DH90 Dehumidifier • For HVAC Installer Only
The DH90 plugs into a common grounded 115VAC
outlet. The device draws 6.2 Amps under normal
operating conditions. If used in an area which
may become wet, a ground fault interrupter (GFI)
protected circuit is recommended.
ImPORTANT: Do not install the humidistat
where it may not accurately sense the relative
humidity such as near HVAC supply registers,
near exterior doors, on an outside wall, near a
window, or near a water source.
Refer to Section 6 for typical hookup diagrams.
Some of the control wires leaving the DH90 may
not be used with certain installations and should
be left unconnected with wire nuts taped onto the
stripped ends for safety.
4.3 Condensate (Water) Removal
The DH90 removes a large amount of moisture
from the air and the device must be connected to
a drain line that will carry away the excess water. A
trap in the drain line is recommended and may be
required by some local codes.
The drain line should be connected to the 3/4" male
pipe thread adaptor on the front of the DH90.
Care should be taken to install the drain line with
a continuous slope of 1" per 10' to assure proper
Figure 1: Ducting to isolated areas.
Fresh air intake
ImPORTANT: When connecting ventilation
duct, remove the label and 6" round
insulation plug from the ventilation duct
opening. If not using ventilation feature,
leave the insulation intact.
For the ideal installation, draw air from the central
part of the home and return it to the isolated areas
of the home like the bedrooms, den, utility room,
or family room. See Fig. 1. Alternative installation
option can be completed by drawing air directly
from the return ducting and distributing through
the supply air to the home.
4.4A Fresh Air / Supply Air
ImPORTANT: DO NOT draw air directly from
the kitchen, laundry, or isolated basement.
Air may be drawn from a basement that is open
to the home. All flexible ducting connected to the
DH90 should be UL listed.
A short piece of flexible ducting on all DH90 duct
connections is recommended to reduce noise
and vibration transmitted to rigid ductwork in the
structure. Ducting the DH90 as mentioned requires
consideration of the following points:
Duct Sizing: For total duct lengths up to
25', use a minimum 10" diameter round or
Ducting to isolated areas