Lennox EL180DFE Series Installation and operation manual

Page 1 ©2017 Lennox Industries Inc.
EL180DFE
Service Literature
Corp. 1301-L1
Revised 09/2017
EL180DFE series units are mid-efficiency gas furnaces
used for downflow applications only, manufactured with
Lennox Duraloktheat exchangers formed of aluminized
steel. EL180DFE units are available in heating capacities
of 44,000 to 110,000 Btuh and cooling applications 1.5 to 5
tons. Refer to Engineering Handbook for proper sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LP/Propane operation.
EL180DFE model units are equipped with a hot surface igni
tion system and a constant torque ECM motor. The motor is
programmed to provide constant torque at each of the five
selectable speed taps. All units use a redundant gas valve to
assure safety shut-off as required by C.S.A.
All specifications in this manual are subject to change. Pro
cedures outlined in this manual are presented as a recom
mendation only and do not supersede or replace local or
state codes. In the absence of local or state codes, the
guidelines and procedures outlined in this manual (except
where noted) are recommended only and do not constitute
code.
WARNING
Improper installation, adjustment, alteration, service
or maintenance can cause property damage, person
al injury or loss of life. Installation and service must
be performed by a licensed professional HVAC in
staller (or equivalent), service agency or the gas sup
plier.
TABLE OF CONTENTS
Specifications Page 2.............................
Blower Data Page 3..............................
Parts Identification Page 5.........................
I Unit Components Page 6........................
II Installation Page 17.............................
III Start Up Page 17..............................
IV Heating System Service Checks Page 17.........
V Typical Operating Characteristics Page 21.........
VI Maintenance Page 21..........................
VII Wiring and Sequence of Operation Page 24......
WARNING
Electric shock hazard. Can cause injury
or death. Before attempting to perform
any service or maintenance, turn the
electrical power to unit OFF at discon
nect switch(es). Unit may have multiple
power supplies.
WARNING
Fire Hazard. Use of aluminum wire with this
product may result in a fire, causing property dam
age, severe injury or death. Use copper wire only
with this product.
CAUTION
Failure to use properly sized wiring and circuit
breaker may result in property damage. Size wiring
and circuit breaker(s) per Product Specifications
bulletin (EHB) and unit rating plate.
CAUTION
As with any mechanical equipment, contact with
sharp sheet metal edges can result in personal in
jury. Take care while handling this equipment and
wear gloves and protective clothing.

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. EL180DF045E36A EL180DF070E36B EL180DF090E48B EL180DF110E60C
1AFUE 80% 80% 80% 80%
Input - Btuh 44,000 66,000 88,000 110,000
Output - Btuh 35,200 52,800 70,400 88,000
Temperature rise range - °F 15 - 45 30 - 60 30 - 60 30 - 60
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
High Static - in. w.g. 0.50 0.50 0.50 0.50
Connections
in.
Flue connection - in. round 4444
Gas pipe size IPS 1/2 1/2 1/2 1/2
Indoor
Blower
Wheel nom. dia. x width - in. 10 x 8 10 x 10 10 x 10 11-1/2 x 10
Motor output - hp 1/2 1/2 3/4 1
Tons of add-on cooling 1.5 - 3 1.5 - 3 2.5 - 4 3 - 5
Air Volume Range - cfm 355 - 1430 310 - 1345 680 - 1750 990 - 2410
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 6.8 6.8 8.4 10.9
Maximum overcurrent protection 12 12 12 12
Shipping Data lbs. - 1 package 113 128 140 160
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
1 Annual Fuel Utilization Efciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces.
OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA
“A” Width
Models
“B” Width
Models
“C” Width
Models
CABINET ACCESSORIES
Downow Combustible Flooring Base 11M59 11M60 11M61
FILTERS
1 Downow Filter Cabinet 51W06 51W07 51W08
No. and Size of lter - in. (1) 20 x 16 x 1 (2) 20 x 20 x 1 (2) 20 x 20 x 1
NIGHT SERVICE KITS
Night Service Kit 84W47 84W47 84W47
Safety Service Kit 89W19 89W19 89W19
1 Cleanable polyurethane, frame-type lter.
GAS HEAT ACCESSORIES
Input
High Altitude
Pressure Switch Kit
Natural Gas to
LPG/Propane Kit
LPG/Propane
to Natural Gas Kit
Natural Gas
High Altitude
Orice Kit
0 - 4500 ft. 4501 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 7501 - 10,000 ft.
045 No Change No Change 80W51 11K49 11K44 73W81 73W37
070 No Change 80W52 80W51 11K49 11K44 73W81 73W37
090 No Change 80W52 80W51 11K49 11K44 73W81 73W37
110 No Change 80W57 80W52 11K49 11K44 73W81 73W37

