ATTACK KT elbow 45°, diameter 60/100, painted

Product detailed description

ATTACK KT elbow 45°, diameter 60/100, painted is part of the original flue gas exhaust and combustion air intake system ATTACK KT / KT PLUS, designed for wall-mounted condensing gas boilers ATTACK Condensing. This part belongs to the category: elbow 45°, diameter 60/100 mm, material galvanized steel with painted surface finish.

Closed combustion chamber and flue gas exhaust for 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 outward, also by forced draft provided by a fan built into the boiler. This closed circuit is solved in practice in two ways: 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 a separate system with two independent pipes. The coaxial version with a diameter of 60/100 mm is the most common solution for boilers up to approx. 35 kW, as it allows both the exhaust and intake to be routed through a single wall or roof penetration, is quick to install, and is aesthetically discreet.

Every element of the exhaust assembly – elbow, extension, condensate trap, chimney terminal and splitter – must be airtight, resistant to flue gas temperatures as well as to the condensate generated in large quantities during operation of a condensing boiler, precisely because the boiler is able to utilize the latent heat of water vapour from the flue gases. This condensate is exactly why the ATTACK KT system cannot be safely replaced with a common chimney part intended for atmospheric boilers – such parts are not designed for permanent contact with acidic condensate nor for the correct slope that directs condensate back to the boiler or to the trap.

Elbow – change of exhaust route direction

Elbows are used wherever the piping direction needs to be changed – most commonly from the horizontal boiler outlet to a vertical riser towards the roof, or conversely when exiting through a side facade. The 90° version is used for a right-angle change of direction (typically right after the boiler or just before the roof/wall penetration), while the 45° elbow is chosen where a milder change of direction is sufficient and it is desirable to reduce pressure loss compared to a sharp 90° elbow, or to bypass an obstacle (a beam, another installation's pipe).

Every elbow increases the resistance to flow of both flue gases and intake air, therefore the equivalent length of the elbow is taken into account when designing the route (added to the total allowed exhaust length), and it is recommended to use the smallest possible number of elbows needed for the given room layout.

Direction change angle: 45°.

Example of a typical connection in a real installation:
boiler → 90° elbow → vertical extension → chimney through the roof (or: boiler → 45° elbow → angled section along the roof truss → 45° elbow → continuing vertically).

Step-by-step installation procedure

1. Check the maximum allowed equivalent route length in the boiler manual and include the equivalent length of this elbow in the total sum.
2. Fit the elbow in the direction of flow according to the marking on the part, check the orientation relative to adjoining parts.
3. Seal and mechanically secure the joint so that the elbow cannot rotate on its own during operation.
4. If combining multiple elbows in series, continuously check that the sum of equivalent lengths does not exceed the boiler's limit.
5. After connecting the entire route, check the tightness of all joints.

Material and construction

This part is made of galvanized steel with an additional painted surface finish, which increases resistance to weather conditions for the exterior part of the route (for example, the chimney terminal on the roof) and at the same time gives the part an aesthetic, uniform appearance matching the design of ATTACK Condensing boilers. The surface finish resists the normal temperatures of flue gases from a condensing boiler and short-term contact with condensate, provided the pipe has the correct slope, which ensures that condensate does not stay in the part for a long time.

System category: coaxial (concentric). Version: 45° direction change.

Compatibility with ATTACK boilers

Part PR41 is intended for the connection system common to the entire range of ATTACK wall-mounted condensing boilers 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 connection port and the maximum allowed exhaust route length in the installation manual for the specific boiler model, as this may vary slightly depending on boiler output (20, 28 or 48 kW for the KT range).

Installation and warnings

Elbows are fitted in the direction of flow according to the marking on the part (arrow or diagram in the manual), and the joint is secured so it cannot rotate during operation. When using multiple elbows in series (e.g. 2× 45° instead of 1× 90°), their equivalent lengths add up and must be taken into account when calculating the maximum allowed route length.

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

Standards and safety requirements

Installation of flue gas exhausts 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 minimum distances of the terminal from windows, ventilation openings, neighbouring plots and ground level, as well as the minimum height of the terminal above the roof plane. The boiler itself and its exhaust 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 qualified to install and service gas appliances, who, upon completion, issues an inspection report or commissioning protocol. In case of any change to the route compared to the original approved design (e.g. additional route extension, change in the number of elbows), it is necessary to check whether the boiler is still 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

When correctly installed, elbows do not require special maintenance; during a service inspection, it is only recommended to visually check the tightness of the joint and that the part has not rotated from its original position during operation.

The recommended inspection interval for the entire exhaust 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 part is also checked, as well as the patency of the condensate path and the overall condition of the joints along the entire route from the boiler to the outdoor terminal.

Typical usage scenarios

Scenario 1 – change from horizontal boiler outlet to vertical riser: the boiler outlet exits sideways, a 90° elbow right after the boiler directs the route upward towards the roof.

