RT3/2 is used to heat passenger areas in trams. RT3/2A is used to heat passenger areas in trolley buses Both heaters are mounted under passengers’ seats

The heater consists of a heating element, two fans and electronic regulator with contactless temperature sensor and safety-fuse. The electronic regulator functions through output contact relay and external contactor for output air, where the temperature does not exceed 60°C. The regulator further ensures slowing down of the fan after the heater is switched off and decreases amount of air when the temperature drops below 40°C. The heater is controlled by a signal to the regulator. The regulator a zero input when the heater is not operating. In case of fan failure or regulator, the maximum cover temperature is limited to a maximum of 80 °C.

The heater cover is made from steel sheet protected against corrosion by means of powder painting. The color of the painting is applied in accordance with the requirements of the user.

The heater is connected to the external circuits with the help of self-tightening clamps, which are accessible after removing the side cover provided with safety screws. The cover is provided with two GP21 and GP16 bushings to connect power and controlling cables.