What application would a sail switch be used in?

What application would a sail switch be used in?

• A. Air flow sensing in supply duct system
• B. Temperature sensing in the return duct
• C. Humidity control in the evaporator
• D. Pressure regulation in the exhaust

Answer: (A)

A sail switch is a simple mechanical airflow sensor that uses a small vane (the “sail”) placed in the airstream. When air moves through the system, the vane deflects and triggers a switch to signal the control that there is adequate airflow. If airflow is insufficient, the vane won’t move enough to close the switch, and the system will not ignite or will shut down to prevent overheating or unsafe conditions. This makes it the appropriate choice for sensing air flow in the supply duct so the system only operates when proper airflow is present. It isn’t used for temperature sensing, humidity control, or pressure regulation in the exhaust, which is why those applications don’t fit.

A sail switch is a simple mechanical airflow sensor that uses a small vane (the “sail”) placed in the airstream. When air moves through the system, the vane deflects and triggers a switch to signal the control that there is adequate airflow. If airflow is insufficient, the vane won’t move enough to close the switch, and the system will not ignite or will shut down to prevent overheating or unsafe conditions. This makes it the appropriate choice for sensing air flow in the supply duct so the system only operates when proper airflow is present. It isn’t used for temperature sensing, humidity control, or pressure regulation in the exhaust, which is why those applications don’t fit.