The purpose of a sequencer in an auxiliary 20 kW electric heater is to energize:

The purpose of a sequencer in an auxiliary electric heater is to ensure that the heating process is managed efficiently and safely. The correct answer indicates that the sequencer is designed to energize one or two heating elements along with the blower motor simultaneously, and then to activate the remaining heating elements in a timed sequence.

This approach allows the system to avoid excessive electrical load at startup by not turning on all heating elements at once. By staging the activation of the heating elements, the sequencer helps in controlling the overall energy consumption and maintaining a steady supply of warm air. Additionally, it allows the blower motor to start up and circulate air promptly, which ensures that the warm air is distributed effectively as the heater operates.

Staging in this manner protects the system from possible electrical overloads and promotes a smoother operational process, enhancing both efficiency and longevity of the components involved. The synchronization of the blower with the initial heating elements also contributes to a consistent and comfortable rise in temperature rather than potential hot spots or inefficiencies.