Aprilaire 56 Setup guide

SAFETY AND INSTALLATION INSTRUCTIONS
Model 56
Automatic Humidier ControlHumidier
WARNING
• ATTENTION INSTALLER: Read this manual before installing.
Improper installation or maintenance may cause property
damage or injury. It is recommended that installation, service,
and maintenance be performed by a trained service technician.
This product must be installed in compliance with all local, state,
and federal codes.
• ELECTRIC SHOCK HAZARD: 120 volts may cause serious injury from
electric shock. Disconnect electrical power to the HVAC system
and humidier before starting installation or servicing. Leave
power disconnected until installation/service is completed.
CAUTION
SHARP EDGES MAY CAUSE INJURY FROM CUTS. Use care when
cutting plenum openings and handling ductwork. Always wear
glasses/goggles and gloves when installing the unit.
NOTICE
CONDENSATION DAMAGE OR MOLD CAN OCCUR.
• Do not set the humidier control higher than recommended.
• Lower the humidity setting on the humidier control if there is
excess condensation on the inside of any windows in unheated
living spaces.
CONTROLLER DAMAGE OR MALFUNCTION MAY OCCUR IF
INSTALLATION INSTRUCTIONS ARE NOT FOLLOWED.
• Install the humidier control on return plenum only.
• Install the humidier control upstream of the bypass outlet.
• Do not install the humidier control facing downward.
• When installing the humidier control on the return duct of a
downow furnace, ensure the blower continues to run after
a heat call is satised to eliminate high temperatures from
damaging the humidier control.
• Do not use solvents or cleaners on or near the display and circuit
board. Chemicals can damage components.
• Do not apply 120 VAC to the humidistat. The humidistat is
powered by 24 VAC. Disconnect power to the humidistat prior to
separating humidistat from its base.
THESE INSTALLATION INSTRUCTIONS ARE FOR THE APRILAIRE® AUTOMATIC HUMIDIFIER CONTROL ONLY.
FOR APRILAIRE® HUMIDIFIER INSTALLATION, FOLLOW APRILAIRE HUMIDIFIER INSTALLATION INSTRUCTIONS.
WATER PANEL CHANGE INDICATOR
DOOR
CD
B
A
90-1009
FIGURE 1
STEP 2: DISASSEMBLE THE HUMIDIFIER CONTROL
Remove door from the Humidier Control by pulling the bottom of the
door straight out.
STEP 3: CHECK THE MODE SWITCH
With the door removed, notice the switch labeled BYPASS and POWER
(partially covered by the enclosure). Use the following guide to
determine the correct setting for your humidier model.
POWER SETTING: Models 110, 112, 445, 448, 760, 700 (almond-colored), 768,
800 (steam humidier)
BYPASS SETTING: Models 220, 224, 400, 440, 500, 550, 558, 560, 568, 600,
700 (gray-colored)
Product Info &
Digital Manual
STEP 1: UNPACK THE HUMIDIFIER CONTROL CARTON
Make sure all components are present (see FIGURE 1).
A. Humidier Control
B. Outdoor Temperature Sensor
C. Manual Mode Label
D. Manual Mode Resistor Case

STEP 9: ROUTE THE WIRE FROM CONTROL TO SENSOR
Run wire to the outdoor temperature sensor. Sensor is not affected
by lead length. In either case, do not run outdoor temperature sensor
alongside wires carrying high voltage (120 VAC or higher). Secure the
sensor bracket with a #8 galvanized screw.
STEP 10: ATTACH SENSOR WIRE TO HUMIDIFIER CONTROL
Strip wire 1/4”, and insert the wires from the Sensor into the terminals labeled
ODT on the Humidier Control. See FIGURE 7 for location of terminals.
3 FEET
MAX.
CENTER LINE
OUTSIDE WALL
WIRING
TERMINALS
BYPASS
POWER
R
24V
C ODTH
90-999
90-1012
FIGURE 5
FIGURE 7
If it is not feasible to use the Outdoor Temperature Sensor, the
Humidier Control can be operated in Manual Mode.
1. Connect the Manual Mode Resistor Case wires to the terminals
labeled ODT on the Humidier Control.
2. Snap the Manual Mode Resistor Case into the slot provided so
that Resistor Case sticks out from the bottom edge of the base.
3. Remove the control knob
and apply the Manual Mode
label to the cover, aligning
the sticker and knob holes.
Re-install the knob.
