Product Overview & Application Area
The ROJEK KTP 25 is a manually fed solid fuel boiler with a nominal output of 25 kW for warm water central heating systems. It is designed for log wood and suitable lignite; other suitable biomass can be used within the respective fuel approval. The boiler is suitable for residential and commercially used buildings, provided that the heating load, system hydraulics, and chimney are matched to the output and operating conditions.
The KTP 25 operates without a fan and without electronic boiler control. Therefore, no electrical energy is required for the actual boiler operation. The design is thus suitable for heating systems where a robust, manually fed heat generator with mechanically controlled combustion is desired.
Technology & Equipment
The two-stage combustion principle combines a high gasification share with classic burn-off. Primary and secondary air can be regulated and adjusted to the fuel and the existing chimney draft. The KTP 25 has a combustion and filling chamber of 61.6 liters and accepts log wood up to 430 mm in length and up to 200 mm in diameter.
Several factory versions are available for adaptation to different installation situations. The door hinge is located on the right as standard and can be executed on the left as a factory option. The flue gas outlet is vertical as standard; a horizontal version is also possible as a factory option. Additionally, the flue pipe can be ordered with a cleaning opening in either vertical or horizontal execution. The desired version must be specified when ordering.
Everyday Advantages
The electricity-free boiler operation does without a fan and electronic boiler control. The adjustable combustion air, easily accessible cleaning areas, and manual fuel operation result in a manageable technical design. With log wood, the KTP 25 achieves an efficiency of 89.0% and boiler class 5; when operated with lignite, the efficiency is 87.5% and the boiler class is 4.
An integrated cooling loop enables the integration of a thermal safety device against overheating. The boiler can be integrated both into appropriately designed gravity systems and into heating systems with pump circulation.
System Integration & Compatibility
The required chimney draft for the KTP 25 is between 15 and 19 Pa. The flue pipe connection has a diameter of 160 mm. The minimum return temperature is 55 °C; for favorable continuous operation, a return temperature range of approximately 63 to 65 °C is intended.
As a reference value, a buffer tank of at least 1,000 liters is planned for the KTP 25. Buffer tank, return temperature boosting, pumps, expansion vessel, and safety devices must be sized according to the specific heating system. The KTP 25 can also be expanded with a suitable pellet burner system to create an automated pellet version.
Technical data at a glance
| Nominal output |
25 kW |
| Fuel |
Log wood, brown coal; other suitable biomass according to fuel approval |
| Combustion technology |
Two-stage combustion principle with gasification component |
| Efficiency |
89.0% firewood / 87.5% brown coal |
| Boiler efficiency class |
Class 5 firewood / Class 4 brown coal |
| Energy efficiency class |
A+ firewood / C brown coal |
| Max. firewood length |
430 mm |
| Combustion/fill chamber |
61.6 l |
| Water content |
109 l |
| Required chimney draft |
15–19 Pa |
| Flue gas temperature at rated output |
164 °C log wood / 169 °C brown coal |
| Flue pipe connection |
160 mm |
| Flue pipe outlet |
vertical standard / horizontal as factory option |
| Door hinge |
right standard / left as factory option |
| Heating water connection |
2 inches |
| Max. operating pressure |
2 bar |
| Max. operating temperature |
90 °C |
| Minimum return temperature |
55 °C |
| Recommended buffer tank |
at least 1,000 l |
| Dimensions W × D × H |
622 × 650 × 1,193 mm |
| Weight |
301 kg |
Installation
Installation, hydraulic connection, thermal safety devices, and flue gas connection must be carried out by appropriately qualified specialist personnel. When planning, particular attention must be paid to the required chimney draft of 15 to 19 Pa, the selected flue pipe routing, and sufficient clearance and maintenance space for the doors.
Notes
The desired door hinge side and flue pipe routing must be clearly specified when placing the order. The vertical flue gas routing and right-hand door hinge are the standard configuration. Horizontal flue pipe outlet, left-hand door hinge, and a cleaning opening on the flue pipe are factory options. For log wood operation, sufficiently dry firewood is required; low return temperatures or moist fuel can promote the formation of condensate, tar, and corrosion.
Scope of delivery
- ROJEK KTP 25 solid fuel boiler in selected factory version
- Operating and installation instructions
- Drain valve 1/2 inch
- thermostatic draft regulator RT3 or RT4, depending on the version
- Ash pan
- four leveling screws for boiler alignment
- side ceramic elements depending on the version
- upper ceramic elements to extend the flue gas path depending on the version