Lennox EL180UHE SERIES User manual

Page 1 ©2013 Lennox Industries Inc.
EL180UHE(X)
Service Literature
Corp. 1302-L1
Revised 06-2013
EL180UHE(X) series units are mid-efficiency gas furnaces
used for upflow or horizontal applications only, manufac
tured with Lennox Duraloktheat exchangers formed of
aluminized steel. EL180UHE(X) units are available in heat
ing capacities of 44,000 to 132,000 Btuh and cooling ap
plications 2 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.
EL180UHE(X) model units are equipped with a hot surface
ignition system. The EL180UHE(X) unit meets the Califor
nia Nitrogen Oxides (NOx) Standards and California Sea
sonal Efficiency requirements. 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.
TABLE OF CONTENTS
Specifications Page 2.............................
Blower Data Page 4..............................
Parts Identification Page 6.........................
I Unit Components Page 7........................
II Installation Page 20.............................
III Start Up Page 20..............................
IV Heating System Service Checks Page 20.........
V Typical Operating Characteristics Page 25.........
VI Maintenance Page 25..........................
VII Wiring and Sequence of Operation Page 28......
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.
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
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.

Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model No. EL180UH045E36A EL180UH070E36B EL180UH090E48B
ELModel No. - Low Nox EL180UH045XE36A EL180UH070XE36B 180UH090XE48B
1AFUE 80% 80% 80%
Input - Btuh 44,000 66,000 88,000
Output - Btuh 35,200 52,800 70,400
Temperature rise range - °F 15 - 45 40 - 70 35 - 65
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
High Static - in. w.g. 0.50 0.50 0.50
Connections
in.
Flue connection - in. round 4 4 4
Gas pipe size IPS 1/2 1/2 1/2
Indoor
Blower
Wheel nom. dia. x width - in. 10 x 8 10 x 10 10 x 10
Motor output - hp 1/2 1/2 3/4
Tons of add-on cooling 1.5 - 3 1.5 - 3 2.5 - 4
Air Volume Range - cfm 350 - 1380 345 - 1330 750 - 1785
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 6.8 6.8 8.4
Maximum overcurrent protection 12 12 12
Shipping Data lbs. - 1 package 111 127 142
SPECIFICATIONS
Gas
Heating
Performance
Model No. EL180UH090E60C EL180UH110E60C EL180UH135E60D
Model No. - Low Nox - - - EL180UH110XE60C - - -
1AFUE 80% 80% 80%
Input - Btuh 88,000 110,000 132,000
Output - Btuh 70,400 88,000 105,600
Temperature rise range - °F 30 - 60 35 - 65 30 - 60
Gas Manifold Pressure (in. w.g.)
Nat. Gas / LPG/Propane
3.5 / 10.0 3.5 / 10.0 3.5 / 10.0
High Static - in. w.g. 0.50 0.50 0.50
Connections
in.
Flue connection - in. round 4 4 4
Gas pipe size IPS 1/2 1/2 1/2
Indoor
Blower
Wheel nom. dia. x width - in. 11-1/2 x 10 11-1/2 x 10 11 x 11
Motor output - hp 1 1 1
Tons of add-on cooling 3 - 5 3 - 5 3.5 - 5
Air Volume Range - cfm 990 - 2290 920 - 2315 1140 - 2495
Electrical
Data
Voltage 120 volts - 60 hertz - 1 phase
Blower motor full load amps 10.9 10.9 10.9
Maximum overcurrent protection 12 12 12
Shipping Data lbs. - 1 package 152 160 178
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.
UPFLOW POSITION
Vent Type Type B1 Type C
Sides 0 (0) 10 (0)
Rear 0 (0) 0 (0)
Top 1 (25) 1 (25)
Front 2-1/4 (57) 2-1/4 (57)
Front (service/alcove) 24 (610) 24 (610)
Floor Combustible Combustible
Flue 1 (25) 6 (152)
NOTE − Air for combustion must conform to the methods outlined in the National
Fuel Gas Code (NFPA 54/ANSI-Z223.1).
NOTE − In the U.S. ue sizing must conform to the methods outlined in the
current National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or applicable
provisions of local building codes.
1Left side requires 4 in. if single wall vent is used on 14-1/2 in. cabinets, 2 in. on
17-1/2 in. cabinets.
INSTALLATION CLEARANCES - INCHES (MM)
HORIZONTAL POSITION
Vent Type Type B1 Type C
End 12 12
Rear 0 (0) 0 (0)
Top 10 (0) 10 (0)
Front 2-1/4 (57) 2-1/4 (57)
Front (service) 24 (610) 24 (610)
Floor Combustible Combustible
Flue 1 (25) 6 (152)
NOTE − Air for combustion must conform to the methods outlined in the National
Fuel Gas Code (NFPA 54/ANSI-Z223.1).
NOTE − In the U.S. ue sizing must conform to the methods outlined in the
current National Fuel Gas Code (NFPA 54/ANSI-Z223.1) or applicable
provisions of local building codes.
1Line contact installation permissible between jacket top or sides and building
joists.