FIGURE 6: INSTALLING THE HUMIDIFIER CONTROL
FOR MANUAL OPERATION
R
24V
BYPASS
C ODTH
POWER
90-1013
STEP 5: DETERMINE LOCATION FOR HUMIDIFIER CONTROL AND MOUNT IT
The Humidier Control
must be mounted in the
return duct. For proper
operation, the Humidier
Control must be at least
6 inches upstream of any
of the following:
• Humidier
• Humidier Bypass
Ductwork (if applicable)
• Fresh Air Intake
Ductwork (if applicable)
(see FIGURE 3)
After location for Control is selected, use the perforated Humidier
Control template (attached to these instructions) to mark the duct
opening and cut it. Use 4 sheet metal screws (not provided) to mount
the Humidier Control in the duct opening and make sure Humidier
Control is sealed tightly to duct.
STEP 6: DETERMINE LOCATION FOR OUTDOOR TEMPERATURE SENSOR
The location of the Outdoor Temperature Sensor must meet these three
requirements:
1. Must be mounted
on North, East
or West side of
house out of direct
sunlight.
2. Must be at least
3 feet from all
exhaust vents.
3. Must be above
expected snow
line (see FIGURE 4).
Incorrect humidity levels will result if these requirements are not met.
STEP 7: LOCATE EXISTING ACCESS HOLE TO OUTSIDE
A convenient way to get the sensor wire outside is to make use of
unused wires running to the A/C condensing unit (if applicable). Other
ways are to use existing holes for cable TV lines, telephone lines, A/C
lines, etc. Read all equipment instructions beforehand for possible
conicts and warnings.
6” MIN.
RETURN
DUCT
HUMIDIFIER
CONTROL
FRESH AIR
INTAKE
COIL
HUMIDIFIER
BYPASS
CONNECTION
FIGURE 3
90-1137
STEP 8: ALTERNATE LOCATION FOR OUTDOOR TEMPERATURE SENSOR
The Sensor can also be mounted in the center of either:
• 2 inch PVC fresh air intake pipe for the furnace
OR
• 6 inch fresh air intake duct. Mount the sensor with a #8 galvanized screw.
In both cases, the Sensor must be no more than 3 feet from the outside
wall. See FIGURE 5.
If it is not feasible to use the Outdoor Temperature Sensor in any of
the ways described, the Humidier Control can be installed for Manual
operation. See FIGURE 6 for details.
ABOVE EXPECTED
SNOW LINE
OUTDOOR
TEMPERATURE
SENSOR
LEADS
NORTH, EAST
OR WEST SIDE
OF HOME
SENSOR
BRACKET
SENSOR
OUTDOOR
TEMPERATURE
SENSOR
90-998
FIGURE 4
STEP 4: CHECK THE CHANGE WATER PANEL® INDICATOR SETTING
This setting will control when the indicator light turns on, reminding you to
change your water panel. If your Control came with a humidier, the Control
is pre-set. 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 2).
The Control must be energized to reset the Water Panel® Indicator.
BYPASS
POWER
Use the OFF setting to turn the Water
Panel Change indicator OFF.
Use setting
A for Model 400
humidifiers. The indicator will
light after 75 hours of inlet valve
operation, which corresponds to
approximately 300 hours of
humidifier operation.
Use setting
B for Model
600 and 700 humidifiers
when the heating season
is 3 months or less, or if hard
water is used. The indicator
will light after 300 hours of
humidfier operation.
Use setting
C for Model 600 and 700
humidifiers when the heating season is
longer than 3 months. The indicator will
light after 600 hours of humidfier operation.
MODE
SWITCH
WATER PANEL
INDICATOR SETTING
R
24V
C ODTH
90-1010
FIGURE 2

STEP 11: DETERMINE POWER SOURCE FOR HUMIDIFIER CONTROL
Determine where you will get 24 VAC to power the Humidier Control
based on the 2 options below.
OPTION 1: FURNACES WITH ACCESSORY TERMINALS
If the accessory terminals provide:
• 24 VAC: Wire these directly to the R and C terminals on the Humidier
Control.
• 120 VAC: Wire to a 24 VAC transformer, which in turn connects to the
R and C terminals on the Humidier Control.