Page 3
BLOWER DATA
EL180DF045E36A PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1430 285 1215 180 1035 120 995 110 930 100
0.10 1400 285 1175 185 995 130 885 100 850 90
0.20 1375 300 1145 200 950 140 840 110 725 85
0.30 1335 315 1120 210 915 145 790 115 665 95
0.40 1320 325 1075 220 870 155 745 125 625 100
0.50 1275 335 1045 230 835 165 715 135 565 105
0.60 1245 345 1000 235 785 170 655 140 520 115
0.70 1215 355 970 245 745 180 605 150 355 130
0.80 1175 365 925 255 695 185 555 155 400 130
EL180DF070E36B PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1475 275 1345 170 1225 135 1185 125 1110 105
0.10 1430 290 1275 175 1190 145 1155 135 1005 95
0.20 1400 295 1230 190 1125 160 1110 150 900 100
0.30 1360 310 1205 205 1085 160 1055 155 845 115
0.40 1310 325 1155 210 1050 175 1000 165 790 115
0.50 1280 335 1110 220 985 185 950 180 705 130
0.60 1250 350 1060 235 935 195 865 185 645 135
0.70 1220 355 1000 245 865 205 815 195 590 140
0.80 1165 365 935 250 795 210 750 200 480 145
EL180DF090E48B PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 1750 385 1550 265 1430 205 1355 185 1195 130
0.10 1725 390 1495 270 1390 220 1320 195 1145 140
0.20 1695 405 1470 285 1340 235 1280 210 1105 145
0.30 1660 415 1425 300 1290 240 1225 215 1040 160
0.40 1615 430 1395 310 1250 255 1185 230 1005 170
0.50 1570 450 1360 325 1210 265 1145 240 945 180
0.60 1545 465 1295 340 1165 280 1085 255 865 185
0.70 N/A N/A 1265 350 1120 295 1040 265 810 200
0.80 N/A N/A 1215 365 1080 305 1000 275 755 210

Page 4
BLOWER DATA
EL180DF110E60C PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Various Blower Speeds
High Medium-High Medium Medium-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2410 625 2095 405 1875 295 1700 225 1635 180
0.10 2385 630 2100 415 1830 310 1610 240 1505 190
0.20 2325 650 2010 440 1760 330 1570 255 1375 195
0.30 2280 675 1940 460 1705 340 1500 260 1320 210
0.40 2235 690 1895 475 1635 365 1440 285 1265 225
0.50 2165 710 1845 490 1595 380 1380 300 1200 235
0.60 2125 735 1800 510 1545 390 1320 310 1170 250
0.70 2090 740 1755 530 1510 405 1285 325 1100 260
0.80 2035 760 1700 540 1460 425 1255 345 1030 275

Page 5
EL180DFE PARTS ARRANGEMENT
FIGURE 1
Primary Limit
(under combustion
air inducer)
Gas Valve
Burner Box
(includes sensor, ignitor
and rollout switches)
Combustion
Air Inducer
Heat Exchanger
Flue Chase
Blower Assembly
Secondary Limit
Access Panel
Control Box
(includes integrated control, transformer,
inter lock switch and circuit breaker)

Page 6
I-UNIT COMPONENTS
EL180DFE unit components are shown in figure 1.The gas
valve, combustion air inducer and burners can be ac
cessed by removing the heating compartment access pan
el. Electrical components are in the control box (figure 2)
found in the blower section.
WARNING
Electric Shock Hazard. Can cause
injury or death. Unit must be properly
grounded in accordance with national
and local codes.
CAUTION
Electrostatic discharge can affect elec
tronic components. Take precautions
to neutralize electrostatic charge by
touching your hand and tools to metal
prior to handling the control.
1. Control Transformer (T1)
A transformer located in the control box provides power to
the low voltage section of the unit. Transformers on all
models are rated 40VA with a 120V primary and a 24V sec
ondary.
2. Door Interlock Switch (S51)
A door interlock switch is wired in series with line voltage.
When the blower door is removed the unit will shut down.
FIGURE 2
CONTROL BOX EL180DFE
DOOR INTERLOCK
SWITCH (S51)
INTEGRATED CONTROL
(A92)
TRANSFORMER
(T1)
CIRCUIT
BREAKER
(CB8)
3. Circuit Breaker (CB8)
A 24V circuit breaker is also located in the control box. The
switch provides overcurrent protection to the transformer
(T1). The breaker is rated at 3A at 32V. If the current ex
ceeds this limit the breaker will trip and all unit operation will
shutdown. The breaker can be manually reset by pressing
the button on the face.
4. Integrated Control (A92)
WARNING
Shock hazard.
Disconnect power before servicing. Control is not
field repairable. If control is inoperable, simply re
place entire control.
Can cause injury or death. Unsafe operation will re
sult if repair is attempted.
The hot surface ignition control system consisting of an in
tegrated control (figure 3 with control terminal designa
tions in tables 1, 2 and 3), flame sensor and ignitor (figure
6). The integrated control and ignitor work in combination
to ensure furnace ignition and ignitor durability. The inte
grated control, controls all major furnace operations. The
integrated control also features a RED LED for trouble
shooting and two accessory terminals rated at (1) one
amp. See table 4 or 5 for troubleshooting diagnostic
codes. The nitride ignitor is made from a non-porous, high
strength proprietary ceramic material that provides long
life and trouble free maintenance.
Electronic Ignition (Figure 4)
On a call for heat the integrated control monitors the com
bustion air inducer pressure switch. The control will not be
gin the heating cycle if the pressure switch is closed (by-
passed). Once the pressure switch is determined to be
open, the combustion air inducer is energized. When the
differential in the pressure switch is great enough, the pres
sure switch closes and a 15-second pre-purge begins. If
the pressure switch is not proven within 2-1/2 minutes, the
integrated control goes into Watchguard-Pressure Switch
mode for a 5-minute re-set period.
After the 15-second pre-purge period, the ignitor warms up
for 20 seconds during which the gas valve opens at 19 sec
onds for a 4-second trial for ignition. The ignitor remains
energized for the first 3 seconds during the 4 second trial. If
ignition is not proved during the 4-second period, the inte
grated control will try four more times with an inter purge
and warm-up time between trials of 35 seconds. After a to
tal of five trials for ignition (including the initial trial), the inte
grated control goes into Watchguard-Flame Failure mode.
After a 60-minute reset period, the integrated control will
begin the ignition sequence again.

