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Master Catalog

125

Humidity Controls Section

W

Product/Technical Bulletin

W43A

Issue Date

1095

© 1995 Johnson Controls, Inc.

1

Part No. 24-8466-1, Rev. —
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

Summary of Contents for W43A

Page 1: ...ng 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...

Page 2: ...uit is open and the C to L terminal controls the humidification equipment At any given setpoint the C to L circuit closes on a decrease in relative humidity and the C to H circuit closes on an increase in relative humidity The usual setting in winter is 30 to 40 RH Lower settings may be necessary in extremely cold weather to prevent condensation on windows doors etc The same setting should be used...

Page 3: ...1 27 32 0 25 6 1 59 40 4 71 120 2 34 59 3 22 82 1 20 30 1 41 36 0 80 20 Figure 2 W43A Dimensions in mm Mounting and Wiring Optional Concealed Adjustment Faceplate Adjustment Knob Mounting Plate Locking Screw Vertical Faceplate Mounting Plate Wall Box Cover Locking Screw Grounding Screw Figure 3 W43A Humidistat ...

Page 4: ... back of the humidistat See Wiring Diagrams section Note Use the terminal screws furnished 8 32 x 1 4 in binder head Substitution of other screws may cause problems in making proper connections 6 Connect the grounding provision of the humidistat to the branch circuit ground 7 Hook the two slots in the humidistat base over the projections on the mounting plate and swing the humidistat into place Pu...

Page 5: ...ures to set the high and low range stops High Range Stop 1 Set the adjustment knob to the maximum desired RH setting 2 Pull the adjustment knob off the humidistat cover 3 Loosen the bottom cover screw and remove the humidistat cover CAUTION Equipment damage hazard Avoid contact with human hair sensing element Contact with hair element can affect control accuracy and or product life 4 While holding...

Page 6: ...e bottom cover screw and remove the humidistat cover CAUTION Equipment damage hazard Avoid contact with human hair sensing element Contact with hair element can affect control accuracy and or product life 4 While holding the dial firmly in place keeping the setting in line with the calibrating mark depress the tab A and rotate it counterclockwise until it is against the stop C Depress the tab B an...

Page 7: ...ontrols Catalog Concealed Adjustment Faceplates Concealed adjustment faceplates are available on factory order at no extra cost For field changeover use the concealed faceplate kit and install directly over the faceplate on the cover See Table 3 for ordering information Table 3 Optional Accessories Item Product Code Number Concealed Adjustment Faceplate Vertical Mounting PLT333 12R Concealed Adjus...

Page 8: ...odized Aluminum Mounting Vertical or Horizontal 2 x 4 in 51 x 102 mm Wall Box Wiring Terminals Large 8 32 x 1 4 in Binder Head Screws Minimum Ambient Temperature 40 4 4 C Maximum Ambient Temperature 100 F 38 C Agency Listings UL Guide No XAPX File E6688 CSA Class No 4813 02 File LR948 Dimensions H x W x D 4 71 x 2 96 x 2 94 in 120 x 75 x 75 mm Shipping Weight 0 9 lb 0 4 kg The performance specific...

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