MODEL A77 – REMOTE OR EXTERNAL CONTROL AND WIRING
NOTE:
Use 18-22 AWG wire for control wiring�
The internal dehumidifier control can be used to control humidity, or a
remote Model A77 Control or other external control (see below) can be
wired to the dehumidifier�
Without an external control, the dehumidifier will turn on its blower for
three minutes every 15, 30 or 45 minutes depending on how often the
unit is set to sample the air� The dehumidifier can also be set to sample
the air continuously (see
AIR SAMPLING
on page 7)� The blower is
turned on to get a representative reading of the room relative humidity�
A shorter sampling period reduces the duration of any humidity spikes
that might occur when neither the air conditioning nor the dehumidifier
are running� To reduce energy consumption the sampling time can be
set to a longer period�
Installing an A77 or other control eliminates the need to run the
dehumidifier blower for sampling as the control is constantly measuring
the humidity close to the canopy� When the humidity level rises above
the setting, the dehumidifier is turned on�
To install the Model A77 control:
1.
Turn off power to the dehumidifier using the ON/OFF switch�
2.
Run a 4-wire thermostat cable (use 18–22 AWG wire) from the Model A77 to the control of the dehumidifier�
3.
Trim about 1/4" of insulation from the end of the wires on each end� Insert the wire into the terminals as shown in
FIGURE 4
and tighten to secure�
4.
Restore dehumidifier power� There is a delay of three minutes after restoring power before the dehumidifier will respond to the control�
5.
Go to
REMOTE CONTROL
on page 6 to configure the dehumidifier control to respond to an A77 control�
The Model A77 will measure the relative humidity and turn the dehumidifier on and off to control the humidity level to the desired setting� The
humidity setting can be adjusted from the control while the display allows easy access and monitoring of the humidity level in the space� It is
recommended that the Model A77 be mounted at/near canopy height�
Press the ON button on the Model A77 to turn on the control� The UP/DOWN arrow buttons are used to set the desired humidity setting� At all other
times, the Model A77 will display the measured humidity level� Reference the Model A77 Installation & Operating Instructions for set-up�
ALTERNATE EXTERNAL CONTROLS
A Model 8840 thermostat can be used to control the HVAC equipment, and for dehumidifier control in place of the Model A77� The Model 8840
thermostat has Wi-Fi capability so the conditions in the room can be monitored at any time from any location� Additionally, up to four remote sensors
can be mounted near the canopy and connected to a single thermostat� The four humidity measurements can be averaged and the thermostat will
turn on the dehumidifier based on the averaged value�
Reference the 8840 Installation Instructions and Owner’s Manual for wiring, set-up and operating details�
+ - A B
ODT
Sensor
Remote
Gh
Rf
Cf
Gs
Y
W
HV
AC E
QUIP
.
DH
DH
R/+
C/-
B
A
MODEL A77 CONTROL
90-1860
FIGURE 4
– MODEL A77 REMOTE CONTROL WIRING
5
