Compact II TOP gas radiant tube

Gas radiant tube with extremely high radiant efficiency. Efficient solution with a unique pressure burner system with even temperature distribution.
icon New overpressure burner
icon Isolated reflector
  • Seasonal heating energy efficiency 93%
  • High radiant efficiency of 80.7% (usually 65%)
  • New overpressure burner
  • Quick and easy installation
  • Heat resistant thin tubes
  • Integrated reflector insulation
  • Flue gas temperature modulation, two-stage output
  • Expansion joints every 2 m, protected by a utility model
  • Special structured aluminum reflector with high reflectivity
  • Connector for local or central control connection
  • Device status sensor connector
  • Free commissioning
  • Extended warranty up to 7 years based on contract

New pressure burner

In COMPACT2 we use a brand new overpressure burner, developed specifically for this innovative infrared radiator. Generally speaking, overpressure burners have a very high combustion efficiency but a short flame. With our technical solution, we managed to stretch the flame to an even greater length than the previous model. As a result, the temperatures of the radiation tubes are evenly distributed and there is no overheating in the first two meters behind the burner box.



Easy installation

The gas radiant tube is delivered right from the Lersen production plant in individual segments 2m in length, already completely assembled. Therefore, the assembly itself is very simple: you just need to assemble them together and connect with six screws.



MOM – DAD Dilatation

COMPACT2 uses a unique dilatation system developed at Lersen. It is a system we familiarly call “MOM <-> DAD”. The radiation tubes are equipped with very precisely turned flanges, which are welded to the radiation tube. The “MOM” flange is firmly attached to the segment face and the “DAD” flange is loose. When the radiating tubes start to expand due to the heat, the “DAD” flange slides into the “MOM” flange. The dilatation therefore takes place inside the radiation tubes and does not affect the design of the device. Infrared heaters are therefore not deformed by heat and always remain dimensionally stable.



Isolated reflector

Only the TOP version uses an insulated reflector, made as a sandwich. From the upper side, the insulation is covered with a 0.8 mm thick galvanized sheet metal to emphasize the aesthetic part of the radiant tube and at the same time serves as a structural element that strengthens the reflector. Inside, Rockwool mineral wool with a thickness of 40 mm with a temperature resistance of 300 °C is used. The inner reflecting surface of the reflector is made of aluminum sheet, which has the highest heat-reflecting ability of all materials and at the same time its surface is structured so that we can reflect radiance as efficiently as possible, especially from the upper parts of radiation tubes.




The electronics in the new COMPACT2 gas radiant tube keep the burner fan running at minimum speed after the heating has been switched off, thus preventing the direction of the draft from rotating. The hot air, heated by the accumulated heat from the radiation tubes, therefore still flows from the burner to the flue and the energy is gradually sent into the hall without uselessly escaping by suction to the exterior. The whole system is controlled by a temperature sensor in the flue gas, so the time for HEATENDING can vary and is determined by the speed at which the residual heat is sent to the hall.


Flue gasses tend to condense inside bulky or massive gas heaters before they reach operating temperature. This typically occurs after a night or weekend attenuation, when the heater and the hall are cold. Lersen’s ANTI-CONDENSATION system can effectively prevent condensation in the radiant tubes by not allowing the burner to switch off until the device warms up to operating temperature, helping to extract any condensate, but it has little effect on eliminating condensate in long uninsulated or coaxial flues.

Seasonal energy efficiency % 89,9 90,6 90,6 90,6
Rated power input – G20 Nom. | Min. kW 19 | 14 37 | 28 49 | 34 49 | 39
Rated power – G20 Nom. | Min. kW 17,5 | 12,7 33,7 | 25,5 44,6 | 30,9 44,6 | 35,5
Combustion efficiency LCV Nom. | Min. % 92 | 90,5 92 | 90,5 92 | 90,5 92 | 90,5
Transmitted power – G20 Nom. | Min. kW 15,2 | 11,2 29,9 | 22,6 39,5 | 27,4 39,5 | 31,5
Radiation efficiency % 80 80 80 80
Value NOx mg/kWh 165 165 165 165
Electric burner box cover | other IP 40 | 00 40 | 00 40 | 00 40 | 00
Natural gas consumption Nom. | Min. m3/hod 1,8 | 1,3 3,5 | 2,7 4,7 | 3,2 4,7 | 3,7
Weight kg 119 167 214 262