Page 7
TABLE 1
4-Pin Terminal Designation
PIN # FUNCTION
1Combustion Air Inducer Line
2Ignitor Line
3Combustion Air Inducer Neutral
4Ignitor Neutral
TABLE 2
12-Pin Terminal Designations
PIN # FUNCTION
1High Limit Output
2Not Used
324V Line
4Not Used
5Rollout Switch Out
624V Neutral
7High Limit Input
8 Ground
9Gas Valve Common
10 Pressure Switch In
11 Rollout Switch In
12 Gas Valve Out
TABLE 3
1/4” QUICK CONNECT TERMINALS
120HUM Humidifier 120VAC
LINE 120VAC
XFMR Transformer 120VAC
CIRC Indoor blower 120VAC
EAC Indoor air quality accessory 120VAC
NEUTRALS Common 120VAC
HUM24 Humidifier 24VAC
3/16” QUICK CONNECT TERMINALS
COOL Cooling tap 24VAC
HEAT Heating tap 24VAC
FAN Continuous blower 24 VAC
PARK (no power) Park terminal for speed taps
FS Flame sense
24 COM Common 24VAC
FIGURE 3
INTEGRATED CONTROL
(Automatic Hot Surface Ignition System)
BLOWER OFF DELAY
RED LED RECALL BUTTON

Page 8
TABLE 4 (-02 Integrated Control)
RED LED
Flash Code Diagnostic Codes / Status of Furnace
Off No power to control or board fault detected
Heartbeat1Control powered - displayed during all modes of operation if no errors are detected
1Reverse Line Voltage Polarity
2Improper Earth Ground
3Burner failed to light, or lost flame during heat demand
4Low Flame Signal - check flame sensor
5Watchguard - burner failed to light, exceeded maximum number of retries or recycles.
6Not Used
7Primary or Secondary Limit Open or Watchguard Mode - Limit Switch Open longer than 3 minutes
8Rollout Switch Open
9Pressure Switch failed to close or opened during heat demand
10 Watchguard - Pressure Switch opened 5 times during one heat demand
11 Pressure Switch stuck closed prior to activation of combustion air inducer
12 Flame Sensed without gas valve energized
13 Low Line Voltage
Notes
Note 1 A ”Heartbeat” is indicated by a ”Slow Flash” - 1 sec on 1 sec off, repeating
Note Error codes are indicated by a ”Rapid Flash” - the LED flashes X times at 1/2 sec on 1/2 sec off, remains off for 3 sec,
then repeats
Note
Last 10 error codes are stored in memory including when power is shut off to the unit. - To recall, press and release button,
most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress
and hold button longer than 5 seconds.
TABLE 5 (-03 Integrated Control)
RED LED
Flash Code2Diagnostic Codes / Status of Furnace
Off No power to control or board fault detected
Heartbeat1Normal Operation - Idle, Continuous Fan, Cool
Continuous Rapid Flash Call For Heat / Burner Operation
1Reverse Line Voltage Polarity
2Improper Earth Ground
3Burner failed to light, or lost flame during heat demand
4Low Flame Signal - check flame sensor
5Watchguard - burner failed to light, exceeded maximum number of retries or recycles.
6Ignitor Circuit Failure - not available on this control
7Primary or Secondary Limit Open or Watchguard Mode - Limit Switch Open longer than 3 minutes
8Rollout Switch Open
9Pressure Switch failed to close or opened during heat demand
10 Watchguard - Pressure Switch opened 5 times during one heat demand
11 Pressure Switch stuck closed prior to activation of combustion air inducer
12 Flame Sensed without gas valve energized
13 Low Line Voltage
Notes
Note 1 A ”Heartbeat” is indicated by a ”Slow Flash” - 1 sec on 1 sec off, repeating
Note 2 Error codes are indicated by a “rapid flash” - the LED flashes X times at ½ second on ½ second off, remains off for 3
seconds then repeats.
Note3
Last 10 error codes are stored in memory including when power is shut off to the unit. - To recall, press and release button,
most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress
and hold button longer than 5 seconds.

