Description
The Trane SWT3405 Air Pressure Sensing Switch it is a thermostatic expansion valve (TXV) employed in HVAC systems, in refrigerant circuits. The TXV optimizes the cooling capacity of the system, and its efficiency by controlling the superheat, the difference between the temperature of the refrigerant and that of the surrounding air by measuring air pressure. To achieve the required superheat with limited airflow, the TXV opens more when the pressure of the air in the evaporator coil is low, suggesting low airflow. However, the TXV restricts the flow of refrigerant in a bid to prevent overfeeding and the consequent freeze-up of the evaporator coil as the air pressure increases.
