1:10
Power modulation
SPA PLUS
Quick water heating function
106 %
High efficiency
SMART
Smart control
ATTACK Condensing KZT 25 is a wall-mounted gas condensing boiler with a built-in 60L DHW cylinder and intelligent control. The boiler achieves significant gas consumption savings thanks to continuous power modulation up to 1:10, and the Intelligent Combustion System ISC can operate even with a minimum power from 2.6-26 kW, making it a great choice for households with high DHW supply requirements. The boiler can also be controlled according to the outdoor temperature (weather-compensated regulation).
Suitable for every type of house or apartment
With the ATTACK KZT model series, it is possible to heat not only a family house but also a smaller business such as a (restaurant, smaller company, grocery store, etc.). In addition, the boiler offers DHW (domestic hot water) heating in a built-in 60L stainless steel cylinder in which a sufficient amount of hot water is immediately available. The KZT model is equipped with the SPA PLUS function, which increases DHW heating power in the cylinder to achieve the highest comfort. The boiler has a high power modulation ratio up to 1:10.
Gas boiler connection
To use a gas condensing boiler, it is necessary to have a natural gas connection, which belongs among the most ecological fuels among fossil fuels. For those who would like to have a condensing boiler even without a natural gas connection, there is a solution. The boiler can be connected to propane.
ATTACK Condensing KST 24 can be used for several types of gas (G20 natural gas or G31 propane; changing and setting the fuel must be performed by an service technician)
Why choose a gas boiler
Low acquisition cost of the device compared to biomass boilers or heat pumps – it belongs among the cheapest and least maintenance-demanding sources.
High power modulation
ATTACK Condensing KZT has a high range of power modulation up to 1:10. This is the main technical advantage of our gas boilers. This modulation system consists in the fact that the boiler can operate at low power, for example (starting from 2.4 kW). It achieves a high efficiency of up to 106% with energy class A for heating.
Quality and efficiency
In the production of boilers, we used brass components for the hydraulic assembly, ensuring maximum product reliability.
The new brass hydraulic group is equipped with:
- High-efficiency pump
- Three-way valve
- By-pass
- Flow regulator with filter
- Drain valve
- DHW temperature sensor
Technical data and documents for download
The ATTACK Condensing KZT gas condensing boiler achieves a high combustion efficiency of up to 106% with a power modulation of 1:10. High-quality components and processing guarantee a long service life. Find out more about other technical data.
- High power modulation 1:10
- High combustion efficiency 106%
- DHW heating in a built-in stainless steel cylinder
- Wide power range 2.6-26 kW
- Stainless steel exchanger
- Automatic heating water replenishment
- Frost and bacteria protection
- Brass hydraulic group of components
| Parameter | Unit | ATTACK Condensing KZT 25 |
| Max. thermal output of central heating | kW | 26 |
| Min. thermal output of central heating | kW | 2,6 |
| Max. thermal output of central heating (50/30 °C) / (80/60 °C) | kW | 27,2/25,1 |
| Min. thermal output of central heating (50/30 °C) / (80/60 °C) | kW | 2,7 |
| Gas connection pressure G20 | mbar | 20 |
| Gas connection pressure G31 | mbar | 37 |
| Emission class NOx | – | 6 |
| Volume of water in the boiler in central h. | l | 60 |
| Efficiency class by directive 92/42 EHS | – | A |
| D.H.W. flow Dt 30 °C | l/min | 16 |
| Stupeň ochrany | IP | IP X5D |
| El. voltage | V/Hz | 240/50 |
| El. input | W | 100 |
| Weight of the empty boiler | kg | 41,6 |
| Dimensions (W × H × D) | mm | 600×880×425 |
High-quality processing
All our products are manufactured with an emphasis on the selection of quality materials and the use of correct technologies and procedures. Brass components of the hydraulic assembly ensure maximum product reliability. Our own know-how is a guarantee of reliable service and long life.
Possibility of cascade connection
Condensing KZT boilers are designed to allow cascade connection of up to 4 boilers. For cascade connection, it is necessary to use a cascade controller, which can be purchased as an accessory. The cascade controller intelligently manages connected boilers and provides perfect control over the connected system.
Comfort with OpenTherm regulation
It is also possible to increase the comfort of a gas boiler using a regulator that will adjust the temperature according to the outdoor temperature. The temperature will thus automatically adapt to changes in the household and the outdoor temperature. This method of regulation can more effectively utilize the boiler’s power and at the same time save you money on operation.
In addition, you get greater comfort because the regulator takes care of everything for you. If, however, you want even more convenience, it will be provided by an additional control with OpenTherm two-way communication.
* the weather-compensated regulator is not part of the boiler delivery.
OpenTherm regulation (optional accessory)
The boiler allows connecting OpenTherm regulation, which can not only turn on the boiler but also detect the difference between actual room temperature and the set value, allowing boiler power modulation according to the thermal needs of the system. OpenTherm regulation guarantees lower consumption, more stable temperature, and greater comfort for the user. Get maximum comfort.
Smart remote control
ATTACK Condensing offers optional accessory OpenTherm room thermostat OT80 and Wifi modem OT81, with which you can control your boiler remotely via the ATTACK Condens mobile application.
Choose a service partner for installation
Creating a high-quality and prompt service network for our customers is very important to us. Our service partners provide prompt service assistance to every customer throughout the year.
