4.9 Control Wiring (cont.)
control system requires continuous 18 AWG
thermostat wire. Do not use phone cord to
connect indoor and outdoor units. This will
damage the controls.
The communicating control system requires four
(4) control wires for unit operation:
• R 24 VAC
• C 24 VAC common
• Data wire E1 Communications
• Data wire E2 Communications
The communicating air handler or furnace is
equipped with a 24-volt, 40 or 50 VA transformer
for proper system operation. See the wiring
diagram below for low voltage wiring connections.
These wires need to be connected to each device
(Digital Control Center, indoor air handler or
furnace, and outdoor unit).
Once all devices are connected, apply the line
voltage to the indoor and outdoor units.
When all devices are powered, the Digital Control
Center should detect the indoor and outdoor units
within 45 seconds.
Once the system is powered and all components
are communicating with each other, the airflow
settings will be automatically configured in the air-
handler or furnace.
All adjustments for indoor airflow are made at
the Digital Control Center from this point. Items
that can be changed are airflow trim adjustment,
on-demand dehumidification, cooling and heating
airflow and electric heat airflow. The Digital Control
Center also has a wide range of fault and history
information. To access any of the control center
menus press the settings, status, or service icons
at the bottom of the touch screen. Refer to the
air handler or furnace installation manual and the
Digital Control Center installation manual for further
details on setting up the system and available
4.9.4 Conventional 24VAC
Thermostat Control Wiring
The 20 SEER heat pumps allow the installer to
use conventional 24 VAC control wiring and a
conventional thermostat for limited unit operation.
The system will operate as a single stage system
at nominal capacity.
method of unit installation and operation is by the
Communicating System which allows access to
the fault history of the system. This diagnostic
information is not available at the thermostat when
the unit is using a conventional thermostat.
Thermostat control wiring requires a minimum of
five (5) wires for proper unit operation:
R – 24 VAC
C – 24 VAC common
Y1 – Nominal capacity operation
B – Heat pump operation
W – Supplemental Heat During Defrost Cycle
The following figures show the typical control
wiring diagrams with 20 SEER heat pumps using
a conventional 24VAC thermostat. Cooling and
heating airflow levels will need to be adjusted
for homeowner comfort once the system is
operational. Use DIP switches on the air-handler or
furnace control board to adjust indoor air-flow.
WIRE COLOR CODE
BK – BLACK
GY – GRAY
BR – BROWN
O – ORANGE
BL – BLUE
PR – PURPLE
G – GREEN
R – RED
TYPICAL SINGLE-STAGE THERMOSTAT:
HEAT PUMP WITH AIR-HANDLER
USING A THERMOSTAT WITH DEHUMIDIFICATION
W – WHITE
Y – YELLOW