Lennox 10T50 Assembly instructions

507240-03
1/2018
Supersedes 6/2017
iComfort®Equipment
Interface Module
Installation and Setup
Guide
(10T50)

2
Shipping and Packing List.................................................................2
Application and Requirements..........................................................2
Indoor Transformer Requirements................................................... 2
Equipment ....................................................................................... 2
Installation...........................................................................................5
Conguration Setup...........................................................................5
EIM, 24VAC Furnace and iComfort Heat Pump .............................. 5
EIM, iComfort Furnace and 24VAC Heat Pump .............................. 5
Unit Type Jumpers........................................................................... 6
Heat Stage Jumper Positions .......................................................... 6
Air Temperature Sensor Connections.............................................. 6
iComfort Terminal Connections ....................................................... 6
Heat Stage Jumpers........................................................................ 7
Dual-Fuel Terminal Connections ..................................................... 7
Conventional Terminal Connections................................................ 8
LED Indicators ................................................................................. 8
Soft Disable ..................................................................................... 8
iComfort Wi-Fi Commissioning (Conventional Outdoor Unit) .......... 9
iComfort S30 Commissioning (Conventional Outdoor Unit) ............ 9
Operating Environment Specications ............................................9
Unit Dimensions ...............................................................................10
Duel-Fuel Operations .......................................................................10
Field Wiring ....................................................................................... 11
Alert Codes and Troubleshooting...................................................17
WARNING
This product contains a chemical known to the State of California to
cause cancer, birth defects, or other reproductive harm.
TABLE OF CONTENTS Shipping and Packing List
Quantity Description
1 iComfort® Equipment Interface Module.
1 Installation and setup guide
1Warranty certicate
WARNING
Improper installation, adjustment, alteration, service or maintenance can
cause property damage, personal injury or loss of life.
Installation and service must be performed by a licensed professional
HVAC installer (or equivalent) or a service agency.
Application and Requirements
Indoor Transformer Requirements
The following tTable 1 lists the required indoor unit transformer rating (VA)
for specic congurations.
Table 1. System VA Loading Chart
Conguration Minimum Transformer Rating
(VA)
2-Stage HP, 3-Stage Electric heat 70
2-Stage HP, 2-Stage Furnace (with tempering) 70
2-Stage HP, 2-Stage Furnace (without tempering) 50
2-Stage AC, 2-Stage Furnace 40
Equipment
The Equipment Interface Module (EIM) is used with an iComfort series
thermostat (iComfort Wi-FI®or iComfort®S30) using the R, i+, i-, and C
terminals. The EIM is the interface between conventional (non-iComfort)
HVAC equipment and iComfort HVAC equipment. The control supports the
following equipment applications:
NOTE: EIM will support single-stage outdoor units with single-stage or
variable-stage indoor furnaces.

3
OUTDOOR AIR SENSOR
CONNECTIONS
DISCHARGE AIR
SENSOR CONNECTIONS
ICOMFORT
®
CONNECTIONS
NON-COMMUNICATING TERMINALS
STATUS LED
COMMUNICATION INDICATOR
LED
DUAL-FUEL
CONNECTIONS
UNIT TYPE JUMPER
TERMINALS
HEAT STAGES
JUMPER TERMIINALS HEAT PUMP CAPACITY
JUMPER TERMINALS
3 AMP FUSE
Figure 1. Terminals and LEDs

4
tions, additional components
may need to be added, see figure
5 on page 8.
iComfort Series
Thermostat
Equipment Interface
Model (EIM)
24VAC Air Handler or
Furnace (Indoor Unit)
iComfort-enabled
Air Conditioner or
Heat Pump
(Outdoor Unit)
Wiring Legend
4−wire communicating
24VAC conventional
EIM with Air Hander or Furnace (Indoor Unit)
and either a Air Conditioner or Heat Pump
(Outdoor Unit)
24VAC Air
Conditioner
or Heat Pump
(Outdoor Unit)
ICOMFORT
WI-FI
ICOMFORT
S30
Figure 2. System View

