In thermostat-controlled equipment, the differential is defined as the difference between the temperature at which the switch turns the burners on and the temperature at which the switch turns the burners off.

In thermostat-controlled equipment, the differential is defined as the difference between the temperature at which the switch turns the burners on and the temperature at which the switch turns the burners off.

• A. Temperature at which the switch turns the burners on and the temperature at which the switch turns the burners off
• B. Temperature setpoint minus actual room temperature
• C. The average of the high and low limit temperatures
• D. The outdoor temperature and indoor temperature

Answer: (A)

Differential refers to the temperature range the thermostat uses to switch the burner on and off. The burner turns on when room temperature falls to a lower threshold, and it turns off once the temperature climbs to a higher threshold. That gap between the on point and the off point is the differential. It’s the mechanism that prevents constant on/off cycling and helps balance comfort with energy use. For example, with a setpoint of 70°F and a differential of 2°F, heating would come on around 68°F and turn off around 70°F, creating a 2°F band. The other options describe either how far the current temperature is from the setpoint, an average of limits, or indoor vs outdoor temperatures, none of which define the switching thresholds the differential represents.

Differential refers to the temperature range the thermostat uses to switch the burner on and off. The burner turns on when room temperature falls to a lower threshold, and it turns off once the temperature climbs to a higher threshold. That gap between the on point and the off point is the differential. It’s the mechanism that prevents constant on/off cycling and helps balance comfort with energy use.

For example, with a setpoint of 70°F and a differential of 2°F, heating would come on around 68°F and turn off around 70°F, creating a 2°F band. The other options describe either how far the current temperature is from the setpoint, an average of limits, or indoor vs outdoor temperatures, none of which define the switching thresholds the differential represents.