ROJEK KTP 25 natural draft boiler for firewood – 25 kW
The ROJEK KTP 25 is a hand-fed natural draft boiler for firewood with a nominal output of 25 kW.
The boiler operates without a fan, relying solely on natural chimney draft, and is suitable for reliable heat supply
for single-family homes, agricultural buildings, or smaller commercial units.
Important: The boiler is occasionally referred to as a wood gasifier. Technically, however, it is a
classic firewood natural draft boiler. Combustion occurs via natural chimney draft and
is mechanically controlled by air flaps and a thermostatic draft regulator.
This allows the KTP 25 to operate with simple, robust, and durable heating technology.
Highlights
- ⭐ Natural draft boiler for split logs without combustion fan
- ⭐ 25 kW heating output for residential buildings and smaller commercial properties
- ⭐ Robust welded steel construction
- ⭐ Thermostatic draft regulator for automatic output control
- ⭐ EN 303-5 certified solid fuel boiler
Application area & target group
The ROJEK KTP 25 is suitable for buildings with medium heat demand. Typical applications include:
- Single-family houses and larger residential buildings
- Workshops and agricultural buildings
- Renovation projects with existing chimney system
- Wood heating systems in combination with buffer tanks
Naturally seasoned log wood is used as fuel. For efficient combustion, a
wood moisture content of no more than 20% is recommended.
Everyday advantages
Thanks to the simple natural draft principle, the boiler operates without complex electronics or fan technology.
This makes the heating technology particularly robust, durable, and low-maintenance.
The generously sized combustion chamber allows for longer burn times and reduces the number of reloading intervals
in daily heating operation.
Technology & equipment
The boiler consists of a sturdy welded steel construction with a water-cooled grate.
Combustion takes place via natural draft through the chimney draft.
- adjustable primary and secondary air
- thermostatic draft regulator RT3
- integrated pressure gauge and thermometer
- integrated cooling loop for overheating protection
- Connection flow / return G 2"
The recommended chimney draft is approximately 8–12 Pa.
Efficiency & Environment
The boiler meets the requirements of the European standard EN 303-5 for solid fuel boilers.
- Efficiency: approx. 75%
- Energy efficiency class: A+
- Flue gas temperature at rated output: approx. 220–300 °C
For efficient and low-emission operation, the use of a buffer tank is recommended.
Technical data
| Manufacturer |
ROJEK |
| Model |
KTP 25 |
| Boiler type |
Log wood natural draft boiler |
| Nominal output |
25 kW |
| Minimum output |
15 kW |
| Combustion chamber volume |
61.6 liters |
| Water volume |
109 liters |
| Max. log length |
43 cm |
| Flue pipe diameter |
159 mm |
| Max. operating pressure |
2 bar |
| Max. operating temperature |
90 °C |
| Weight |
301 kg |
| Energy efficiency class |
A+ |
Scope of delivery
- ROJEK KTP 25 boiler
- Operating instructions
- Thermostatic draft regulator RT3 with chain
- Heating outlet valve 1/2"
- Side ceramics
- Alignment screws
Installation and safety instructions
Installation must be carried out by a qualified heating contractor.
The connection of a safety group and a correctly installed cooling loop is required.
Only dry split logs may be used as fuel.
The use of liquid fuels for lighting the fire is not permitted.
FAQ
Is the ROJEK KTP 25 a wood gasifier?
No. The KTP 25 operates as a classic natural draft boiler for split logs and not according to the wood gasification principle.
Does the boiler require electricity?
Not for the boiler operation itself. Electricity is only needed for the heating circulation pump.
What length of wood can be used?
The maximum split log length is about 43 cm.
Is a buffer tank necessary?
Technically not strictly required, but recommended for efficient operation.
What chimney draft is required?
The recommended chimney draft is between 8 and 12 Pascal.
What wood moisture content is optimal?
A residual moisture content between 12% and 20% is recommended.
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