ATTACK ATC vertical flange for boiler, diameter 60/100, AL

Product detailed description

ATTACK ATC vertical flange for boiler connection, diameter 60/100, AL is part of the original flue gas discharge and combustion air intake system ATTACK KT / KT PLUS, designed for wall-mounted condensing gas boilers ATTACK Condensing. This component belongs to the category: connecting flange for boiler (vertical), diameter 60/100 mm, material aluminium (AL).

Sealed combustion chamber and flue gas discharge in ATTACK condensing boilers

ATTACK condensing gas boilers operate with a sealed (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 outward also by forced draught, provided by a fan built into the boiler. In practice, this sealed 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 serves 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 discharge and intake to be routed through a single opening in the wall or roof, is quick to install, and is aesthetically unobtrusive.

Every element of the discharge assembly – elbow, extension, condensate trap, chimney terminal and splitter – 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 utilise the latent heat of water vapour in the flue gases. This condensate is precisely the reason why the ATTACK KT system cannot be safely replaced with a standard chimney component intended for atmospheric boilers – such components are not designed for permanent contact with acidic condensate nor for the correct slope that drains condensate back into the boiler or into the trap.

Connecting flange – interface between the boiler and the discharge system

The ATC flange is the first component installed directly onto the boiler outlet, and forms the interface between the boiler neck and the rest of the discharge system. Its purpose is to ensure a perfectly airtight and mechanically strong joint that withstands thermal stress and slight vibrations during operation of the boiler's fan, while also allowing easy removal during servicing (cleaning of the flue gas path, tightness check) without having to dismantle the entire discharge route.

The vertical version of the flange is used for boilers with an upward-facing outlet (the most common arrangement for wall-mounted condensing boilers ATTACK Condensing KT, KST and KZT), from which the pipe continues vertically upward to the chimney terminal, or turns shortly after the flange via an elbow into a horizontal direction toward the façade.

Example of a typical setup in a real installation:
ATC flange (on the boiler neck) → 0.5 m extension → 90° elbow → horizontal terminal pipe (façade).

Step-by-step installation procedure

1. Check the diameter and type of the connecting neck on the boiler according to the manual for the specific model.
2. Fit the seal supplied with the flange and slide/screw the flange onto the boiler neck according to the manufacturer's instructions.
3. Tighten the screw joints evenly to avoid overloading the thin-walled material of the component.
4. Connect the next component of the route to the flange (extension, elbow or splitter) according to the planned layout.
5. Once the entire route is completed, perform a tightness check before the boiler is first put into operation.

Material and construction

The aluminium design is used for coaxial components that are in direct contact with hot flue gases and condensate. Aluminium is lightweight, does not corrode on contact with acidic condensate (unlike ordinary galvanised steel without additional treatment), and withstands temperature fluctuations well during boiler start-up and shutdown. Joints are sealed with silicone or EPDM seals resistant to the temperatures of flue gases from a condensing boiler (typically up to approx. 120 °C) as well as to moisture.

System classification: coaxial (concentric). Design: vertical.

Compatibility with ATTACK boilers

The PR35 component 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 checking the exact type of connecting neck and the maximum permitted length of the discharge route in the installation manual for the specific boiler model, as this may vary slightly depending on the boiler output (20, 28 or 48 kW for the KT range).

Installation and warnings

The flange is installed directly onto the boiler neck according to the manufacturer's manual, using the seal supplied with the component. Screw joints are tightened evenly, without overloading plastic or thin-walled aluminium parts. Once the entire route is completed, a tightness test is performed (visual inspection of joints, or a smoke test according to the service technician's instructions) before the boiler is first put into operation.

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

Standards and safety requirements

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

Installation may only be carried out by a person professionally qualified for the installation and servicing of gas appliances, who issues an inspection report or commissioning certificate upon completion. In the event of any change to the route compared to the originally approved design (e.g. additional extension of the route, 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 of loss of warranty and, in extreme cases, a safety risk of flue gas leakage.

Maintenance and service inspection

The flange does not wear out during normal operation, but during servicing (cleaning of the flue gas path of the heat exchanger) it is usually removed and reinstalled – during each such handling, the condition of the seal must be checked and replaced in case of visible wear, in order to maintain the tightness of the joint to the boiler.

The recommended inspection interval for the entire discharge route is once a year, usually as part of the regular service inspection of the boiler carried out by an authorised service technician. On this occasion, this specific component is also inspected, 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 – new boiler installation: the flange is the first component installed directly during boiler installation, before connecting any other component of the route. Without it, it is not possible to connect the discharge system to the boiler.