5
Installation
WARNING
Controls in this module are sensitive to moisture. Do NOT secure this
module to the sheet metal cabinet where moisture may condense during
periods of high humidity. Secure the module to a nearby wooden stud, if
possible.
IMPORTANT
The iComfort series thermostat paired with the Equipment Interface
Module (EIM) will work with most 24VAC furnaces, air handlers, air
conditioners and heat pumps (up to 2-stages of cooling and 3-stages of
heat).
The iComfort series thermostat without the Equipment Interface Module
(EIM) will work with Lennox branded communicating HVAC equipment.
1. Remove the module cover.
2. Mount the Equipment Interface Module (EIM) near the indoor unit.
3. Use the wiring diagrams reference in Table 10 on page 11 to complete
the wiring connections for the specic application and conguration.
CAUTION
Electrostatic discharge can affect electronic components.Take precautions
during unit installation and service to protect the unit’s electronic controls.
Precautions will help to avoid control exposure to electrostatic discharge
by putting the unit, the control and the technician at the same electrostatic
potential. Neutralize electrostatic charge by touching hand and all tools
on an unpainted unit surface before performing any service procedure
Conguration Setup
How the EIM is congured is determined by the system components.
NOTE: Changing jumper positions after the control has been powered-up
requires recommissioning for the change to be recognized.
NOTE: When the Equipment Interface Module is replaced,
recommissioning the iComfort series thermostat will also need to
be re-accomplished. See the iComfort series thermostat Setup
Guide for recommissioning procedure.
EIM, 24VAC Furnace and iComfort Heat Pump
1. Set the EIM Unit Type Jumper to IFC.
2. Set the EIM Heat Stage Jumper to the applicable number of furnace
heat stages.
3. Use the iComfort series thermostat to complete the commissioning
procedure.
EIM, iComfort Furnace and 24VAC Heat Pump
1. Set the EIM Unit Type Jumper to Heat Pump.
2. Set the EIM Heat Stage Jumper to the applicable number of heat pump
heating stages.
3. Wire according to gure 10.
4. Use the iComfort series thermostat to complete the commissioning
procedure.
NOTE: For two-stage heat pump go to the heat pump outdoor control,
locate J2 - 2ND STAGE LOCKIN and disable this function by
removing the installed jumper and relocating it to one pin only.

6
Unit Type Jumpers
Set the unit type jumper for the type of indoor unit being used (see gure
2 and table 4). The factory default setting is IFC. If jumper is missing from
header, alarm 130 is activated.
Table 2. Unit Type Jumpers Positions
Jumper
Position Indoor Unit Outdoor Unit
HP iComfort Furnace Conventional Heat Pump
IFC Conventional Furnace Conventional Heat Pump or air
conditioner
AHC Conventional Air Handler
HP IFC AHC
Figure 3. Unit Type Jumper Positions
Table 3. Unit Type Jumpers Positions
Label Function / Description
HP Equipment Interface Module—Heat Pump
IFC Equipment Interface Module—Furnace (factory default)
AHC Equipment Interface Module—Air Handler
Heat Stage Jumper Positions
The heating staging Jumper must be set for the number of stages of electric
heat (air handler) or the number of stage of gas heat (furnace) and stages
of heat pump. Using the heat stages jumper (see gure 3 and table 8).
The factory default setting is position 2. If jumper is missing from header,
alarm 130 is activated.
0 1 2 3
Figure 4. Heat Stage Jumper Positions
24VAC Heat Pump Size Setting
Heat pump size must be congured when using a non-communicating heat
pump using the Heat Pump Size jumper (see gure 4 and table 5). Factory
default setting is for 3.0 (3-ton). If jumper is missing from header, alarm 130
is activated.
1.
5
2.
0
2.
5
3.
0
3.
5
4.
0
5.
0
Figure 5. Conventional Heap Pump Capacity Jumper Setting
Air Temperature Sensor Connections
Refer to “Figure 1. Terminals and LEDs” on page 3 for various terminal
locations.
Table 4. Unit Type Jumpers Positions
Label Function / Description
Outdoor Air
Sensor
Show ambient temperatures (optional if weather feed is acceptable or
outdoor unit is a communicating unit; use X2658 Outdoor Sensor - 2 ter-
minals).
NOTE: Wiring distance between the EIM and the outdoor temperature
sensor can not exceed 150 feet (45 meters) when wired with
minimum 22AWG (Recommend) 18AWG dedicated two-
conductor thermostat cable.
Discharge Air
Sensor
Optional for diagnostics of indoor air; use 88K38 Discharge Air Sensor - 2
terminals.
iComfort Terminal Connections
Table 5. Unit Type Jumpers Positions
Label Function / Description
R 24VAC communication power Input
i+ Communication high – data line
i- Communication low – data line
C 24VAC communication common power Input

