilers. In the event of a warranty claim, we recommend keeping the proof of purchase and, if necessary, photo documentation of the installation method, since the functionality of extraction systems is closely linked to the correctness of installation (compliance with slope, maximum route length, and distances according to the manual).