Page 9
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉ
DEMAND
CAI
GAS VALVE
15
ON
OFF
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉ
38
ÉÉÉÉÉÉÉÉÉÉ
IGNITOR
341
Pre -Purge Ignitor Warm-up Trial for
Ignition Post
Purge
5 SEC80
*Blower on time will be 30 seconds after flame is sensed. Blower off time will depend on “OFF TIME” Setting.
INDOOR BLOWER
ÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉ
Blower “On”*
Delay
ELECTRONIC IGNITION
FIGURE 4
Fan Time Control
Heating Fan On Time
The fan on time of 30 seconds is not adjustable.
Heating Fan Off Time
Fan off time (time that the blower operates after the heat
demand has been satisfied) can be adjusted by moving the
jumper to a different setting. The unit is shipped with a fac
tory fan off setting of 90 seconds. For customized comfort,
monitor the supply air temperature once the heat demand
is satisfied. Note the supply air temperature at the instant
the blower is de-energized.
Adjust the fan-off delay to achieve a supply air temperature
between 90° - 110° at the instant the blower is de-ener
gized. (Longer delay times allow for lower air temperature,
shorter delay times allow for higher air temperature). See
figure 5.
Cooling Fan On Time
The fan on time is 2 seconds and is not adjustable.
Cooling Fan Off Time
The control has a 45 second fan off delay after cooling de
mand has been met. This delay is factory set and not ad
justable.
HEAT FAN‐OFF TIME IN SECONDS
To adjust fan-off timing, reposition jumper across pins to
achieve desired setting.
NO JUMPER
FIGURE 5
60 90
120
180
60 90
120
180
60 90
120
180
60 90
120
180
60 Second
off Time
90 Second
off Time
120 Second
off Time
180 Second
off Time

Page 10
EL180DFE HEATING COMPONENTS
FIGURE 6
Gaskets
Collector Box
Orifice Plate
Pressure Switch
Combustion Air Inducer
Internal Flue Pipe
Sensor
Rollout Switch
Rollout Switch
(Alternate Location)
Gas Valve / Manifold Assembly
Ignitor
5. Flame Rollout Switches (Figure 6)
Flame rollout switch (S47) is a high temperature limit. Each
furnace is equipped with two identical switches. The limit is
a N.C. SPST manual‐reset limit connected in series with
the integrated control A92. When S47 senses rollout, the
integrated control immediately stops ignition and closes
the gas valve. If unit is running and flame rollout is detected,
the gas valve will close and integrated control will be dis
abled. Rollout can be caused by a blocked heat exchanger,
blocked flue or lack of combustion air. The switch has a fac
tory setpoint of 210°F and cannot be adjusted. To manually
reset a tripped switch, push the reset button located on the
control.
6. Primary Limit Control
The primary limit on EL180DFE units is located in the heating
vestibule panel under the combustion air inducer. See figure 1.
When excess heat is sensed in the heat exchanger, the limit
will open. If the limit is open, the integrated control energizes
the supply air blower and closes the gas valve. The limit auto
matically resets when unit temperature returns to normal. The
switch must reset within three minutes or SureLight®control
will go into Watchguard for one hour. The switch is factory
set and cannot be adjusted. The switch may have a different
setpoint for each unit model number. If limit switch must be
replaced, refer to Lennox ProductZone repair parts list on
Lennox DaveNet®.
7. Flame Sensor (Figure 6)
A flame sensor is located on the left side of the burner sup
port. The sensor is mounted on the flame rollout plate and
the tip protrudes into the flame envelope of the left-most
burner. The sensor can be removed for service (clean us
ing steel wool) without removing any part of the burners.
During operation, flame is sensed by current passed
through the flame and sensing electrode. The integrated
control allows the gas valve to remain open as long as
flame signal is sensed.
A microamp DC meter is needed to check the flame signal
on the integrated control.
Flame (microamp) signal is an electrical current which passes
from the integrated control to the sensor during unit operation.
Current passes from the sensor through the flame to ground to
complete a safety circuit.

Page 11
To Measure Flame Signal - Integrated Control:
Use a digital readout meter capable of reading DC micro
amps. See figure 7 and table 6 for flame signal check.
1 - Set the meter to the DC amps scale.
2 - Turn off supply voltage to control.
3 - Remove sensor wire from integrated control.
4 - Connect (-) lead to flame sensor wire.
5 - Connect (+) lead to Terminal FS on integrated control.
6 - Turn supply voltage on and close thermostat contacts to
cycle system.
7 - When main burners are in operation for two minutes, take
reading.
TABLE 6
Flame Signal in Microamps
Normal Low Drop Out
1.5 0.5 - 1.4 0.4
FIGURE 7
Measuring Flame Signal
(upflow furnace shown)
Flame
Sensor
Flame Sensor
Wire
Integrated
Control
Remove Sensor Wire from
Integrated Control and
Connect Alligator Clip (−)
to Flame Sensor Lead
Flame Sensor
Terminal
Remove Sensor Wire from
Integrated Control and
Connect Alligator Clip (+)
to Terminal on Control
(+)
DIGITAL METER
(+) To Control
Sensor
Terminal
(−) To
flame
sensor
Set dial to measure dc microamps
(+)
Red Collar
Indicates
Positive Lead

