Which contacts on sequencers must conduct the most current?

The option regarding heating element contacts is correct because these contacts are specifically designed to handle and conduct the highest levels of current in a heating system. Heating elements, such as those found in electric furnaces or heat pumps, require significant electrical energy to generate the necessary heat for space heating.

Power contacts are also involved in conducting current, but they primarily serve to deliver power to the heating element contacts rather than directly handling the current needed for heating. Low-voltage contacts deal with lower current levels, as they are typically associated with control circuits, which work at reduced voltages for safety and functionality. Control contacts similarly manage control signals and operate at lower current loads.

Therefore, when it comes to which contacts must conduct the most current, heating element contacts are the clear choice, as they directly connect with the heating elements responsible for producing heat and require the capacity to manage higher electrical loads.