Which component is NOT directly operated by low voltage thermostats?

Low voltage thermostats are designed to control various HVAC components by sending signals to either energize or de-energize them. The primary function of a thermostat is to maintain the desired temperature in a space by monitoring the ambient temperature and activating or deactivating heating or cooling systems as needed.

Heat pumps, which serve as systems for both heating and cooling by transferring heat, typically operate on higher voltage levels than those that low voltage thermostats can directly manage. Instead, low voltage thermostats will usually control components such as contactors, relays, and solenoids, which can directly interact with the high voltage circuits required by the heat pump's compressor and other integral components. Therefore, while a thermostat can signal these other components, the heat pump itself is not directly operated by the low voltage thermostat.

This distinction is important because it reflects how different components interact within the HVAC system and the role of voltage levels in these interactions.