Manual Humidifier Control

The Aprilaire 4655 manual humidifier control is designed for professional HVAC installations requiring dependable humidity regulation in residential and light commercial systems. This control provides manual adjustment of relative humidity levels and is suitable for use with 24 VAC humidification systems. Engineered for straightforward installation and long-term reliability, it offers consistent operation with single-pole, single-throw (SPST) switching and a calibrated dial for precise system control.

Details

• Model: 4655
• Manufacturer: Aprilaire
• Product Type: Manual Humidistat
• Control Range: 15% to 50% Relative Humidity
• Differential: 8% RH
• Switch Type: SPST (Single-Pole, Single-Throw)
• Voltage Rating: 24 VAC
• Width: 4-1/2 inches
• Height: 2-3/4 inches
• Depth: 2-1/8 inches
• Mounting Type: Wall or return-duct mounted configuration
• Construction Features: Calibrated adjustment dial, durable housing, low-voltage terminals for secure wire connections
• Application: Manual humidity control for central HVAC humidification systems
• Compliance: UL recognized for low-voltage HVAC control use
• Part Number: 1892741

Summary

The Aprilaire 4655 manual humidistat provides contractors with a reliable, low-voltage control solution for managing humidity levels in HVAC systems. Featuring a 15–50% RH adjustment range, 8% differential, and SPST 24 VAC switch, it delivers precise manual control and dependable operation in residential and light commercial humidification applications.