7
Heat Stage Jumpers
Use the following table to set the heat stage jumpers.
Table 6. Heat Stage Jumpers
Label
(Position)
Air Handler Heat
Stages Furnace Heat Stages Heat Pump Stages
Number of
Electric Heat
Stages
Stage
Percentage
Number of
Gas Stages
Stage
Percentage
Number of
Compressors
Stages
Stage
Percentage
0No Electric
Heat 0 1 100% 1 100%
1 1 100% 1 100% 1 100%
2
(default) 250%, 100% 270%. 100% 370%. 100%
3 3
33.5%,
66.5%,
100%
270%,
100% 370%. 100%
NOTE: If jumper is missing, setting defaults to single stage. Changing jumper position
after power-up requires recommission for the change to be recognized.
Dual-Fuel Terminal Connections
Table 7. Dual-Fuel Terminals
Label Description Function
DFTS Pre-coil discharge air tem-
perature (2 terminals)
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 airow, where
other accessories (such as humidiers,
UV lights, etc.) will not interfere with its ac-
curacy. Wiring distance between the EIM
and the discharge air sensor should not
exceed 10 feet when using 18AWG ther-
mostat wire.
W1-DEF Defrost signal input
This input is used in systems with non-com-
municating heat pumps for defrost indica-
tion. The input provides a nominal load of
50 mA, 24 VAC.
0Heat Pump Reversing Valve
(Powered for cooling)
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 cool-
ing operation, while the terminal is open for
heating operation.
B
Heat Pump Reserving
Valve
(Powered for heating)
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 operation, while the terminal is open
for cooling operation.

8
Conventional Terminal Connections
Table 8. Conventional Terminals
Label Description Function
W1 1st - stage heat output (1st stage gas heat output when congured as IFC
and 1st stage electric heat output when congured as AHC.
W2 2nd - stage heat output (2nd stage gas heat output when congured as IFC
and 2nd stage electric heat output when congured as AHC.
W3 3rd - stage heat output (3nd stage electric heat output when congured as
AHC)
GIndoor blower control (continuous fan) (monitoring only). G input may be connected to IAQ devices such as LVCS, HRV or ERV to turn the indoor
blower on and off.
Y2 2nd - stage compressor output
Y1 1st - stage compressor output
DS 24VAC dehumidication signal output. The DS terminal is powered when
there is not a dehumidication call.
CClass II, 24VAC transformer
common
R and C terminals are used to receive
power from the indoor unit and capable
of providing the power to the EIM and all
the associated loads. The R power in-
put uses a 3A fuse (Lennox part number
25J4901.
RClass II. 24VAC transformer
power
H24VAC humidier signal output
OHeat pump reversing valve
(24VAC = cool)
Used as reversing valve output for heat
pumps. The EIM uses a single-pole dual
throw relay to generate O and B signals.
Normally the O output is open and B out-
put 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 ter-
minal.
BHeat pump reversing valve
(24 VAC = heat)
LED Indicators
This control has two green LED to indicate status and communication
activity One LED is labeled Status and the other is labeled RSBUS.
RSBUS LED
The RSBus LED ashes when information is being communicated over the
RSBus.
Status LED
The following table lists all status LED information.
Table 9. Status LED (Green)
Green LED Function / Description
Steady On Remains steady ON until the device sends its start-up mes-
sage.
Blinks 3 second OFF and 1
second ON Soft disable state
Blinks 2 second ON and 2
second OFF
Service is being provided (W, Y or G relay is
ON, or G input ON
Blinks 1 second ON and 1
second OFF Alarm is present.
Soft Disable
Soft disabling is when the iComfort® thermostat nds an unknown control
such as a indoor or outdoor unit control, iHarmony®zoning system or
Equipment Interface Module (EIM) on the system communication bus. The
thermostat sends the unknown control a message to go into soft disable
mode until component is properly congured.
The iComfort®thermostat will not show any code for a soft disabled control.
When soft disabling occurs only the control that has been disabled will
display the blinking LED status. In this case, the control blinks three
seconds OFF and one second ON.
Use the following procedure if the equipment interface module is displaying
the soft disable code.
1. Conrm proper wiring between all devices such as thermostat, EIM,
indoor and outdoor unit).
2. Cycle power to the control that is displaying the soft disable code.
3. Touch the Lennox icon on the thermostat home screen and hold until
the installer warning screen appears.
4. Touch yes to continue.
5. Touch Setup and then conrm to continue.
6. Use this Thermostat? Touch press here to continue.
7. Touch the next button to continue past the next three screens.
8. From the System Devices list, touch reset ALL to reset all devices.
9. Touch the conrm button.
The thermostat will reboot and start through the setup process again.

