Electric heaters are often used with mechanical type controller terminal units and are mounted on the discharge outlet. These units are typically VAV, Fan Powered Series/Parallel and Dual Duct boxes.
Electric heaters supply auxiliary heat, after the minimum preset primary air flow is met and additional heating is required to satisfy the space heat demands. During the heating cycle, the air volume will remain at the minimum setting. The selected minimum must be sufficient to provide the required heat transfer to satisfy space demand. It must also be sufficient to prevent nuisance cycling of the thermal cut-out.
Neptronic heaters provide all of the benefits of SCR control plus unique electronic airflow sensors for additional protection at low flows by constantly and accurately measuring air velocity and updating the heating output accordingly.