Scenario 2 – replacement of an old discharge system with a new one: during installation modernisation, the original flange is removed along with the old piping and replaced with a new one, to ensure a tight joint corresponding to the current boiler design.

Related components in the ATTACK KT range

The ATC flange is the entry point of the entire route, and is directly followed by extensions PR37/PR38, elbows PR40/PR41 or splitters PR51/PR51A/PR51B, if a switch to the separate Ø80/Ø80 system is made right after the boiler. Without this component (or its equivalent from another manufacturer's design), it is not possible to connect any further component of the discharge route to the boiler.

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

Summary

ATTACK ATC vertical flange for boiler connection, diameter 60/100, AL (code PR35) is a component of the type connecting flange for boiler (vertical) with a diameter of 60/100 mm made of aluminium (AL), belonging to the coaxial (concentric) system. Recommended installation orientation: vertical. 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 discharge components available on this e-shop, allowing you to assemble a complete flue gas discharge route exactly according to the layout of the specific installation.

Frequently asked questions

Can the PR35 flange also be used with the KST24 and KZT25 models, or only with the KT range?
The vertical ATC flange is designed for the connecting neck common to the entire ATTACK Condensing range (KT, KST and KZT), so it is compatible with all models ACKT20, ACKT28, ACKT48, KST24 and KZT25 – in case of doubt about a specific series design, we recommend checking the neck dimension in the boiler manual.

Can the PR35 flange be reused after removal, or must it be replaced at every service?
The body of the flange itself can usually be reused, but it is recommended to check the seal between the flange and the boiler neck upon repeated removal and replace it with a new one in case of visible wear, in order to maintain the tightness of the joint.

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

What is the maximum length of flue gas discharge 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 can cause a boiler fault message.

Why does water actually drip from the flue gas discharge?
A condensing boiler cools the flue gases enough that the water vapour they contain 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 through the condensate trap into the boiler's siphon; that is why all horizontal sections of piping have a prescribed slope toward the boiler or the trap.

Can 60/100 mm coaxial piping be combined with a separate Ø80/Ø80 system?
Yes, that is exactly the purpose of a splitter (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 discharge system?
It is recommended to use a certified system from the same manufacturer 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 discharge piping and condensate trap be inspected?
A visual inspection of joint tightness and condensate trap patency is recommended at least once a year, ideally during the regular service inspection of the boiler. For façade or roof terminals, it is also necessary to check that the terminal grille is not clogged with leaves, insects or snow.

Does the flue gas discharge need to be insulated?
When routed through heated spaces, insulation is usually not necessary, as the surface temperature of the coaxial piping is low. For longer sections routed through unheated spaces (attic, façade) or where there is a risk of moisture condensation on the pipe surface, additional insulation is recommended, especially at the condensate trap, to prevent freezing.

What happens if the flue gas discharge is undersized or too long?
If the maximum equivalent discharge length is exceeded or if there are leaks, the boiler usually reports a fault related to flue gas/air flow (fan fault, pressure switch fault, or flue gas path fault) and shuts 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 also be used in a cascade connection of multiple boilers?
For cascades with multiple boilers, a separate Ø80/Ø80 system with a common collecting chimney is usually used, or separate terminals for each boiler according to the cascade's project documentation. The specific components (extensions, elbows, splitters) are also compatible in this configuration, but the minimum terminal distances according to STN EN 15287 must be observed.

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

Does the condensate from the flue gas discharge need to be neutralised before being discharged into the sewer?
For typical family homes with a low-output boiler, neutralisation is usually not required due to the small amount of condensate and its dilution with other wastewater, but the applicable legislation and requirements of the local sewer operator must be followed. For higher outputs or boiler cascades, it is recommended to install a condensate neutralisation device before discharge into the public sewer.

Is the operation of a condensing boiler with this type of discharge noisier than with a classic chimney?
Forced draught (the boiler's fan) may be accompanied by slight operational noise, which is minimal when the route is correctly installed and mechanically secured (without freely vibrating sections of piping) and is generally comparable to or lower than the noise of a classic atmospheric boiler with chimney discharge.

Can the installation of this component be done by yourself, or is a professional required?
The mechanical connection of the components itself (plug-in system) is simple, but connecting the discharge to the condensing boiler, calculating the maximum route length and commissioning the boiler must be carried out by a person professionally qualified for the installation of gas appliances – this is both a manufacturer's 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 discharge route (many elbows, long route close to the limit), 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 the smallest necessary number of components is therefore also advisable from the point of view of operating economy.

Warranty

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