Page 3
OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA
“A” Width
Models
“B” Width
Models
“C” Width
Models
“D” Width
Models
CABINET ACCESSORIES
Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 51W10
Return Air Base - Upow only 65W75 50W98 50W99 51W00
FILTERS
1Air Filter and Rack Kit Horizontal (end) 87L95 87L96 87L97 87L98
Size of lter - in. 14 x 25 x 1 18 x 25 x 1 20 x 25 x 1 25 x 25 x 1
Side Return Single 44J22 44J22 44J22 44J22
Ten Pack 66K63 66K63 66K63 66K63
Size of lter - in. 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1
NIGHT SERVICE KITS
Night Service Kit 84W47 84W47 84W47 84W47
Safety Service Kit 89W19 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 80W52 80W51 70W89 76W15 73W81 73W37
070 No Change 80W52 80W51 70W89 76W15 73W81 73W37
090 No Change 80W52 80W51 70W89 76W15 73W81 73W37
110 No Change 80W57 80W52 70W89 76W15 73W81 73W37
135 No Change 80W52 80W51 70W89 76W15 73W81 73W37
HIGH ALTITUDE DERATE
NOTE - Units may be installed at altitudes up to 2000 ft. above sea level without any modications.
At altitudes above 2000 ft. units must be derated to match information in the shaded areas shown below.
NOTE - This is the only permissible derate for these units.
Input
Gas Manifold Pressure (Outlet) in. w.g. Line Pressure - in. w.g.
0 - 2000 Feet 2001 - 4500 Feet 4501 - 7500 Feet 7501 - 10,000 ft. Minimum
Maximum
Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
1Natural
Gas
LPG/
Propane
Natural
Gas
LPG/
Propane
045 3.5 10 3.2 10 3 10 3.5 10 4.5 11 13
070 3.5 10 3.2 10 2.8 10 3.5 10 4.5 11 13
090 3.5 10 3.2 10 2.7 9.6 3.5 10 4.5 11 13
110 3.5 10 3.5 10 3 9.6 3.5 10 4.5 11 13
135 3.5 10 3.5 10 2.9 9.6 3.5 10 4.5 11 13
1 Natural Gas High Altitude Orice Kit required.