Page 12
8. Ignitor (Figure 6)
The nitride ignitor used on EL180DFE units is made from a
proprietary ceramic material. To check ignitor, measure its
resistance and voltage. A value of 39 to 70 ohms indicates
a good ignitor. Voltage to the ignitor should be 120VAC.
See figure 8 for resistance, and voltage check.
NOTE - The EL180DFE furnace contains electronic
components that are polarity sensitive. Make sure that
the furnace is wired correctly and is properly grounded.
FIGURE 8
Test 1
Check ignitor circuit for correct resistance.
Remove 4-pin plug from control.
Check ohms reading across terminals 2 and 4.
If value is correct (39 to 70 ohms), this is the only test
needed.If the reading on the meter is not correct,
(0 or infinity) then a second test is needed.
Test 2
Check ignitor for correct resistance.
Seperate the 2-pin jack-plug near the manifold and check
resistance of ignitor at the plug. Reading should be
between 39 and 70 ohms. If the reading is correct, then
the problem is with the wiring between the jack-plug and
the control. If reading is not correct, the issue is the ignitor.
Test 3
Check ignitor for correct voltage
Insert meter probes into terminals 2 and 4 (use small
diameter probes in order not to damage plug).
Check voltage during 20 second ignitor warm up period.
Voltage should read 120 volts + 10%. If voltage reads below
these values, check for correct supply voltage to furnace.
Integrated Control B
o
Detail
Test 1
Integrated Control Board
Detail
Integrated Control Board
Detail

Page 13
9. Gas Valve (Figure 6)
The EL180DFE uses internally redundant gas valve to as
sure safety shut-off. If the gas valve must be replaced, the
same type valve must be used.
24VAC terminals and valve switch are located on the valve. All
terminals on the gas valve are connected to wires from the in
tegrated control. 24V applied to the terminals energizes the
valve.
Inlet and outlet pressure taps are located on the valve. A regu
lator adjustment screw is located on the valve.
LPG changeover kits are available from Lennox. Kits include
burner orifices and a gas valve regulator spring.
10. Combustion Air Inducer (B6)
All EL180DFE units use a combustion air inducer to move
air through the burners and heat exchanger during heating
operation. The blower uses a 120VAC motor. The motor
operates during all heating operation and is controlled by
integrated control A92. The inducer also operates for 15
seconds before burner ignition (pre‐purge) and for 5 sec
onds after the gas valve closes (post‐purge).
A pressure switch mounted on the combustion air inducer ori
fice plate is used to prove inducer operation. The combustion
air inducer orifice will be different for each model. See table 7
for orifice sizes. The switch monitors air pressure in the induc
er housing. During normal operation, the pressure in the
housing is negative. If pressure becomes less negative (sig
nifying any obstruction in the flue) the pressure switch opens.
When the proving switch opens, the integrated control (A92)
immediately de-energizes the gas valve to prevent burner
operation.
TABLE 7
EL180DFE Unit C.A.I. Orifice Size
045E36A 1.045”
070E36B 1.316”
090E48B 1.531”
110E60C 1.690”
11. Combustion Air Inducer
Pressure Switch (S18)
EL180DFE series units are equipped with a combustion air
pressure switch located on the combustion air inducer ori
fice bracket. The switch is connected to the combustion air
inducer housing by means of a flexible silicone hose. It mon
itors negative air pressure in the combustion air inducer
housing.
The switch is a single‐pole single‐throw proving switch elec
trically connected to the furnace control. The purpose of the
switch is to prevent burner operation if the combustion air in
ducer is not operating or if the flue becomes obstructed.
On start‐up, the switch senses that the combustion air in
ducer is operating. It closes a circuit to the integrated con
trol when pressure inside the combustion air inducer de
creases to a certain set point. Set points vary depending on
unit size. See table 8. The pressure sensed by the switch is
negative relative to atmospheric pressure. If the flue be
comes obstructed during operation, the switch senses a
loss of negative pressure (pressure becomes more equal
with atmospheric pressure) and opens the circuit to the in
tegrated control and gas valve. A bleed port on the switch
allows relatively dry air in the vestibule to purge switch tub
ing, to prevent condensate build up.
TABLE 8
EL180DFE inches w.c.
Make Break +0.05
045E36A -0.75 -0.60
070E36B -0.80 -0.65
090E48B -0.75 -0.60
110E60C -0.80 -0.65
The switch is factory set and is not field adjustable. It is a
safety shut‐down control in the furnace and must not be by-
passed for any reason. If switch is closed or by-passed, the
integrated control will not initiate ignition at start up.
Troubleshooting
See figure 9 for measuring operating pressure and check
ing resistance in the pressure switch.
FIGURE 9
MULTI−METER
SET TO MEASURE OHMS
+-
or
Field Provided Tubing
To CAI Port
To Pressure Switch
Remove tubing from
CAI and insert “Tee”
and additional tubing.
High
Low

