Duct electrical heaters for supply air heating in round duct ventilation system, with temperature controller, power demand from 0.6 up to 2.4 kW: temperature control knob with temperature range from -10°C up to +40°C on junction box front panel. Equipped with built-in temperature sensor integrated inside of heater's duct. Thermal switch with manual reset actuated at +60°C for the thermal overheating protection.

Power demand from 3.0 up to 9.0 kW: equipped with a triac power control unit. Power control is effected by means of switching ON/OFF the maximum load commutated by semiconductor device that is free of any mechanical wear parts. Load commutation starts at zero current and load to disable any magnetic field interferences.
Operation logic options:
* operation logic based on temperature sensor readings to maintain set air temperature in air duct;
* proportional electric heat control from 0 up to 100% with a 0-10 V control signal from the external controller.