Page 4
BLOWER DATA
EL180UH045E36A 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 1380 265 1155 165 995 120 975 115 945 105
0.10 1345 270 1120 175 950 120 880 105 865 100
0.20 1320 285 1080 190 900 125 805 105 700 85
0.30 1290 295 1055 200 875 135 750 110 640 90
0.40 1265 310 1010 205 825 145 710 120 595 95
0.50 1230 315 990 215 790 155 660 125 535 100
0.60 1190 330 945 230 750 165 630 135 500 110
0.70 1165 340 915 235 705 170 570 140 435 115
0.80 1130 350 880 245 670 180 535 150 380 120
EL180UH070E36B 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 1415 265 1330 170 1215 135 1175 125 1075 85
0.10 1415 280 1295 170 1145 145 1130 130 955 95
0.20 1355 290 1225 185 1110 150 1080 140 885 100
0.30 1330 300 1190 200 1060 160 1035 155 825 110
0.40 1290 310 1155 205 1015 175 970 160 770 120
0.50 1245 325 1115 215 980 180 930 170 695 125
0.60 1225 335 1045 230 920 190 865 180 625 135
0.70 1190 350 1000 235 855 205 790 190 540 140
0.80 1160 365 925 245 790 205 735 200 445 145
EL180UH090E48B 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 1785 380 1570 270 1440 220 1395 190 1190 120
0.10 1755 395 1535 275 1420 230 1350 205 1140 130
0.20 1730 415 1505 290 1380 245 1310 215 1110 145
0.30 1690 435 1460 305 1345 260 1275 230 1065 155
0.40 1645 440 1435 320 1310 270 1240 240 1010 165
0.50 1615 455 1395 335 1265 285 1180 255 955 180
0.60 1590 470 1350 350 1210 290 1150 265 915 185
0.70 1545 475 1300 360 1175 305 1095 275 860 200
0.80 N/A N/A 1270 370 1140 310 1040 285 820 210

Page 5
BLOWER DATA
EL180UH110E60C PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2230 635 1945 430 1715 295 1555 230 1470 185 2315 645 1990 415 1780 300 1610 230 1510 200
0.10 2180 655 1905 445 1690 305 1510 240 1340 175 2260 655 1945 425 1740 315 1550 240 1400 185
0.20 2135 680 1865 465 1630 330 1470 260 1280 190 2210 680 1895 450 1680 335 1510 255 1350 200
0.30 2090 695 1830 480 1595 345 1440 275 1235 200 2165 700 1850 465 1650 355 1455 275 1285 210
0.40 2050 715 1785 495 1550 360 1385 285 1175 210 2130 715 1830 485 1585 365 1395 285 1230 225
0.50 2025 730 1740 520 1500 375 1340 300 1130 225 2095 730 1770 500 1535 385 1365 300 1175 235
0.60 2010 750 1710 535 1470 390 1305 320 1080 240 2055 755 1725 515 1495 400 1305 315 1135 250
0.70 1965 755 1670 555 1420 410 1255 330 1015 255 2000 765 1675 535 1465 410 1255 325 1080 265
0.80 1905 785 1635 560 1380 425 1215 350 975 270 1965 785 1640 555 1400 425 1210 345 1025 275
EL180UH090E60C PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2255 640 1940 420 1750 310 1580 230 1485 185 2290 655 1980 425 1775 310 1605 235 1495 195
0.10 2200 655 1910 440 1705 315 1535 240 1385 190 2250 675 1945 445 1730 320 1555 245 1400 190
0.20 2150 675 1865 450 1655 340 1490 260 1340 205 2210 695 1885 465 1680 340 1510 265 1350 205
0.30 2125 695 1835 475 1635 355 1450 275 1285 215 2165 715 1850 475 1645 355 1470 275 1285 215
0.40 2090 715 1800 495 1585 370 1405 285 1235 230 2135 720 1810 490 1595 370 1410 290 1225 230
0.50 2060 735 1760 510 1545 385 1370 305 1200 245 2070 735 1765 515 1545 390 1370 305 1180 245
0.60 2020 750 1725 525 1515 405 1320 320 1145 255 2030 760 1715 530 1495 405 1325 320 1140 255
0.70 1980 765 1680 540 1465 420 1265 330 1105 270 1990 775 1685 540 1450 425 1265 330 1095 270
0.80 1935 785 1635 560 1420 435 1225 350 1055 285 1950 795 1645 560 1415 435 1225 345 1040 285
EL180UH135E60D PERFORMANCE (Less Filter)
External
Static
Pressure
in. w.g.
Air Volume / Watts at Different Blower Speeds
Bottom Return Air, Side Return Air with Optional Return
Air Base, Return Air from Both Sides or Return Air from
Bottom and One Side.
Single Side Return Air − Air volumes in bold require eld
fabricated transition to accommodate 20 x 25 x 1 in. air lter
in order to maintain proper air velocity.
High Med-High Medium Med-Low Low High Med-High Medium Med-Low Low
cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts
0.00 2495 755 2295 590 2045 435 1845 315 1650 230 2365 725 2295 575 2005 410 1820 300 1635 235
0.10 2440 780 2220 620 2015 445 1820 330 1615 245 2350 745 2210 595 2000 435 1745 320 1530 230
0.20 2390 790 2175 640 1935 470 1735 350 1550 255 2330 775 2175 625 1945 455 1730 330 1490 250
0.30 2360 805 2140 655 1895 490 1720 370 1485 275 2245 785 2135 645 1895 475 1655 355 1425 265
0.40 2285 835 2125 675 1850 510 1660 380 1455 290 2215 810 2085 660 1840 495 1600 375 1385 285
0.50 2240 860 2060 690 1815 535 1610 400 1415 310 2175 825 2045 680 1815 505 1590 390 1340 290
0.60 2225 865 2015 715 1785 550 1535 420 1330 320 2125 845 1995 700 1765 530 1525 405 1300 310
0.70 2160 895 1955 735 1755 570 1500 440 1265 340 2095 865 1950 710 1700 545 1485 420 1260 325
0.80 2105 905 1925 750 1715 580 1435 450 1215 345 2065 880 1890 725 1680 565 1415 445 1205 345