Page 14
12. Blower Motor
IMPORTANT
Each blower is statically and dynamically bal
anced as an assembly before installation in the
unit.
EL180DFE units are equipped with a constant torque ECM
motor. It has a DC motor coupled to an electronic control
module both contained in the same motor housing. The mo
tor is programmed to provide constant torque at each of the
five selectable speed taps. Each tap requires 24 volts to en
ergize.
Input Voltage Requirements
The circuit is designed to be operated with AC voltage. To
enable a tap requires 12 to 33VAC. Expected current draw
will be less than 20mA.
Troubleshooting the Motor
Troubleshooting the motor is an easy process. Follow
steps below.
1- Shut off power to unit.
2- Remove input plugs P48 and P49 from motor. See
figure 13 for troubleshooting procedure.
If correct voltage is present in tests 1 and 2 and motor is not
operating properly, replace motor. The motor is not field re
pairable.
If replacing the indoor blower motor or blower wheel is nec
essary, placement is critical. The blower wheel must be cen
tered in the blower housing as shown in figure 10. When re
placing the indoor blower motor the set screw must be
aligned and tightened with the motor shaft as shown in figure
11.
13. Secondary Limit Controls
The secondary limit is located in the blower compartment on
the back side of the blower housing. See figure 12. When ex
cess heat is sensed in the blower compartment, the limit will
open. If the limit is open, the furnace control energizes the sup
ply air blower and closes the gas valve. The limit automatically
resets when unit temperature returns to normal. The secon
dary limit cannot be adjusted.
FIGURE 10
Center Blower Wheel
in Blower Housing
BLOWER WHEEL REPLACEMENT
FIGURE 11
Set Screw
Housing Hub
ALIGN AND TIGHTEN SET SCREW WITH
FLAT SIDE OF MOTOR SHAFT
Motor
Shaft
FIGURE 12
SECONDARY LIMIT CONTROL
Blower Assembly
Secondary Limit

Page 15
1
2
3
4
5
C
L
G
N
Multi−Meter
(set to VAC)
P48
P49
120 120
Turn on power to unit. Check for 120 volts across terminals
“L” and “N” on input plug P48. If voltage is present continue
to test 2. If voltage is not present problem may be may be up
stream of plug P48 and proceed to test 3.
1
2
3
4
5
C
L
G
N
Multi−Meter
(set to VAC)
P48
P49 24
Switch thermostat to CONTINUOUS FAN MODE. Check for
24 volts across terminal “C” on inpult plug P48and speed tap
used for continuous fan. (1, 2, 3, 4 or 5) on input plug P49. If
24 volts is not present problem may be up stream of plug P49.
Proceed to test 4.
Multi−Meter
(set to VAC)
120 120
24
Multi−Meter
(set to VAC)
Check for 24 volts across terminals “24 COM” and “FAN” ter
minals on the integrated control. If voltage is present, prob
lem is with the harness. If voltage is not present problem
may be may be with the integrated control
Check for 120 volts across terminals “CIRC” and “Neutrals”
on the integrated control. If voltage is present, problem is
with the harness. If voltage is not present problem may be
may be with the integrated control.
Test 1
Test 2
Test 3 (if necesssary)
Test 4 (if necessary)
FIGURE 13

12
3
4
5
6
7
8
9
10
11 12
1/16
TURN
Page 16
Replacing the Motor Module
1. Disconnect electrical power to unit.
2. Remove unit access panel.
3. Unplug the two harnesses from the motor control mod
ule. See figure 14.
TWO HARNESS
CONNECTIONS
MOTOR CONTROL MODULE
MOTOR
FIGURE 14
Unplug the Two Harness Connection
4. Remove the two hex head bolts securing the motor
control module to the motor (see figure 15).
REMOVE BOTH HEX
HEAD BOLTS
FIGURE 15
Remove the Hex Head Bolts
5. Slide the motor control module away from the motor to
access and disconnect the internal three wire connec
tor. It is not necessary to remove blower motor itself.
Set both hex head bolts aside.
Testing the Motor (Figure16)
If any motor fails the below tests, do not install the new con
trol module. The motor is defective and it also must be re
placed. The new control can fail if placed on a defective mo
tor.
1. Using an ohmmeter check the resistance from any one
of the motor connector pins to the aluminum end plate
of the motor. This resistance should be greater than
100k ohms.
2. Check the resistances between each of the three mo
tor connector pins. These should all read approxim
ately the same resistance within an ohm.
3. Check to see if the blower wheel spins freely.
FIGURE 16
Motor Test
TABLE 9
Scale Measurement range in
words ohms
2 M two megohm-two million
ohms 0 - 2,000,000
200 K two hundred kilo-ohm-two
hundred thousand ohms 0 - 200,000
20 K twenty kilo-ohm-twenty
thousand ohms 0 - 20,000
2 K two kilo-ohm two-thousand
ohms 0 - 2,000
200 two hundred ohms 0 - 200
Motor Module Installation
All replacement motor control modules look similar; how
ever, each module is designed for a specific motor size. It is
very important to make sure that you are using the correct
replacement motor control module. USE OF THE WRONG
MOTOR CONTROL MODULE MAY RESULT IN UNEX
PECTED UNIT OPERATION.
1. Verify electrical power to unit is disconnected.
2. Connect three-wire harness from motor to control
module.
3. Mount new motor control module
to motor using two hex head bolts
removed in figure 15. Torque bolts
to 22 inch pounds or 1/16th clock
turn as exampled to the right.
4. Reconnect the two harnesses to
the motor control module.
5. The electrical connectors of the motor should be facing
down to form a drip loop (figure17). This will directs
moisture away from the motor and its electric connec
tions on the motor.
CONNECTOR
ORIENTATION
BETWEEN 4 AND 8
O'CLOCK
BACK OF CONTROL
MODULE
DRIP LOOP
FIGURE 17
Drip Loop

