ATTACK PLUS vertical separator diameter 60/100 - diameter 80/80, AL/PP

Product detailed description

ATTACK PLUS vertical splitter diameter 60/100 - diameter 80/80, AL/PP 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 component belongs to the category: splitter – vertical design (PLUS series), diameter 60/100 mm → 80/80 mm, material aluminium (AL) on the exhaust branch, polypropylene (PP) on the intake branch.

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 likewise by forced draught, provided by a fan built into the boiler. In practice, this closed circuit is solved in two ways: by coaxial (concentric) piping, where a smaller pipe for air intake runs inside a larger pipe and the annular space serves for flue gas exhaust, or by a separate system with 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, since it allows both exhaust and intake to be routed through a single wall or roof penetration, is quick to install and visually unobtrusive.

Every element of the exhaust assembly – elbow, extension, condensate trap, chimney terminal and splitter – must be tight, resistant to flue gas temperatures as well as 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 the water vapour contained in the flue gases. This condensate is exactly 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 returns condensate back to the boiler or to the trap.

Since this component connects both systems, it is simultaneously subject to the rules of coaxial ducting (on the side connecting to the boiler) and of the separate Ø80/Ø80 system (on the side of the continuing branches) – see also the explanation below in the section on the separate system.

At higher outputs or with more complex exhaust routes (longer runs, more changes of direction, a shared chimney flue for several boilers), the 60/100 mm coaxial pipe can no longer be used efficiently – flow resistance would be too high and the boiler's output would be restricted. For these cases, a transition is therefore made to a separate (twin-pipe) system with a diameter of 80 mm, where air intake and flue gas exhaust are routed through two independent pipes, which may even follow different routes (for example flue gas exhaust above the roof and air intake through a side wall). This system is referred to in technical terminology as Ø80/Ø80 or C83/C93, depending on the type of termination, and is common with boiler cascades, higher-output boilers, or wherever a greater distance to the façade or roof needs to be covered.

Components of the separate ATTACK KT system with an 80 mm diameter are made of polypropylene (PP) – a material that is durably resistant to the acidic condensate produced during flue gas condensation, has low weight and a low coefficient of friction, which reduces pressure losses on longer runs. Since these are separate pipes, both (exhaust and intake) must be routed with the same slope and the same logic as coaxial piping – flue gases must not accumulate in horizontal sections, and condensate must always drain by gravity back towards the boiler or into the trap.

Splitter – transition from coaxial to separate system

The splitter is a component that divides a single 60/100 mm coaxial pipe coming from the boiler into two independent 80 mm pipes – one for flue gas exhaust and the other for combustion air intake. It is used wherever a longer route needs to be covered than the coaxial pipe alone allows, or where intake and exhaust need to be routed along different paths (for example exhaust above the roof and intake through the side wall of the plant room).

The "vertical/horizontal" (universal) design can be installed in either position depending on the requirements of the specific installation, while the "vertical" design is intended exclusively for vertical installation directly behind the boiler, from which two independent vertical (or subsequently deflected) branches continue. The aluminium/aluminium material combination is used where the intake branch is also routed through metal piping (for example due to a requirement for greater mechanical resistance of the route), while the aluminium/PP combination is more common – the exhaust (flue gas) branch remains aluminium and the intake branch switches to lighter polypropylene.

Example of a typical connection in a real installation:
boiler → flange → splitter 60/100 → 80/80 → independent flue gas branch (Ø80) above the roof + independent intake branch (Ø80) through a side wall.

Step-by-step installation procedure

1. Fit the splitter directly behind the boiler outlet (or behind the flange), check the correct orientation according to the design (vertical/horizontal, or vertical only for the PLUS vertical type).
2. Plan the routes of both branches (exhaust and intake) so that each individually complies with the maximum length specified in the boiler manual.
3. Connect further components (pipes, elbows, chimney terminal) to the exhaust branch, maintaining a minimum slope of 3° towards the boiler.
4. Connect the intake branch, check that its outlet is not located in close proximity to the exhaust outlet (risk of flue gas being drawn back in).
5. After connecting both branches, check the tightness of all joints on the splitter and the connected components.

Material and construction

The splitter combines two materials according to the requirements of the individual branches: the exhaust (flue gas) branch remains aluminium, since it is in direct contact with hot flue gases and must withstand higher temperatures at boiler start-up, while the intake branch switches to lighter polypropylene, which is sufficient for conveying cold combustion air and reduces the overall weight and cost of the component.

System classification: transition from coaxial to separate system (splitter). Design: vertical only.

Compatibility with ATTACK boilers

The PR51A component is intended for the connection system common to the entire range of wall-mounted condensing boilers ATTACK ACKT20, ACKT28 and ACKT48 (Condensing KT series), 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 exhaust route length, as this may vary slightly depending on the boiler's output (20, 28 or 48 kW for the KT series).

Installation and warnings

The splitter is installed directly behind the boiler outlet (or behind the flange), and it should already be taken into account when planning the route that two independent branches continue from this point onward, each with its own length limits according to the boiler manual. When installing the universal design horizontally, check the manufacturer's manual for the permitted orientation, so as not to impair condensate drainage from the exhaust branch.

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

Standards and safety requirements

Installation of flue gas exhaust for condensing boilers in Slovakia is governed primarily by standard STN EN 15287 (Chimneys – Design, installation and commissioning of chimneys – Part 1: Chimneys for fan-assisted appliances), which sets out 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 comply with the requirements of STN EN 483 (type C gas boilers) and be installed in accordance with the applicable technical operating regulations for gas appliances.

