Install Instructions

54
STEP 2: Disassemble the Humidifier Control
Remove the knob. Remove the cover by pulling at the bottom and
swinging it out and upward. See Figure B to become familiar
with the terminal positions. Figures K and L show complete
installation wiring diagrams for Aprilaire Humidifiers.
Figure B – Digital Humidifier Control 24V Terminals
90-1397B
HHGfW GODTBACR
OUTDOOR
TEMPERATURE
SENSOR
24 VAC FROM
HVAC EQUIPMENT
“R” AND “C”
COMMUNICATION
WITH APRILAIRE
8570 THERMOSTAT
HEAT SIGNAL
FROM HVAC
EQUIPMENT
FAN SIGNAL
FROM
THERMOSTAT
SOLENOID
CONTROL
OUTPUT
FAN SIGNAL
TO HVAC
EQUIPMENT
Reversing the R and C terminals on humidifier control
will cause improper operation.
Water Panel
Indicator
Settings
STEP 3: Set the Change Water Panel Indicator
This setting will control when the indicator light turns on,
reminding you to change your water panel. If your Control came
with a humidifier, the Control is pre-set for the humidifier. If the
installation site has a 3-month or shorter heating season or very
hard water, you may want to adjust the setting (see Figure C).
Set to “OFF” for Model
800 Series humidifiers or
to turn the Humidifier Pad
Change indicator to off.
Set to “A” for Model
400 Series humidifiers
in areas with very hard
water. The indicator
will light after 150
hours of operation.
Set to “B” for Model 400
Series humidifiers; and
Model 500 Series, 600
Series and 700 Series
humidifiers in areas with
very hard water. The
indicator will light after
300 hours of operation.
Set to “C” for Model 500 Series, 600 Series
and 700 Series humidifiers. The indicator will
light after 600 hours of operation.
Figure C
90-1202B