9
IMPORTANT
If any jumpers were set incorrectly AFTER commissioning was
completed, then reposition jumpers to correct positions. Re-running
the commissioning procedure will be required at the iComfort series
thermostat.
iComfort Wi-Fi Commissioning (Conventional Outdoor Unit)
Both unit capacity and number of compressor stages are required to be
congured through the iComfort series thermostat. Once the outdoor unit
has been installed and connected to the equipment interface module, go to
the thermostat and start the conguration process.
1. From the system devices screen, touch the yes button to add or
remove non-communicating equipment.
2. A non-communicating device list will appear, select Outdoor Unit
Type and then touch edit.
3. Under Outdoor Unit Type, select the applicable 1 or 2-stage unit.
Touch save to continue.
4. Under non-communicating device list, select Outdoor Unit Capacity
and then touch edit.
5. Touch either the up or down arrows to selected the applicable Outdoor
Unit Capacity. Valid options are 18, 24, 30, 36, 42, 48 and 60. Touch
save to continue.
This completes the conguring of the conventional outdoor unit.
iComfort S30 Commissioning (Conventional Outdoor Unit)
Both unit capacity and number of compressor stages are required to be
congured through the iComfort series thermostat. Once the outdoor unit
has been installed and connected to the equipment interface module, go to
the thermostat and start the conguration process.
1. From the equipment found screen, touch the non-communication
equipment location to add non-communicating equipment.
Figure 6. Adding Conventional Outdoor Unit
2. A add/remove equipment screen will appear. Under Outdoor Unit
Type, select the applicable 1 or 2-stage unit.
3. Touch either the plus or minus buttons to selected the applicable
Outdoor Unit Capacity. Valid options are 18, 24, 30, 36, 42, 48 and
60.
4. Touch save to continue.
Operating Environment Specications
The Equipment Interface Module is designed to operate in the following
environmental conditions.
• Operating Temperature Range: 40°F to 176°F (40° C to 80°C).
• Shipping and Storage Temperature Range: 40° F to 185°F (40°C to
85°C).
• Operating Humidity Range: 10% to 90% non-condensing at 104°F.

10
Unit Dimensions
8” (203mm)
6” (152mm)
1-5/8” (42mm)
Figure 7. Unit Dimensions
Duel-Fuel Operations
To use the EIM in dual-fuel mode, the following equipment combinations
and conguration is required.
Defrost Air Tempering Kit (67M41) will be required. The included DT1
discharge temperature probe is inserted in the furnace air outlet between
the furnace and the indoor coil to keep the furnace from overheating the
coil which would cause heat pump high pressure tripping during the defrost
cycling. The DT1 is only needed with non-communicating furnaces and is
not required for air handlers.
Wiring example for the DT1 Discharge Temperature Probe is in “Figure 14.
Dual-Fuel - Conventional Furnace with Conventional Heat Pump” on page
12.
iComfort Series
Thermostat
Equipment Interface
Model (EIM)Furnace
24VAC conventional
DUAL−FUEL WITH DEFROST TEMPERING
(EIM, 24VAC Furnace and Communicating Heat Pump)
iComfort-enabled
Heat Pump
(Outdoor Unit)
Outdoor Sensor
(Included with
Heat Pump)
Defrost Tempering
(Available only if
furnace is variable
Optional
NOTE: iComfort Wi-Fi
Thermostat with firmware
version 2.1 or higher)
capacity
or multi-stage)
Wiring Legend
4-wire communicating
ICOMFORT
WI-FI
ICOMFORT
S30
Figure 8. EIM, Conventional Furnace and iComfort Heat Pump