Page 6
FIGURE 1
Control Box
(includes integrated control,
interlock switch and transformer)
Gas Valve
Burner Box
(includes sensor, ignitor
and rollout switches)
Combustion Air Inducer
Combustion Air Inducer
Pressure Switch
Heat Exchanger
Primary Limit
(under
combustion
air inducer)
Make-Up Box
Blower Assembly
Power Choke
(4 and 5 Ton Only)
PARTS ARRANGEMENT
Access Panel

Page 7
I-UNIT COMPONENTS
EL180UHE(X) unit components are shown in figure 1.The
gas valve, combustion air inducer and burners can be ac
cessed by removing the upper access panel. Electrical
components are in the control box (figure 2) found in the
blower section.
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.
NOTE - The door interlock switch is a safety switch. Do not
by-pass or jumper switch.
FIGURE 2
CONTROL BOX EL180UHE(X)
DOOR INTERLOCK
SWITCH (S51)
INTEGRATED IGNITION
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 designations
in tables 1, 2 and 3), sensor and ignitor (figure 6). The inte
grated control and ignitor work in combination to ensure
furnace ignition and ignitor durability. The integrated con
trol, controls all major furnace operations. The integrated
control also features a RED LED for troubleshooting and
two accessory terminals rated at (1) one amp. See table 4
for troubleshooting diagnostic codes. The nitride ignitor is
made from a non-porous, high strength proprietary ceram
ic material that provides long life and trouble free mainte
nance.
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 8
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 9
TABLE 4
The integrated control is equipped with an LED light for troubleshooting. The diagnostic codes are listed below in table 4.
RED LED
Flash Code Diagnostic Codes / Status of Furnace
Off No power to control or board fault detected
On 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 min
utes
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.
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉ
ÉÉ
DEMAND
CAI
GAS VALVE
15
ON
OFF
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉÉ
ÉÉ
38
ÉÉÉÉÉÉÉÉÉÉ
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