Page 17
II- PLACEMENT AND INSTALLATION
Make sure unit is installed in accordance with installation
instructions and applicable codes.
III- START‐UP
A- Heating Start‐Up
WARNING
Shock and burn hazard.
EL180DFE units are equipped with a hot surface
ignition system. Do not attempt to light manually.
Gas Valve Operation
FIGURE 18
GAS VALVE SHOWN IN ON POSITION
MANIFOLD
PRESSURE
OUTLET
PORT
INLET
PRESSURE
PORT
MANIFOLD
PRESSURE
ADJUSTMENT
SCREW
1 - STOP! Read the safety information at the beginning of
this section.
2 - Set the thermostat to the lowest setting.
3 - Turn off all electrical power to the unit.
4 - This furnace is equipped with an ignition device which
automatically lights the burners. Do not try to light the
burners by hand.
5 - Remove the heating compartment access panel.
6 - Move gas valve switch to OFF position. Do not
force. See figure 18.
7 - Wait five minutes to clear out any gas. If you then smell
gas, STOP! Immediately call your gas supplier from a
neighbor's phone. Follow the gas supplier's instruc
tions. If you do not smell gas go to next step.
8 - Move gas valve switch toON position. Do not force.
See figure 18.
9 - Replace the heating compartment access panel.
10- Turn on all electrical power to to the unit.
11- Set the thermostat to desired setting.
NOTE - When unit is initially started, steps 1 through 11
may need to be repeated to purge air from gas line.
12- If the appliance will not operate, follow the instructions
“Turning Off Gas to Unit” and call the gas supplier.
Turning Off Gas to Unit
1 - Set the thermostat to the lowest setting.
2 - Turn off all electrical power to the unit if service is to be
performed.
3 - Remove the heating compartment access panel.
4 - Move gas valve switch to OFF position. Do not
force. See figure 18.
5 - Replace the heating compartment access panel.
B- Safety or Emergency Shutdown
Disconnect main power to unit. Close manual and main gas
valves.
C- Extended Period Shutdown
Turn off thermostat or set to “UNOCCUPIED” mode. Close
all gas valves (both internal and external to unit) to guaran
tee no gas leaks into combustion chamber. Turn off power
to unit. All access panels and covers must be in place and
secured.
IV-HEATING SYSTEM SERVICE CHECKS
A- C.S.A. Certification
All units are C.S.A. design certified without modifications.
Refer to the EL180DFE Installation Instruction.
B- Gas Piping
Gas supply piping should not allow more than 0.5”W.C. drop
in pressure between gas meter and unit. Supply gas pipe
must not be smaller than unit gas connection.
Compounds used on gas piping threaded joints should be
resistant to action of liquefied petroleum gases.
C- Testing Gas Piping
CAUTION
If a flexible gas connector is required or allowed by
the authority that has jurisdiction, black iron pipe
shall be installed at the gas valve and extend outside
the furnace cabinet.
IMPORTANT
In case emergency shutdown is required, turn off
the main shut‐off valve and disconnect the main
power to unit. These controls should be properly
labeled by the installer.
WARNING
Do not over torque (800 in-lbs) or under torque (350
in-lbs) when attaching the gas piping to the gas
valve.
When pressure testing gas lines, the gas valve must be dis
connected and isolated. Gas valves can be damaged if
subjected to more than 0.5 psig (14” W.C.). See figure 19. If
the pressure is equal to or greater than 0.5 psig (14”W.C.),
close the manual shut-off valve before pressure testing to
isolate furnace from gas supply.

Page 18
FIGURE 19
MANUAL MAIN SHUT-OFF VALVE
WILL NOT HOLD TEST PRESSURE
IN EXCESS OF 0.5 PSIG (14”W.C.)
GAS VALVE
CAP
GAS PIPING TEST PROCEDURE
FIELD PROVIDED
LINE PRESSURE TAP
When checking piping connections for gas leaks, use pre
ferred means. Kitchen detergents can cause harmful corro
sion on various metals used in gas piping. Use of a specialty
Gas Leak Detector is strongly recommended. It is available
through Lennox under part number 31B2001. See Corp.
8411-L10, for further details.
Do not use matches, candles, flame or any other source of
ignition to check for gas leaks.
D- Gas Pressure Adjustment
Gas Flow (Approximate)
TABLE 10
GAS METER CLOCKING CHART
EL180DFE
Unit
Seconds for One Revolution
Natural LP
1 cu ft
Dial
2 cu ft
Dial
1 cu ft
Dial
2 cu ft
DIAL
-045 80 160 200 400
-070 55 110 136 272
-090 41 82 102 204
-110 33 66 82 164
-135 27 54 68 136
Natural-1000 btu/cu ft LP-2500 btu/cu ft
Furnace should operate at least 5 minutes before check
ing gas flow. Determine time in seconds for two revolu
tions of gas through the meter. (Two revolutions assures a
more accurate time.) Divide by two and compare to time
in table 10. If manifold pressure matches table 12 and rate
is incorrect, check gas orifices for proper size and restric
tion. Remove temporary gas meter if installed.
NOTE - To obtain accurate reading, shut off all other gas
appliances connected to meter.
E- Supply and Manifold Pressure
Supply Pressure Measurement
1 - Remove the threaded plug from the inlet side of the
gas valve and install a field-provided barbed fitting.
Connect to a test gauge to measure supply pressure.
2 - Start unit and allow 5 minutes for unit to reach steady
state.
3 - After allowing unit to stabilize for 5 minutes, record
supply pressure and compare to value given in table
12.
Manifold Pressure Measurement
1 - Remove the threaded plug from the outlet side of the
gas valve and install a field-provided barbed fitting.
Connect to a test gauge to measure manifold pres
sure.
2 - Start unit and allow 5 minutes for unit to reach steady
state.
3 - While waiting for the unit to stabilize, observe the
flame. Flame should be stable and should not lift from
burner. Natural gas should burn blue.
4 - After allowing unit to stabilize for 5 minutes, record
manifold pressure and compare to value given in table
12.
5 - Shut unit off and remove manometer as soon as an ac
curate reading has been obtained. Take care to re
place pressure tap plug.
6 - Start unit and perform leak check. Seal leaks if found.
F- Proper Combustion
Furnace should operate a minimum 15 minutes with cor
rect manifold pressure and gas flow rate before checking
combustion. Take combustion sample beyond the flue out
let and compare to the tables below. The maximum carbon
monoxide reading should not exceed 100 ppm.
TABLE 11
EL180DFE Unit CO2%For Nat CO2% For LP
045
6.8 - 7.4 7.5 - 9.0
070
090
110
The maximum carbon monoxide reading is 100 ppm.
G- High Altitude
The manifold pressure may require adjustment and com
bustion air pressure switch may need replacing to ensure
proper combustion at higher altitudes. Refer to table 12 for
manifold pressure and table 13 for pressure switch change
and gas conversion kits.
IMPORTANT
For safety, shut unit off and remove manometer as
soon as an accurate reading has been obtained.
Take care to replace pressure tap plug.

