How is the anticipator wired in regards to gas valve and thermostat contacts?

How is the anticipator wired in regards to gas valve and thermostat contacts?

• A. In Series With The R, W, And Y Contacts Of The Thermostat
• B. In Parallel With The R, W, And Y Contacts Of The Thermostat
• C. Across The Gas Valve Coil
• D. Across The Thermostat Sensor

Answer: (B)

The anticipator is a small resistance heater inside an electromechanical thermostat that provides a tiny, continuous heat bias to the thermostat’s sensing element. Its purpose is to cause the switch to open slightly sooner than the room actually reaches the setpoint, reducing overshoot and preventing short cycling. To work as intended, it must be wired in parallel with the thermostat contacts that control the gas valve. When heat is demanded and the thermostat closes, current flows through both the gas valve coil and the anticipator. The anticipator’s current heats its element, biasing the bimetal response so the contacts break contact a little earlier. If it were placed in series, it would drop voltage and hinder valve operation; if across the gas valve coil or across the sensor, it wouldn’t provide the proper parallel heating effect needed to influence the switching timing.

The anticipator is a small resistance heater inside an electromechanical thermostat that provides a tiny, continuous heat bias to the thermostat’s sensing element. Its purpose is to cause the switch to open slightly sooner than the room actually reaches the setpoint, reducing overshoot and preventing short cycling.

To work as intended, it must be wired in parallel with the thermostat contacts that control the gas valve. When heat is demanded and the thermostat closes, current flows through both the gas valve coil and the anticipator. The anticipator’s current heats its element, biasing the bimetal response so the contacts break contact a little earlier. If it were placed in series, it would drop voltage and hinder valve operation; if across the gas valve coil or across the sensor, it wouldn’t provide the proper parallel heating effect needed to influence the switching timing.