Page 10
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 11
EL180UHE HEATING COMPONENTS
FIGURE 6
Gaskets
Collector Box
Orifice Plate
Flue Transition
Pressure Switch
Combustion Air Inducer
Manifold And Gas Valve
Ignitor
Rollout Switches
(-090, -110 -135 units)
Sensor
Rollout Switches
(-045 and -070 units)
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 manual
ly reset a tripped switch, push the reset button located on
the control.
6. Primary Limit Control
The primary limit on EL180UHE(X) units is located in the
heating vestibule panel under the combustion air inducer.
See figure 7. When excess heat is sensed in the heat ex
changer, the limit will open. If the limit is open, the inte
grated control energizes the supply air blower and closes
the gas valve. The limit automatically resets when unit tem
perature returns to normal. The switch must reset within
three minutes or SureLight®control will go into Watch
guard 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 Dave
Net®.
FIGURE 7
Primary Limit Under Combustion Air Inducer
Primary
Limit
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 with
steel wool) without removing any part of the burners. Dur
ing operation, flame is sensed by current passed through
the flame and sensing electrode. The integrated control al
lows the gas valve to remain open as long as flame signal is
sensed.

Page 12
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.
To Measure Flame Signal - Integrated Control:
Use a digital readout meter capable of reading DC micro
amps. See figure 8 and table 5 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 5
Flame Signal in Microamps
Normal Low Drop Out
1.5 0.5 - 1.4 0.4
FIGURE 8
Measuring Flame Signal
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 13
8. Gas Valve (Figure 6)
The EL180UHE(X) uses an internally redundant gas valve
to assure 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 integrated control. 24V applied to the terminals
energizes the valve.
Inlet and outlet pressure taps are located on the valve. A
regulator adjustment screw is located on the valve.
LPG changeover kits are available from Lennox. Kits in
clude burner orifices and a gas valve regulator spring.
9. Combustion Air Inducer (B6)
All EL180UHE(X) 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 con
trolled by integrated control A92. The inducer also oper
ates for 15 seconds before burner ignition (pre‐purge) and
for 5 seconds after the gas valve closes (post‐purge).
A pressure switch mounted on the combustion air inducer
orifice plate is used to prove inducer operation. The com
bustion air inducer orifice will be different for each model.
See table 6 for orifice sizes. The switch monitors air pres
sure in the inducer housing. During normal operation, the
pressure in the housing is negative. If pressure becomes
less negative (signifying any obstruction in the flue) the
pressure switch opens. When the pressure switch opens,
the integrated control (A92) immediately de-energizes the
gas valve to prevent burner operation.
TABLE 6
EL180UHE(X) Unit C.A.I. Orifice Size
045E36A 1.063”
070E36B 1.316”
090E48B, 090E60C 1.531”
110E60C 1.690”
135E60D 1.940”
10. Ignitor (Figure 6)
The nitride ignitor used on EL180UHE 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 9 for resistance, and voltage check.
NOTE - The EL180UHE(X) furnace contains electronic
components that are polarity sensitive. Make sure that the
furnace is wired correctly and is properly grounded.

Page 14
FIGURE 9
Test 2
Check ignitor for correct resistance.
Separate 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.
Meter
(set to ohms)
Meter
Integrated Control Board
Detail
Meter
(set to ohms)
Test 1
Check ignitor circuit for correct resistance.
Remove 4-pin plug from control.
Check ohms reading across terminals 2 and 4.
The reading should be between 39 and 70 ohms. If
value is correct, this is the only test needed.
If the reading on the meter is not correct, (0 or infinity)
then a second test is needed.
IGNITOR CHECKS
(set to ac volts)