Installation may only be carried out by a person qualified for the installation and servicing of gas appliances, who, upon completion, issues an inspection report or commissioning protocol. In the event of any change to the route compared with 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 is still 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

During a service inspection of the splitter, the tightness of both outlet joints is checked, as well as whether unwanted condensation forms at the branching point outside the intended drainage path – especially at the transition from the metal to the plastic branch, where the materials may have different thermal expansion.

The recommended inspection interval for the entire exhaust route is once a year, usually as part of the regular boiler service carried out by an authorised 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 outdoor terminal.

Typical usage scenarios

Scenario 1 – long route exceeding the coaxial pipe limit: the distance from the boiler to the façade or roof exceeds the maximum permitted length for 60/100 mm, so the splitter converts the route right behind the boiler to a separate Ø80/Ø80 system with lower pressure losses.

Scenario 2 – intake and exhaust need to be routed in different directions: the building layout requires flue gases to be discharged above the roof, while combustion air is drawn in through the side wall of the plant room – the splitter allows both branches to be routed completely independently.

Related components in the ATTACK KT range

The vertical PLUS design of the splitter is complemented in the range by the universal design PR51 (same AL/PP material mix, but also horizontal installation) and the fully aluminium universal design PR51B. For an installation that is clearly vertical from the outset, PR51A is the simplest and most cost-effective choice.

A complete overview of all components 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 exhausts, flue pipes > brand accessories > Attack on this e-shop.

Summary

The ATTACK PLUS vertical splitter diameter 60/100 - diameter 80/80, AL/PP (code PR51A) is a component of type splitter – vertical design (PLUS series) with diameter 60/100 mm → 80/80 mm made of aluminium (AL) on the exhaust branch, polypropylene (PP) on the intake branch, belonging to the transition from coaxial to separate system (splitter). Recommended installation orientation: vertical only. The component is intended for boilers ATTACK ACKT20, ACKT28 and ACKT48 (Condensing KT series), ATTACK KST24 (Condensing KST) and ATTACK KZT25 (Condensing KZT), and is part of the wider range of ATTACK KT exhaust components available on this e-shop, allowing a complete flue gas exhaust route to be assembled exactly according to the layout of a specific installation.

Frequently Asked Questions

Why choose the vertical design of the PR51A splitter instead of the universal PR51?
If the installation is clearly predetermined (boiler with a vertical outlet, both branches continuing upward), the vertical design of the PR51A PLUS series can be a structurally simpler and cheaper solution, since it does not need to be designed for universal use in both positions like the PR51.

Can the PR51A be subsequently turned to a horizontal position if the route requirements change?
The PR51A is structurally designed exclusively for vertical installation, so if requirements change to horizontal routing, it is recommended to replace it with the universal design PR51, which is certified for both installation positions.

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 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 length of flue gas exhaust for a 60/100 mm coaxial pipe?
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, 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 trigger a boiler fault message.

Why does water actually drip from the flue gas exhaust?
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 gains 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 towards the boiler or the trap.

Can a 60/100 mm coaxial pipe be combined with a separate Ø80/Ø80 system?
Yes, that is exactly what a splitter (e.g. PR51, PR51A or PR51B) is for – it divides a single coaxial pipe from the boiler into two independent Ø80 mm pipes. It is used for longer routes or when intake and exhaust need to be routed in different directions.

Can components of different diameters or from a different manufacturer be combined with the ATTACK exhaust 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 exhaust piping and condensate trap be checked?
A visual check of the tightness of the joints and the patency of the condensate trap is recommended at least once a year, ideally during the boiler's regular service inspection. For a façade or roof terminal, it should also be checked that the terminal grille is not blocked by leaves, insects or snow.

Does the flue gas exhaust need to be insulated?
When the exhaust is 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, façade) or where there is a risk of moisture condensing on the pipe surface, additional insulation is recommended, especially at 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 there are leaks, the boiler will typically report a fault related to flue gas/air flow (fan fault, pressure switch or flue path fault) and shut down for safety reasons. The solution is to recalculate the route according to the manual and make any necessary adjustments (shorter route, fewer elbows, or a switch to the separate Ø80/Ø80 system).

Can this component also be used in a cascade connection of several boilers?
Cascades with multiple boilers typically use a separate Ø80/Ø80 system with a shared collecting flue, or separate terminals for each boiler according to the cascade's design documentation. The specific components (extensions, elbows, splitters) are also compatible in this arrangement, but minimum distances between terminals must be maintained according to STN EN 15287.

How do I find out exactly which components I need for my installation?
The most reliable approach is to refer to the installation manual for the specific boiler model (ACKT20/28/48, KST24, KZT25), which contains diagrams of typical connections and maximum permitted lengths. For a more complex or non-standard layout (long route, penetration through several 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 exhaust need to be neutralised before being discharged into the sewer?
For typical family houses with a low-output boiler, neutralisation 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 operator must be observed. 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 exhaust noisier than with a classic chimney?
Forced draught (from the boiler's fan) may be accompanied by a slight operating noise, which, however, with a correctly installed and mechanically secured route (without freely vibrating sections of piping), is minimal and generally comparable to or lower than the noise of a classic atmospheric boiler with chimney exhaust.

Can the installation of this component be handled independently, or is a professional required?
The mechanical connection of the components themselves (plug-in system) 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 for the installation of 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 exhaust route (many elbows, a 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 reduce its output or report a fault. Designing the route with as few components as necessary is therefore also advisable from the point of view of operating economy.

Warranty

This ATTACK exhaust 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. In the event of a claim, we recommend keeping the proof of purchase and, if necessary, photographic documentation of the installation method, since with exhaust systems the functionality is closely linked to the correctness of the installation (compliance with the slope, maximum route length and distances according to the manual).