MODEL A77 – REMOTE CONTROL AND WIRING
NOTE: Use 18-22 AWG wire for control wiring.
Humidity can be controlled using the internal dehumidifier control, a
Model A77 control or a different external control like a thermostat.
Installing an external 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 and use the Model A77 control, complete ALL steps:
1. Unplug the dehumidifier or turn off power to the circuit at the
breaker or fuse.
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 10 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. Set up the dehumidifier to ENABLE REMOTE control as shown on page 9.
6. See USING THE MODEL A77 OR EXTERNAL CONTROL on page 9 for start up instructions.
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. Shield the Model A77 from direct exposure to HPS or LPS lighting.
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 and Operating Instructions for set-up.
ALTERNATE EXTERNAL CONTROLS
Alternatively, use any other humidity control system as long as it
has a dry contact, normally open output dedicated to controlling the
dehumidifier.
When using an external control, set up the dehumidifier to ENABLE
EXTERNAL control as shown on page 9. Reference the installation
literature provided with the alternative control for wiring, set-up and
operating details.
+ - A B ODT
SensorRemote
Gh Rf Cf Gs YW
HVAC EQUIP.
DH
DH
R/+
C/-
B
A
MODEL A77 CONTROL
FLOAT
DH DH
SWITCH
EXTERNAL
90-1860
90-2542
FIGURE 10 – MODEL A77 REMOTE CONTROL WIRING
FIGURE 11 – ALTERNATE EXTERNAL CONTROL WIRING
8