The differential in an automatic-changeover thermostat is _______.

The differential in an automatic-changeover thermostat is _______.

• A. the time interval between cycles
• B. the maximum temperature deviation allowed
• C. the difference between the cut-in and cut-out points of the thermostat
• D. the range between heating and cooling setpoints

Answer: (C)

In automatic-changeover controls, the thermostat uses a small temperature hysteresis to decide when to switch between heating and cooling. This hysteresis, called the differential, is the difference between the two switching temperatures—the cut-in point when the system turns on, and the cut-out point when it turns off. This gap sets how far the temperature must swing before the thermostat changes state, preventing rapid cycling. So the differential is specifically the difference between the cut-in and cut-out temperatures. The other ideas—cycle time, a maximum deviation, or the gap between the heating and cooling setpoints (the deadband)—describe related aspects but not this switching-range definition.

In automatic-changeover controls, the thermostat uses a small temperature hysteresis to decide when to switch between heating and cooling. This hysteresis, called the differential, is the difference between the two switching temperatures—the cut-in point when the system turns on, and the cut-out point when it turns off. This gap sets how far the temperature must swing before the thermostat changes state, preventing rapid cycling. So the differential is specifically the difference between the cut-in and cut-out temperatures. The other ideas—cycle time, a maximum deviation, or the gap between the heating and cooling setpoints (the deadband)—describe related aspects but not this switching-range definition.