4
W43A Humidistat Product/Technical Bulletin
IMPORTANT: Do not remove the humidistat cover
during installation. The sensing
element must be carefully protected
against accidental damage. All wiring
and mounting can be completed
without removing the cover.
!
CAUTION:
Shock hazard.
Disconnect
power supply before wiring
connections are made to prevent
electrical shock or possible
damage to the equipment.
To mount the W43A Humidistat:
1. Select the proper mounting location (refer to the
Location Considerations
section) and install a
vertical or horizontal wall box 4 to 5 feet
(1.2 to 1.5 m) above the floor.
2. Run conduit or cable, as required by national
and/or local electric codes, from the wall box to the
equipment to be controlled. Leave approximately
6 in. (152 mm) of wire for connection to the
humidistat terminals.
3. Remove the humidistat mounting plate by
loosening the mounting plate locking screw (see
Figure 3), and lifting and removing the plate from
the base.
4. Pull wires through the mounting plate and fasten
the plate, grounding screw end up, to the wall box
with the screws provided.
5. Strip the wires and connect to the proper terminals
on the 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. Push the wires back flush
into the wall box.
8. Securely tighten the mounting plate locking screw.
O
ptional Horizontal Faceplate Installation
1. Mount and wire the humidistat according to the
steps outlined in the
Installation
section.
2. Pull the adjustment knob off the humidistat cover.
3. Peel off the backing of the horizontal faceplate.
4. Position the horizontal faceplate over the factory-
installed vertical faceplate. Be sure to position the
plate straight and even over the existing plate.
5. Firmly press the horizontal faceplate onto the
humidistat cover.
6. Replace the adjustment knob.
W
iring Diagrams
Relay
Exhaust
Fan
Range
Kitchen
Dining Area
or Hall
120 VAC
N
L
H C Humidistat
Manual
Fan
Switch
Figure 4: Typical Wiring Diagram of a W43A Used to
Reduce Excessive Humidity in a Well-Constructed
Building by Manual or Automatic Control
of Exhaust Fan
Dehumidifier
Humidistat
L
H
C
120
VAC
L
N
Figure 5: Dehumidification Control Wiring Diagram