In either case, the voltage to the Humidier Control must be between
22 VAC and 30 VAC.
OPTION 2: EXTERNAL 24 VAC TRANSFORMER
Wire into a power source other than the furnace blower circuit. The
transformer can be powered off the 120 VAC line at the junction box
before it enters the furnace. The 24 volt side of the transformer is
connected to the R and C terminals on the Humidier Control.
NOTES
• The Humidier Control will operate properly with either a switched or
continuous power source.
• Whether using Accessory Terminals or an External Transformer, the
minimum VA required is; 2.0 VA for humidiers using the Power setting
[Models 110, 112, 445, 448, 760, 700 (almond-colored), 768, 800 (steam
humidier)]; or 10.0 VA for humidiers using the Bypass setting [Models
220, 224, 400, 440, 500, 550, 558, 560, 568, 600, 700 (gray-colored)].
• When power is connected for the rst time, the red and green LEDs will
light momentarily.
STEP 12: HUMIDIFIER WIRING
Strip the wires used for all the Humidier Control terminal connections 1/4”.
• If Furnace Accessory Terminals are used, wire the humidier
solenoid valve in series with the H terminals on the Humidier Control
without using a Model 50 Relay. See furnace manual for operation of
accessory terminals (FIGURE 8).
• If an External Transformer is used, a Model 50 Current Sensing Relay
must be connected to the solenoid valve and the H terminals on the
Humidier Control to allow the humidier to operate only when the
blower is on (FIGURE 9). Wire the Model 50 Relay into the H circuit only.
Bypass and Power units are wired to the AHC in the same fashion.
NOTE: This control does not support intelligent communication with
other products.
BYPASS
POWER
R
24V
C ODTH
FURNACE
ACCESSORY
TERMINALS
(10 VA MINIMUM)
BYPASS
POWER
R
24V
C ODTH
H
L
C
TRANSFORMER
(10 VA MINIMUM)
FURNACE BLOWER
FIGURE 8: FURNACE ACCESSORY TERMINAL
FIGURE 9: CONSTANT POWER WITH EXTERNAL TRANSFORMER
CAUTION
SHARP EDGES MAY CAUSE INJURY FROM CUTS. Use care when cutting plenum
openings and handling ductwork. Always wear glasses/goggles and gloves
when installing the unit.
NOTICE
• Install the humidier control on return plenum only.
• Install the humidier control upstream of the bypass outlet.
• When installing the humidier control on the return duct of a downow
furnace, ensure the blower continues to run after a heat call is satised to
eliminate high temperatures from damaging the humidier control.
SYSTEM CHECKOUT
1. For system Test/Reset, be sure that 24 VAC is applied to the R and C
terminals of Humidier Control.
2. Snap the door back onto the Humidier Control Base.
3. Activate furnace blower and be sure thermostat is calling for heat.
4. Rotate the control knob of Humidier Control clockwise to the
TEST/RESET position. When the knob is set in the TEST/RESET position,
the green Change Water Panel light will blink. Make sure the knob
is not left in the TEST/RESET position when the installation is done.
Rotating knob to TEST position resets the water panel change timer
to zero. The Control must be energized to reset the Water Panel
indicator.
5. If all is set up properly, you should be able to hear the solenoid valve
click open. In TEST/RESET mode, the AprilAire Humidier will operate
for 1 minute.
6. If the humidier does not activate with the Humidier Control in the
TEST/RESET position, refer to the troubleshooting guide.
7. Setting the Humidier Control:
• If home is occupied, set Humidier Control to NORMAL (for Manual
operation, set to 35%).
• If home is vacant, set Humidier Control to OFF.
8. Inform homeowner to refer to the AprilAire Owner’s Manual for the
initial adjustment period.
9. Make sure the red diagnostic light is not lit. If the red diagnostic light
is lit, re-check your wiring.
CUT OUT TEMPLATE

TROUBLESHOOTING GUIDE
Applies to both Automatic and Manual operation unless indicated otherwise.
TABLE 1: MODEL 56 TROUBLESHOOTING GUIDE
HUMIDIFIER OPERATES CONSTANTLY
• If the humidity level in the home is less than the knob setting, the
Humidier Control will operate the Humidier until the humidity level is
higher than the knob setting.
• In the TEST mode, verify unit will operate for approximately one minute.
• Check the resistance of the Outdoor Temperature Sensor as instructed
above.
• Make sure the Outdoor Temperature Sensor is mounted completely
outside the house on the North, East, or West side of the house and out
of direct sunlight (automatic mode only).
