Johnson Controls W42AA-1 SPDT Humidity Controller 10-90% RH Range

The Johnson Controls W42AA-1 is a reliable SPDT (Single Pole Double Throw) humidity controller designed for precise humidity monitoring and control in commercial and industrial applications. This wall-mounted humidistat provides automatic humidity control within a 10% to 90% relative humidity range, making it ideal for HVAC systems, building automation, and environmental control applications.

Key Features:

• SPDT switching configuration for versatile control options
• Wide operating range: 10% to 90% relative humidity
• Adjustable setpoint allows precise humidity level control
• Durable construction for long-term reliability
• Wall-mountable design for easy installation
• Compatible with humidifiers, dehumidifiers, and ventilation systems

The W42AA-1 features a simple adjustment mechanism that allows facility managers and technicians to set the desired humidity level. When ambient humidity rises above or falls below the setpoint, the SPDT relay switches to activate connected equipment such as humidifiers, dehumidifiers, or ventilation fans. This controller is commonly used in warehouses, manufacturing facilities, greenhouses, museums, laboratories, and other environments where humidity control is critical for product quality, equipment protection, or occupant comfort.