Designed to control heating and prevent overheating of the heater and heated air at the outlet in purge heaters. Has a function of self-diagnostics of the heating device (serviceable - faulty), the sensor of control of movement of air. BSU performs the following functions:
- blocking the inclusion of the heating unit at an inlet air temperature higher than (22 ± 2) ° C;
- blocking the inclusion of the heating unit with a significant reduction in the amount of air supplied by the fan (more than 80%);
- restriction of air temperature at the outlet (over 60 ° С).
In case of failure of BSU, BN has additional protection against overheating (fuse). It is installed in heating devices in 220V power supply circuits. It is made in modifications of BSU-220 / 6A; BSU-220 / 15A; BSU-220 / 20A; BSU-220 / 40A depending on the nominal heat output of the heater. It is executed in the overall dimensions suitable for a concrete design.