Scenario 2 – bypassing an obstacle in the route (ceiling beam, another pipe): instead of one sharp elbow, two elbows with a milder angle are used, which deflect the route around the obstacle and then return it to its original direction.

Related parts in the ATTACK KT range

The 45° elbow is a milder alternative to the 90° elbow PR40 – for the same change of direction (e.g. 90°), two 45° elbows can be used instead of one 90° elbow, which in some cases achieves smoother flow; however, a higher combined equivalent length of the two parts compared to a single one must be taken into account.

A complete overview of all parts of the ATTACK KT / KT PLUS flue gas exhaust 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 exhausts, flue pipes > accessories by brand > Attack on this e-shop.

Summary

ATTACK KT elbow 45°, diameter 60/100, painted (code PR41) is a part of type elbow 45° 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: 45° direction change. The part is intended 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 exhaust parts available on this e-shop, allowing you to assemble a complete flue gas exhaust route exactly according to the layout of your specific installation.

Frequently Asked Questions

Can two 45° elbows (PR41) be used instead of one 90° elbow?
Yes, two 45° elbows connected in series in opposite directions create a so-called offset, which can be used to bypass an obstacle while maintaining the original route direction, or to replace one 90° elbow with a milder angle and theoretically lower pressure loss – however, their combined equivalent length must be taken into account when calculating the maximum route length.

Is the 45° elbow also suitable for connecting a vertical and a slightly slanted section along a rafter?
Yes, the mild 45° angle is often used precisely to bypass roof rafters or other structural elements, where a sharp 90° elbow would mean an unnecessarily large change of direction and higher pressure loss.

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 draft – they draw combustion air from outside and discharge flue gases through their own exhaust system (coaxial 60/100 mm or separate Ø80/Ø80). A masonry chimney is therefore not needed; a wall or roof penetration for the plastic-aluminium piping is sufficient.

What is the maximum flue gas exhaust length for 60/100 mm coaxial piping?
The exact value depends on the specific boiler model (ACKT20, ACKT28, ACKT48, KST24 or KZT25) and is stated in the installation manual – typically an equivalent length of 10–15 m, where a 90° elbow counts 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 the boiler to report a fault.

Why does water actually drip from the flue gas exhaust?
A condensing boiler cools flue gases so much that the water vapour contained in them condenses – it is precisely from this additional heat that the boiler gains its high efficiency. The resulting condensate is slightly acidic and must be discharged via a condensate trap into the boiler's siphon; that is why all horizontal pipe sections have a prescribed slope towards the boiler or the trap.

Can 60/100 mm coaxial piping be combined with a separate Ø80/Ø80 system?
Yes, that is exactly what a splitter (e.g. PR51, PR51A or PR51B) is for, which splits one 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 parts of different diameters or from another manufacturer with the ATTACK exhaust system?
It is recommended to use a certified system from the same manufacturer, as stated in the manual for the specific boiler (for ATTACK Condensing boilers this is the ATTACK KT/KT PLUS system). Combining parts of different diameters, materials, or from other manufacturers may cause leaks, improper condensate drainage, and loss of the boiler warranty.

How often should the exhaust piping and condensate trap be checked?
A visual check of joint tightness and the patency of the condensate trap is recommended at least once a year, ideally during a regular boiler service inspection. For facade 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 exhaust need to be insulated?
When routed through heated space, insulation is usually not necessary, as 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 location of the condensate trap, to prevent it from freezing.

What happens if the flue gas exhaust is undersized or too long?
If the maximum equivalent exhaust length is exceeded or in case of leaks, the boiler usually reports a fault related to flue gas/air flow (fan fault, pressure switch fault or flue path fault) and shuts down for safety reasons. The solution is to recalculate the route according to the manual and make adjustments if needed (shorter route, fewer elbows, or switching to a separate Ø80/Ø80 system).

Can this part 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 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 parts I need for my installation?
The most reliable way is to consult the installation manual for the specific boiler model (ACKT20/28/48, KST24, KZT25), which contains diagrams of typical connections and maximum allowed lengths. For a more complex or non-standard layout (long route, penetration through multiple floors, cascade), we recommend consulting an installation company or directly the seller before ordering the exact number of pieces.

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

Is operation of a condensing boiler with this type of exhaust noisier than with a classic chimney?
Forced draft (from the boiler's fan) may be associated with slight operational noise, which, with a correctly installed and mechanically secured route (without freely vibrating pipe sections), is minimal and usually comparable to or lower than the noise of a classic atmospheric boiler with a chimney exhaust.

Can this part be installed by yourself, or is a professional required?
The mechanical connection of the parts (plug-in system) itself is simple, but connecting the exhaust 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's condition and a legal requirement for maintaining the warranty and safe operation.

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

Warranty

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