Johnson Controls W42AA-1 Humidistat, Line/Low Voltage, 10-90% RH, SPDT

Description

The Johnson Controls W42AA-1 is a versatile humidistat engineered for reliable humidity sensing and control in both line voltage and low voltage HVAC applications. With a broad 10 to 90% relative humidity (RH) sensing range and a tight 4% RH differential, this control delivers accurate, responsive performance to help maintain comfortable and healthy indoor environments.

Key Features

• Wide sensing range of 10 to 90% relative humidity (RH)
• 4% RH differential for precise, stable humidity control
• Compatible with both line voltage and low voltage systems
• SPDT (Single-Pole, Double-Throw) contact configuration for flexible switching applications
• Suitable for residential, commercial, and light industrial HVAC installations

Application

The W42AA-1 humidistat is ideal for controlling humidifiers, dehumidifiers, ventilation systems, and other humidity-sensitive HVAC equipment. Its SPDT contact design allows it to be wired for either humidification or dehumidification control, providing maximum installation flexibility. The dual line/low voltage compatibility makes it a go-to solution for a wide range of system configurations.

Specifications

• Model: W42AA-1
• Brand: Johnson Controls
• Humidity Range: 10 to 90% RH
• Differential: 4% RH
• Voltage: Line or Low Voltage
• Contact Type: SPDT (Single-Pole, Double-Throw)