Page 19
TABLE 12
Supply and Manifold Pressure Settings at all Altitudes
Model
Input Size Gas 0-4500 ft 4501-7500 ft 7501 - 10,000 ft
Supply Pressure
in.wg.
Min Max
045 Nat 3.5 3.5 3.5 4.5 13.0
LP/propane 10.0 10.0 10.0 11.0 13.0
070 Nat 3.5 3.3 3.5 4.5 13.0
LP/propane 10.0 10.0 10.0 11.0 13.0
090 Nat 3.5 3.3 3.5 4.5 13.0
LP/propane 10.0 10.0 10.0 11.0 13.0
110 Nat 3.5 3.3 3.5 4.5 13.0
LP/propane 10.0 10.0 10.0 11.0 13.0
TABLE 13
Pressure Switch and Gas Conversion Kits at all Altitudes
Model
Input Size
High Altitude Pressure Switch Kit
High Altitude
Natural Gas Burner
Orifice Kit
Natural Gas to LP/Propane
Burner Orifice Kit
LP/Propane to
Natural Gas Burner
Orifice Kit
0-4500 ft 4501-7500 ft 7501 - 10,000 ft 7501 - 10,000 ft 0 - 7500 ft 7501 - 10,000 ft 0 - 7500 ft
045
No Change
No Change
80W51 73W37 11K49 11K44 73W81
070 80W52
090 No Change
110 80W52
NOTE - A natural to LP./Propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion
procedure.

Page 20
H- Proper Ground and Voltage
A poorly grounded furnace can contribute to premature ig
nitor failure. Use the following procedure to check for
ground and voltage to the integrated control.
1 - Measure the AC voltage between Line Neutral (spade
terminals) and “C” terminal (low voltage terminal
block) on the integrated control. See figure 20. A wide
variation in the voltage between Line Neutral and “C”
as a function of load indicates a poor or partial ground.
Compare the readings to the table below. If the read
ings exceed the maximum shown in table 1, make re
pairs before operating the furnace.
2 - In addition, measure the AC voltage from Line Hot to
Line Neutral (spade terminals) on the integrated con
trol. See figure 21. This voltage should be in the range
of 97 to 132 Vac
TABLE 14
Furnace Status Measurement VAC
Expected Maximum
Power On Furnace Idle 0.3 2
CAI / Ignitor Energized 0.75 5
Indoor Blower Energized Less than 2 10
CHECK VOLTAGE BETWEEN LINE NEUTRAL
AND LOW VOLTAGE “C” TERMINAL
FIGURE 20
CHECK VOLTAGE BETWEEN LINE HOT
AND LINE NEUTRAL
FIGURE 21
V-TYPICAL OPERATING CHARACTERISTICS
A-Blower Operation and Adjustment
NOTE- The following is a generalized procedure and
does not apply to all thermostat controls.
1 - Blower operation is dependent on thermostat control
system.
2 - Generally, blower operation is set at thermostat sub
base fan switch. With fan switch in ON position, blower
operates continuously. With fan switch in AUTO position,
blower cycles with demand or runs continuously while
heating or cooling circuit cycles.
3 - Depending on the type of indoor thermostat, blower
and entire unit will be off when the system switch is in
OFF position.
B-Temperature Rise (Figure 22)
Temperature rise for EL180DFE units depends on unit in
put, blower speed, blower horsepower and static pressure
as marked on the unit rating plate. The blower speed must
be set for unit operation within the range of “TEMP. RISE
°F” listed on the unit rating plate.