Master Catalog 125
Humidity Controls Section
W
Product/Technical Bulletin W43A
Issue Date 0918
© 2018 Johnson Controls
1
Part No. 24-8466-1, Rev. A
Code No. LIT-125715
W43A Humidistat
The W43A Humidistat controls humidifying and/or
dehumidifying equipment. Typical uses include the
control of humidity by ventilation, air conditioning,
humidifiers, and dehumidifiers in residential,
commercial, and industrial installations.
The W43A has Single-Pole/Double-Throw (SPDT)
snap-acting contacts rated to switch 1/4 hp motors. It
has a wide setpoint range of 0 to 70% Relative
Humidity (RH), as well as “off” dial positions for
humidification and dehumidification. The differential of
the W43A is fixed at approximately 6% RH.
Figure 1: W43A Humidistat with Vertical Faceplate
Features and Benefits
Human Hair Sensing Element
Provides stable, accurate measurement
1/4 hp (6A) Rated Contacts
Permits direct operation of many fans in
commercial applications
High/Low Adjustable Knob
Range Stops
Allows adjustments within a desired range
Enclosed Pennswitch
Provides dust protection for contacts
Mounting Plate
Allows easy mounting and wiring without
removing the cover
