Trane CONTH01AAUTOA Installer's Manual

24V

RC

BYPASS

ODTH

POWER

STEP 1: Unpack the Humidifier Control Carton

Make sure all components are present (see Figure A):

A. Humidifier Control C. Manual Mode Label
B. Outdoor Temperature Sensor D. Manual Mode Resistor Case

ALL phases of this installation must comply with NATIONAL, STATE AND LOCAL CODES

IMPORTANT – This Document is customer property and is to remain with this unit. Please return to service information
pack upon completion of work.

THIS INFORMATION IS FOR USE BY INDIVIDUALS HAVING ADEQUATE BACKGROUNDS OF ELECTRICAL AND MECHANICAL EXPERIENCE. ANY ATTEMPT
TO REPAIR A CENTRAL AIR CONDITIONING PRODUCT OR ACCESSORY HUMIDIFIER OR HUMIDIFIER CONTROL MAY RESULT IN PERSONAL INJURY AND/OR
PROPERTY DAMAGE. THE MANUFACTURER OR SELLER CANNOT BE RESPONSIBLE FOR THE INTERPRETATION OF THIS INFORMATION, NOR CAN IT
ASSUME ANY LIABILITY IN CONNECTION WITH ITS USE.

These instructions do not cover all variations in systems or provide for every possible contingency. Should further information be desired or particular
problems arise which are not covered sufficiently by this manual, contact your local distributor or the manufacturer as listed on the humidifier nameplate.

Use the “OFF” setting to turn the
Humidifier Pad Change indicator OFF.

Use setting “A” for very
hard water conditions in
any location. Humidifier Pad
Change indicator LED light
will activate after 75 hours
of solenoid valve operation.

Use setting “B” for winters
in the South.

Humidifier Pad
Change indicator LED light
will activate after 300 hours
of solenoid valve operation.

Use setting “C” for winters in the Midwest
and Eastern United States. Humidifier Pad
Change indicator LED light will activate after
600 hours of solenoid valve operation.

Figure B

BYPASS/POWER
MODE SWITCH

HUMIDIFIER
PAD INDICATOR
SETTING

90-1010

Installer’s Guide

18-CH31D1-3

Automatic Humidifier Control

*CONTH01AAUTOA

*May be “A” or “T”

READ COMPLETE INSTALLATION INSTRUCTIONS AND TEMPLATE BEFORE STARTING.

WARNING:

HAZARDOUS VOLTAGE – DISCONNECT POWER BEFORE INSTALLING OR SERVICING

WARNING

CAUTION

A

D

HUMIDIFIER PAD
CHANGE INDICATOR

Figure A

C

B

90-1009

STEP 2: Disassemble the Humidifier Control

Remove door from the Humidifier 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). Make sure the switch is correctly set for
the type of humidifier being installed or damage to the Humidifier Control
could result (see Figure B).

STEP 4: Check the Change Humidifier Pad Indicator Setting

This setting controls the indicator light interval, reminding you to change your
Humidifier Pad. If your Control came with a humidifier, the Control is pre-set at
position “C”. 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 B). The Control
must be energized to reset the Humidifier Pad Indicator.

1. 120 volts may cause serious injury from electrical shock. Disconnect
electrical power to the furnace before starting installation.

2. Sharp edges may cause serious injury from cuts. Use care when

cutting plenum openings and handling ductwork. Use personal
protective equipment when installing or servicing HVAC equipment.

1. Do not set humidity higher than recommended. Property damage may

result.

2. Do not set humidity up to recommended levels if there is condensation

on the inside of windows of any unheated living space. Property
damage may result.

3. Do not mount Humidifier Control on supply plenum or duct. The Control

will not withstand supply temperatures.

4. When installing Humidifier Control on downflow furnaces, ensure

blower continues to run after a heat call is satisfied to eliminate high
temperatures from damaging the Humidifier Control.

5. Do not mount Humidifier Control downstream of the bypass outlet. The

Control will not operate correctly due to false humidity readings.

6. Set the Bypass/Power mode switch in the proper position, or damage

to the Humidifier Control could result (see Step 3).

THESE INSTALLATION INSTRUCTIONS ARE FOR THE AUTOMATIC HUMIDIFIER CONTROL ONLY!

For Humidifier installation, follow Humidifier Installation Instructions.

© 2008 Trane. All rights reserved. 18-CH31D1-3

DOOR

Note: The Control may installed in automatic or manual mode.

STEP 9: Route the Wire from Control to Sensor

Run a separate 18 ga. control 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 inch, and
insert the wires from the
Sensor into the terminals
labeled “ODT” on the
Humidifier Control. See
Figure F for location of
terminals.

Installing the Humidifier Control for Manual Operation

If it is not feasible to use the Outdoor Temperature Sensor, the
Humidifier Control can be operated in Manual Mode.

1. Connect the Manual Mode Resistor Case wires to the terminals
labeled “ODT” on the Humidifier 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.

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 E.

If it is not feasible to use the
Outdoor Temperature Sensor
in any of the ways described,
the Humidifier Control can be
installed for Manual Operation.
See box “Installing the
Humidifier Control for Manual
Operation” and Figure G for
details.

STEP 11: Determine Power Source for Humidifier Control

Determine where you will get 24 VAC to power the Humidifier Control
(see 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
Humidifier Control.

• 120 VAC: Wire to a 24 VAC transformer, which in turn connects to the “R”
and “C” terminals on the Humidifier Control.

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 Humidifier Control.

In either case, the voltage to the Humidifier Control must be between
22 VAC and 30 VAC. Run a separate 18 ga. wire from a 24-volt supply to the
humidifier control.

NOTES:

• The Humidifier 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 Power
Humidifiers; or 10.0 VA for Bypass Humidifiers.

• When power is connected for the first time, the red and green LEDs will
light momentarily.

STEP 12: Wiring

See Diagrams A-D for wiring options.

Figure G

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 D)

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 conflicts and warnings.

90-1013

Figure F

90-1012

Figure E

90-999

STEP 5: Determine Location for Humidifier Control

and Mount It

Humidifier Control must be mounted in the Return Duct. For proper operation,
the Humidifier Control must be at least 6 inches upstream of any of the
following:

• Humidifier

• Humidifier Bypass Ductwork (if applicable)

• Fresh Air Intake Ductwork (if applicable) (see Figure C)

After location for Control
is selected, use the
perforated Humidifier
Control template
(attached to these
instructions) to mark the
duct opening and cut it.
Use 4 sheet metal screws
(not provided) to mount
the Humidifier Control in
the duct opening and

make sure Humidifier
Control is sealed tightly
to duct.

Figure C

90-1137

NORTH, EAST
OR WEST SIDE
OF HOME

OUTDOOR

TEMPERATURE

SENSOR

SENSOR

BRACKET

SENSOR

ABOVE EXPECTED

SNOW LINE

OUTDOOR

TEMPERATURE SENSOR

LEADS

Figure D

90-998

CAUTION

Do not mount control on supply air plenum or duct. Failure to follow this
caution my cause property damage.

18-CH31D1-3

RETURN

DUCT

HUMIDIFIER

CONTROL

FRESH AIR

INTAKE

CONNECTION

6" MIN.

BYPASS

HUMIDIFIER

COIL

36" MAX.

OUTSIDE WALL

CENTER LINE

BYPASS

POWER

RC

ODTH

24V

BYPASS

POWER

R

C ODTH

24V