Aprilaire 400 Series - Installation Steps; Component Preparation; Plenum Opening and Humidifier Mounting; Bypass Duct and Water Panel Installation

Insert feed tube into distribution tray. Turn damper handle to WINTER when in use.
6”
TEMPLATE
LEVEL
DO NOT
POSITION
OPENING IN
FRONT OF
COOLING
COILS
MINIMIZE
DISTANCE
6”
FLOOR
DRAIN OR
CONDENSATE
PUMP
DRAIN SPUD
HOSE CLAMP
OVERFLOW
TUBE
Tighten water line by double wrenching.
Locate manual or digital humidier control on the
return 6” above the humidier or bypass duct. Completed installation.Location of manual humidier control in living space.
Secure base with screws.
Press tabs
to remove cover.
Pull feed tube out of distribution
tray, and remove Water Panel
evaporative assembly. Cut opening using this template.
OVERFLOW
TUBE:
• Ensure
downward
slope and
no kinks.
• Do not over-
tighten hose
clamp onto
drain spud.
• Do not use
solvent
adhesive on
drain spud.
INSTALLATION INSTRUCTIONS
COMMON
HI
LO
FURNACE
BLOWER MOTOR
MODEL 50 CURRENT
SENSING RELAY (IF REQUIRED)
24 VAC FURNACE
ACCESSORY
TERMINALS OR
TRANSFORMER
(10VA MINIMUM)
SHUT-OFF
(SADDLE VALVE)
WATER SUPPLY
CONNECT OVERFLOW
TUBE HERE
YELLOW
WIRES
WHITE
WIRES
WHITE
WIRES
G
Y
W
C
R
R
C
W
Y
G
OUTPUTSINPUTSPOWER
GWCR HHODT Gf
YELLOW
WIRES
THERMOSTAT OR
ZONE PANEL
EQUIPMENT TERMINALS
110 VAC
FURNACE
OUTDOOR
TEMPERATURE
SENSOR FOR
AUTOMATIC MODE
NORTH, EAST
OR WEST SIDE
OF HOME
ABOVE EXPECTED
SNOW LINE
CONTINUOUSLY POWERED
24 VAC TRANSFORMER
PROVIDED WITH HUMIDIFIER
WATER
SUPPLY
CONNECT
OVERFLOW
TUBE HERE
ADHC TERMINAL STRIP
INSTALLATION
CHECKLIST
Saddle valve is
fully open.
All plumbing
connections
are watertight.
Humidier
functions
properly.
Bypass
damper is in
proper position.
Owner’s
manual has
been given to
homeowner.
MODEL 400 DIGITAL HUMIDIFIER CONTROL WIRING MODEL 400M MANUAL CONTROL WIRING
90-1513
90-1399
TEMPLATE MUST BE LEVEL
B2205115H • 10008973 • 10.23
© 2023 AprilAire | aprilairepartners.com | 800.334.6011
AprilAire reserves the right to change specications without notice.
IMPORTANT: Use 120 VAC power source
other than furnace blower circuit.
However, the transformer can be
powered off the hot 120 VAC line before
it enters the furnace. Do not wire
transformer into furnace blower circuit.
IMPORTANT: When Model 50 current sensing relay is used, wire
Model 50 current sensing relay into 24 VAC humidier control
circuit only! Do not install in transformer primary circuit.
NOTE: Control will display software revision level, e.g., r3,
when the one minute test cycle has completed. Refer to the
control installation manual for system checkout instructions.
6
5
8a
8b
9
7
1
4
2
3
90-2248
90-2248
90-1666
90-2248 90-1165
90-2248
90-2248
90-1068 90-2248
90-1069