Air Temperature Sensor Connections; Lennox Communicating Terminal Connections And Wiring Recommendations; Dual-Fuel Terminal Connections; Conventional Terminal Connections And Wiring Requirement - Lennox EIM Installation And Setup Manual

Air Temperature Sensor Connections

Refer to "Figure 1. Terminals and LEDs" on page 3 for various
terminal locations.
Table 4. Outdoor Air and Discharge Air Sensors
Label Function / Description
Show ambient temperatures (optional if weather feed is acceptable or
outdoor unit is a communicating unit; use X2658 Outdoor Sensor - 2
terminals).
Outdoor Air
NOTE: Wiring distance between the EIM and the outdoor temperature
Sensor
sensor can not exceed 150 feet (45 meters) when wired with
minimum 22AWG (Recommend) 18AWG dedicated two-
conductor thermostat cable.
Discharge Air Optional for diagnostics of indoor air; use 88K38 Discharge Air Sensor -
Sensor 2 terminals.
Lennox Communicating Terminal Connections and Wiring
Recommendations
Table 5. Communicating Terminals
Label Function / Description
R 24VAC communication power Input
i+ Communication high – data line
i- Communication low – data line
24VAC communication common
C
power Input
IMPORTANT
Use 18AWG unshielded thermostat cable (field-provided) for power
terminals (R and C) and all non-communicating terminals. Highly
recommend using 18 - 22AWG shielded thermostat cable for
communications terminals ( i+ and i-) which will help eliminate any noise
interference.
Thermostat Wiring
18AWG unshielded
18 - 22AWG shielded
(recommended)
18AWG unshielded

Dual-Fuel Terminal Connections

Table 6. Dual-Fuel Terminals
Label Description
Pre-coil discharge
DFTS air temperature (2
terminals)
W1-DEF Defrost signal input
Heat Pump Reversing
0 Valve (Powered for
cooling)
Heat Pump Reserving
Valve
B
(Powered for
heating)

Conventional Terminal Connections and Wiring Requirement

Table 7. Conventional Terminals
Label Description
18AWG unshielded thermostat cable (field-provided) for
all non-communicating connections
1st - stage heat output (1st stage gas heat output when configured as IFC
W1
and 1st stage electric heat output when configured as AHC.
2nd - stage heat output (2nd stage gas heat output when configured as
W2
IFC and 2nd stage electric heat output when configured as AHC.
3rd - stage heat output (3nd stage electric heat output when configured as
W3
AHC)
6
Function
The pre -coil discharge air sensor should be
installed downstream of the gas heat exchanger
and before the in door coil when a heat pump is
used and defrost tempering is required.
It must be placed in free airflow, where other
accessories (such as humidifiers, UV lights, etc.)
will not interfere with its accuracy. Wiring distance
between the EIM and the discharge air sensor
should not exceed 10 feet when using 18AWG
thermostat wire.
This input is used in systems with non-
communicating heat pumps for defrost indication.
The input provides a nominal load of 50 mA, 24
VAC.
In systems with communicating IFC, the EIM (HP)
O output is connected to a non-communicating
heat pump compatible with O signal for reversing
valve operation. A 24VAC signal is generated on
O for cooling operation, while the terminal is open
for heating operation.
In systems with communicating IFC, the EIM (HP)
B output is connected to a non-communicating
heat pump compatible with B signal for reversing
valve operation. A 24VAC signal is generated on
B for heat pump opera tion, while the terminal is
open for cooling operation.
Function