Which valve is set at the adjustable heat anticipator on a gas thermostat?

• A. the gas pressure
• B. the amp flow reading of the control circuit
• C. the temperature of the room
• D. the water flow

Answer: (B)

The adjustable heat anticipator is used to mimic the electrical load of the gas valve coil so the thermostat accounts for the time lag between the thermostat calling for heat and the burner actually staying on. By setting the anticipator to draw a small current that matches the amp flow of the control circuit, the thermostat heats the internal sensor just enough to cause the contacts to open slightly earlier, reducing overshoot and short-cycling. So, the setting is based on the amp flow in the control circuit—the current the gas valve coil draws when energized. Gas pressure or water flow aren’t involved in this adjustment, and room temperature is what the thermostat senses, not what the anticipator simulates.