Which components are commonly controlled by electromechanical thermostats?

Which components are commonly controlled by electromechanical thermostats?

• A. Only the heating element.
• B. Fans and compressors not including heaters.
• C. Compressors, condenser fan motors, evaporator fan motors, heaters and reversing valve solenoids.
• D. Humidity control system.

Answer: (C)

Electromechanical thermostats act as the switching brains that turn major HVAC components on and off based on the room temperature. They drive relays or contactors that power the equipment, so they commonly control the outdoor compressor and condenser fan motor for cooling, the indoor evaporator (blower) fan motor for both heating and cooling, any electric heating elements, and the reversing valve solenoids in heat pump systems to switch between heating and cooling modes. Humidity control systems are typically handled by a separate humidistat or control, not by the basic thermostat. Limiting control to only the heating element misses the cooling and fan operations these thermostats also manage, making the set that includes compressors, condenser and evaporator fans, heaters, and reversing valve solenoids the best fit.

Electromechanical thermostats act as the switching brains that turn major HVAC components on and off based on the room temperature. They drive relays or contactors that power the equipment, so they commonly control the outdoor compressor and condenser fan motor for cooling, the indoor evaporator (blower) fan motor for both heating and cooling, any electric heating elements, and the reversing valve solenoids in heat pump systems to switch between heating and cooling modes. Humidity control systems are typically handled by a separate humidistat or control, not by the basic thermostat. Limiting control to only the heating element misses the cooling and fan operations these thermostats also manage, making the set that includes compressors, condenser and evaporator fans, heaters, and reversing valve solenoids the best fit.