Terminals And Wiring Specifications - Lennox iComfort E30 Installation And Setup Manual

Terminals and Wiring Specifications

The following is the wiring specification requirements for installation of this system.
• Maximum total length of all connections combined is 1500 feet (457 meters).
• Maximum length between components is 300 feet (90 meters).
Terminal
Description
Designation
Accessory 1 and
ACC1
2 (typically can be
used for 1 or 2 speed
ventilators and fresh
ACC2
air damper)
+ 12VDC output
-
12VDC return
Communications
A
bus A
Communications
B
bus B
IMPORTANT
Use 1-pair, 18AWG unshielded thermostat cable (field-provided) for power
terminals (R, C, 12+ AND 12-). Highly recommend using 1-pair 22AWG
shielded thermostat cable for communications terminals ( A and B) which will
help eliminate any noise interference.
Conventional Equipment Terminal Connections
Table 6. Conventional Terminals (24VAC)
Label Description
First-stage heat output (first-stage gas heat output when configured as furnace
W1
(IFC) and first-stage electric heat output when configured as air handler (AHC).
Second-stage heat output (second-stage gas heat output when configured as IFC
W2
and second-stage electric heat output when configured as AHC.
Third-stage heat output (third-stage electric heat output when configured as air
W3
handler)
Indoor blower control (continuous fan) (monitoring only). G input may be connected
G to IAQ devices such as humidifier, Lennox Ventilation Control System and Heat or
Energy Recovery Ventilators to turn the indoor blower on and off.
Table 5. Terminal Designations and Wiring Recommendations
Thermostat
Typical Wiring
Wiring
18AWG unshielded
18AWG unshielded
18 - 22AWG shielded
(recommended)
Function
Smart Hub
COMMBUS
ACC1 ACC2 +
-
A B
unshielded
18 or 22AWG
Table 6. Conventional Terminals (24VAC)
Label Description
Y2 Second-stage compressor output.
Y1 First-stage compressor output.
24VAC dehumidification signal output. The DS terminal is powered when there is
DS
not a dehumidification call.
Class II, 24VAC
C
transformer common
Class II. 24VAC
R
transformer power
H 24VAC humidifier signal output.
Heat pump reversing
O
valve (24VAC = cool)
Heat pump reversing
B
valve (24 VAC = heat)
6
HD Display
Subbase
+12V A B -12V
18AWG
shielded
Function
Both R and C terminals are used to receive power from
the indoor unit and capable of provid ing the power to the
Smart hub and all the associated loads. The R power
input uses a 3A fuse (Lennox part number 25J49.
Used as reversing valve output for heat pumps. The E30
uses a single-pole dual throw relay to generate O and
B signals. Normally the O output is open and B output
at 24VAC during heating calls. During cooling calls O is
24VAC and B open. With relay de- energized 24VAC is
present on O terminal.
When power off/ or control reset, 24VAC power shall not
be present on the O terminal.