Page 15
11. Combustion Air Inducer
Pressure Switch (S18)
EL180UHE(X) series units are equipped with a combustion
air pressure switch located on the combustion air inducer
orifice bracket. The switch is connected to the combustion
air inducer housing by means of a flexible silicone hose. It
monitors negative air pressure in the combustion air induc
er housing.
The switch is a single‐pole single‐throw proving switch
electrically connected to the furnace control. The purpose
of the switch is to prevent burner operation if the combus
tion air inducer is not operating or if the flue becomes ob
structed.
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 7. 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 7
EL180UHE(X) inches w.c.
Make Break +0.05
045E36A -0.75 -0.65
070E36B -0.83 -0.68
090E48B, 090E60C -0.80 -0.65
110E60C -0.83 -0.68
135E60D -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 10 for measuring operating pressure and check
ing resistance in the pressure switch.
FIGURE 10
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 16
Multiple Venting
The EL180UHE(X) furnace can vent in multiple positions.
See figure 11.
The make up box may be removed and the combustion air
inducer may be rotated clockwise or counterclockwise 90°
to allow for vertical or horizontal vent discharge in a vertical
or horizontal cabinet position. Remove the four mounting
screws, rotate the assembly (assembly consists of orifice
plate, proving switch, gasket and combustion air inducer),
then reinstall the mounting screws. See unit Installation In
structions for more detail.
IMPORTANT
The combustion air pressure switch must be moved
for horizontal discharge air left position.
FIGURE 11
vent pipe
vent pipe
flue
transition
vent pipe
FLOW
AIR
flue transition
vent pipe
pressure switch
vent pipe
In all positions route the wires away from moving parts and the heat of the inducer
motor to prevent damage to the wires. The pressure switch must be installed above
the CAI to prevent moisture from collecting in the hoses or switch.
FLOW
AIR
Collector Box
Vent Pipe
Pressure
Switch
vent pipe
Collector Box
FLOW
AIR
Pressure
Switch

Page 17
12. Blower Motor
IMPORTANT
Each blower is statically and dynamically bal
anced as an assembly before installation in the
unit.
EL180UHE 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
motor is programmed to provide constant torque at each of
the five selectable speed taps. Each tap requires 24 volts to
energize.
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 fig
ure 14 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
centered in the blower housing as shown in figure 12.
When replacing the indoor blower motor the set screw
must be aligned and tightened with the motor shaft as
shown in figure 13.
FIGURE 12
Center Blower Wheel
in Blower Housing
BLOWER WHEEL REPLACEMENT
FIGURE 13
Set Screw
Housing Hub
ALIGN AND TIGHTEN SET SCREW WITH
FLAT SIDE OF MOTOR SHAFT
Motor
Shaft

Page 18
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 upstream
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−Mete
r
(set to VAC
)
120 120
24
Multi−Mete
r
(set to VAC
)
Check for 24 volts across terminals “24 COM” and “FAN” termi
nals 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
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 14

12
3
4
5
6
7
8
9
10
11 12
1/16
TURN
Page 19
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 15.
TWO HARNESS
CONNECTIONS
MOTOR CONTROL MODULE
MOTOR
FIGURE 15
Unplug the Two Harness Connection
4. Remove the two hex head bolts securing the motor
control module to the motor (see figure 16).
REMOVE BOTH HEX
HEAD BOLTS
FIGURE 16
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 (Figure17)
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 17
Motor Test
TABLE 8
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 16. 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 (figure18). 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 18
Drip Loop

Page 20
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.
EL180UHE(X) units are equipped with a hot surface
ignition system. Do not attempt to light manually.
Gas Valve Operation
FIGURE 19
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 upper access panel.
6 - Move gas valve switch to OFF position. Do not force.
See figure 19.
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 to ON position. Do not force.
See figure 19.
9 - Replace the upper 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 upper access panel.
4 - Move gas valve switch to OFF position. Do not force.
See figure 19.
5 - Replace the upper 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 EL180UHE(X) 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 exceed 600 in-lbs (50 ft-lbs) torque when at
taching 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 0.5psig (14” W.C.). See figure 20. If
the pressure is equal to or less than 0.5psig (14”W.C.),
close the manual shut-off valve before pressure testing to
isolate furnace from gas supply.