Model 76 - External Control Or Crawl Space/Sealed Attic Control And Wiring - Aprilaire 1870 Installation Instructions Manual

MODEL 76 – EXTERNAL CONTROL OR CRAWL SPACE/SEALED ATTIC
CONTROL AND WIRING
NOTE: Use 18-22 AWG wire for control wiring .
EXTERNAL CONTROL
Used as an external control, the Model 76 is
mounted in the space that is to be dehumidified .
When the dehumidifier is powered, the display on
the dehumidifier control will show "EXTERNAL"
to indicate that an external control is being used .
External controls are recommended when the
dehumidifier is installed in an attic and is ducted
to the HVAC system .
The Model 76 uses a normally open (NO), dry
contact (i .e . not a triac or other semiconductor)
relay to complete the circuit between the DH
terminals of the dehumidifier control . If using
other controls such as a thermostat with
dehumidification outputs, ensure the output is a
dry contact type and set the NO/NC switch on the
dehumidifier control (see Figure 17) to correspond
with the control being used . The Aprilaire Model
8620 Thermostat or Model 8910 Home Comfort
Control are recommended alternate controls and
both use normally open contacts .
If an external control is used in a zoned
application, it must be located in the Primary
Zone (refer to TWO ZONE – PRIMARY AND
SECONDARY on page 18 for details) .
CRAWL SPACE/SEALED ATTIC CONTROL
Used as crawl space or sealed attic control
(or remote control), the Model 76 is mounted
in the living space while the dehumidifier is
located in the area to be dehumidified . When
the dehumidifier is powered, the display on the
dehumidifier control will show "REMOTE" to
indicate that a remote control is being used . The
RH shown on the Model 76 is the RH measured
at the dehumidifier .
Remote control is typically used for crawl
space or sealed attic applications, but is also
recommended when the dehumidifier and the
space being dehumidified are inconvenient or
difficult for the homeowner to access . Examples
of this type of application include basements that
may be inconvenient to access or storage areas .
FIGURE 17 – Model 76 External Control Wiring
NO/NC SWITCH
+ - A B
Remote
NC NO
FIGURE 18 – Model 76 Crawl Space/ Sealed Attic (Remote) Wiring
+ - A B
Remote
ODT VENT DEH
Sensor Dampers
MODEL 76 CONTROL
ODT
Sensor
MODEL 76 CONTROL
A
B
C/-
R/+
DH
DH
90-1862
A
B
C/-
R/+
DH
DH
90-1860
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