• Rotate the Humidier Control knob counterclockwise to the OFF position,
and observe whether the humidier turns off. If the humidier still
operates in the OFF position, perform the following:
1. Check summary wiring diagram for correct Humidier Control
Installation.
2. Remove wires from Humidier Control’s H terminals. If Humidier
continues to operate, replace solenoid valve.
HUMIDIFIER OR HUMIDIFIER CONTROL “CHATTERS” OR CLICKS ON AND OFF
RAPIDLY
• Check for steady 22 VAC to 30 VAC with voltmeter.
• Make sure Outdoor Temperature Sensor wiring is not run alongside wires
carrying high voltage (120 VAC or higher) (automatic mode only).
RED DIAGNOSTIC LIGHT IS ON
• Check that the wiring is correct.
• Measure the resistance of the Outdoor Temperature Sensor by removing
the leads from the terminal and measuring the resistance across the
wires with an ohmmeter. Conrm the reading with the temperature in
TABLE 2. (For Manual operation, verify that the resistance across the leads
of the Manual Mode Resistor Case is between 44,000 and 48,000 ohms).
RED DIAGNOSTIC LIGHT
BYPASS
POWER
R
24V
C ODTH
90-1012
B2202617D • 10005402 • 08.23
© 2023 AprilAire | aprilairepartners.com | 800.334.6011
AprilAire reserves the right to change specications without notice.
HUMIDIFIER CONTROL TEMPLATE
4-3/4” x 3”
1. Cut out template along edges.
2. Place template on the return plenum upstream of (before)
the humidier connection.
3. Trace outside edges of template.
4. Remove template and accurately cut plenum opening.
5. Using 4 sheet metal screws, install Humidier Control in
plenum opening.
TABLE 2
Outdoor Temperature (°F) -30 -20 -10 010 20 30 40 50 60 70 80 90 100
Resistance (kΩ) 230.6 163.8 117.6 85.4 62.6 46.3 34.6 26.1 19.9 15.3 11.9 9.4 7.4 5.9
TABLE 1: MODEL 56 TROUBLESHOOTING GUIDE
“CHANGE WATER PANEL” INDICATOR IS LIT
• Call your installer to have your water panel changed, or visit your
installer to purchase a new AprilAire water panel. Follow the instructions
on the water panel box.
HUMIDIFIER DOES NOT OPERATE IN “TEST” MODE
• Make sure furnace blower is operating and thermostat is calling for
heat.
• Make sure the Outdoor Temperature Sensor is connected to the ODT
terminals of the control. (For Manual operation, make sure Manual Mode
Resistor Case is in place.)
• Check main wiring diagram for correct Humidier Control installation.
• If connected to a Model 400 Humidier, make sure both oats in the
bottom of the scale control insert are in the down position. If necessary,
dump out water to lower oats.
• Check voltage at Humidier Control R and C terminals. Voltage should
be 22 VAC minimum to 30 VAC maximum.
• Check Model 50 Current Sensing Relay (if used) for correct installation
(see Model 50 instructions). Do not use Model 50 Relay in transformer
circuit or R and C circuit of Humidier Control. Model 50 relay is to be
used in the H circuit only.
• In TEST mode, humidier will operate for 1 minute only. DO NOT LEAVE IN
TEST MODE AS HUMIDIFIER WILL NOT OPERATE.
• Make sure saddle valve is open.
HUMIDIFIER OPERATES ONLY IN “TEST” MODE
• If outdoor temperature is greater than 60°F or less than -30°F, the
Humidier Control will only operate in the TEST mode (for one minute).
• If the humidity level in the home is higher than the knob setting, the
Humidier Control will not operate the Humidier.
• Check the resistance of the sensor by removing the leads of the
Outdoor Temperature Sensor from the terminals and measuring the
resistance across the wires with an ohmmeter. Compare reading to
outdoor temperature in TABLE 2 . (For Manual operation, verify that
resistance across the leads of Manual Mode Resistor Case is between
44,000 and 48,000 ohms).
• Make sure the Outdoor Temperature Sensor is mounted completely
outside the house on the North, East, or West side of the house and out
of direct sunlight (automatic mode only).
• If Outdoor Temperature Sensor is mounted in fresh air intake duct,
make sure the probe is no more than 36 inches from the outside wall
(automatic mode only).
• Make sure the Outdoor Temperature Sensor is located at least 3 feet
away from all exhaust vents (automatic mode only).
CUT OUT TEMPLATE