Lenox ML180UH110AP36C, ML180UH135AP60D, ML180UH110AP60C, ML180UH070AP36A, ML180UH090AP48B Unit Information
Corp. 1218-L4
Service Literature
ML180UHA series units are mid-efficiency gas furnaces
used for upflow or horizontal applications only, manufac
tured with Lennox Duralok Plust heat exchangers formed
of aluminized steel. ML180UHA units are available in heat
ing capacities of 69.6 to 139.3 MJ/h and cooling applica
tions 10 to 17 kW. Refer to Engineering Handbook for prop
er sizing.
Units are factory equipped for use with natural gas. Kits are
available for conversion to LP/Propane operation.
ML180UHA model units are equipped with a hot surface
ignition system. All units use a redundant gas valve to as
sure safety shut-off as required.
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.
Revised 05 /2017
WARNING
This product contains a chemical known to the State
of California to cause cancer, birth defects, or other
reproductive harm.
TABLE OF CONTENTS
Specifications Page 2.............................
Blower Data Page 3..............................
Parts Identification Page 5.........................
I Unit Components Page 6........................
ML180UHA
IMPORTANT
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 qualified installer, service agency
or the gas supplier.
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.
II Installation Page 14.............................
III Start Up Page 14..............................
IV Heating System Service Checks Page 15.........
V Typical Operating Characteristics Page 19.........
VI Maintenance Page 20..........................
VII Wiring and Sequence of Operation Page 22......
Page 1
WARNING
Sharp edges.
Be careful when servicing unit to avoid sharp edges
which may result in personal injury.
WARNING
Do not modify this appliance.
© 2017 Lennox Industries Inc.
Page 2
SPECIFICATIONS
Gas
Heating
Performance
Model Number ML180UH070AP36A ML180UH090AP48B ML180UH110AP36C
Australian Gas Association
Energy Rating - Stars
3.8 3.7 3.8
Input - Mj/h 69.6 92.8 116.1
Output - kW 15.5 20.6 25.8
Temperature rise range - °C 14 - 31 14 - 31 19 - 36
Gas Manifold Pressure (kPa)
Natural Gas / Propane
0.87 / 2.30 0.87 / 2.30 0.87 / 2.30
High Static - Pa 125 125 125
Connections Flue connection - mm round 102 102 102
Gas pipe size IPS 1/2 in. 1/2 in. 1/2 in.
Indoor
Blower
Wheel nom. diameter x width - mm 254 x 203 254 x 254 254 x 254
Motor output - W 248 373 373
Add-on cooling - kW 7-10.6 7-14.1 7-14.1
Air Volume Range - L/s 282 - 716 229 - 890 239 - 827
Electrical Data Voltage 220/240 volts - 50 hertz - 1 phase (less than 10 amps)
Shipping Data kg - 1 package 54 63 70
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
SPECIFICATIONS
Gas
Heating
Performance
Model Number ML180UH110AP60C ML180UH135AP60D
Australian Gas Association
Energy Rating - Stars
3.8 3.9
Input - Mj/h 116.1 139.3
Output - kW 25.8 31.0
Temperature rise range - °C 17 - 33 17 - 33
Gas Manifold Pressure (kPa)
Natural Gas / Propane
0.87 / 2.30 0.87 / 2.30
High Static - Pa 125 125
Connections Flue connection - mm round 102 102
Gas pipe size IPS 1/2 in. 1/2 in.
Indoor
Blower
Wheel nom. diameter x width - mm 292 x 254 279 x 279
Motor output - W 746 746
Add-on cooling - kW 14.1-17.6 14.1-17.6
Air Volume Range - L/s 633 - 1138 602 - 1159
Electrical Data Voltage 220/240 volts - 50 hertz - 1 phase (less than 10 amps)
Shipping Data kg - 1 package 71 79
NOTE - Filters and provisions for mounting are not furnished and must be eld provided.
OPTIONAL ACCESSORIES - ORDER SEPARATELY
“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 - Upow only 65W75 50W98 50W99 51W00
FILTERS
1
Air Filter and Rack Kit Horizontal (end) 87L95 87L96 87L97 87L98
Size of lter - mm 356 x 635 x 25 457 x 635 x 25 508 x 635 x 25 635 x 635 x 25
Side Return Single 44J22 44J22 44J22 44J22
Ten Pack 66K63 66K63 66K63 66K63
Size of lter - mm 406 x 635 x 25 406 x 635 x 25 406 x 635 x 25 406 x 635 x 25
1
Cleanable polyurethane, frame-type lter.
Page 3
BLOWER DATA
ML180UH070AP36A PERFORMANCE (Less Filter)
External
Static
Pressure
Pa
Air Volume at Various Blower Speeds
High Medium Low
L/s Watts L/s Watts L/s Watts
0 716 771 589 615 469 468
25 687 752 564 597 435 448
50 675 724 554 583 430 441
75 662 708 547 569 421 430
100 649 691 530 554 408 417
125 633 672 517 541 393 405
150 616 650 503 524 372 387
175 595 624 488 514 359 375
200 573 608 472 494 324 363
225 551 590 447 477 307 346
250 523 561 424 454 282 331
ML180UH090AP48B PERFORMANCE (Less Filter)
External
Static
Pressure
Pa
Air Volume at Various Blower Speeds
High
Medium-
High
Medium-
Low
Low
L/s Watts L/s Watts L/s Watts L/s Watts
0 890 1085 715 892 497 598 423 493
25 849 1050 679 855 463 577 386 481
50 849 1016 679 831 460 565 384 464
75 831 967 676 807 456 546 369 447
100 827 937 667 773 452 526 364 434
125 816 906 660 747 439 509 349 421
150 799 872 647 718 426 494 331 408
175 784 845 629 691 411 477 308 394
200 754 808 601 642 394 460 290 383
225 722 765 577 622 359 435 256 363
250 674 713 555 593 332 421 229 348
ML180UH110AP36C PERFORMANCE (Less Filter)
External
Static
Pressure
Pa
Air Volume at Various Blower Speeds
High
Medium-
High
Medium-
Low
Low
L/s Watts L/s Watts L/s Watts L/s Watts
0 827 1106 660 884 460 574 404 478
25 800 1063 630 850 434 558 378 463
50 801 1043 631 819 432 541 369 451
75 779 984 631 807 434 527 359 438
100 773 962 624 777 422 512 352 422
125 773 938 620 758 408 490 335 4 11
150 761 907 609 725 382 472 331 396
175 741 854 593 695 383 460 319 386
200 722 832 580 659 366 441 299 372
225 699 777 554 638 351 432 263 354
250 677 741 527 600 331 4 11 239 340
ML180UH110AP60C PERFORMANCE (Less Filter)
External
Static
Pressure
Pa
Air Volume 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 508 x 635 x 25 mm
air lter in order to maintain proper air velocity.
High Medium Low High Medium Low
L/s Watts L/s Watts L/s Watts L/s Watts L/s Watts L/s Watts
0 1165 1447 964 1173 826 987 1126 1452 934 1172 794 984
25 1144 1408 938 1149 803 966 1104 1427 910 1150 772 964
50 1115 1389 932 1121 797 943 1085 1391 902 1126 768 943
75 1104 1358 922 1104 787 926 1071 1356 896 1110 756 925
100 1084 1333 908 1082 773 902 1059 1340 881 1079 750 907
125 1063 1303 905 1079 756 877 1037 1310 869 1064 741 890
150 1043 1274 888 1050 748 865 1020 1282 860 1041 731 872
175 1027 1249 871 1024 738 845
1005 1248 839 1022 717 852
200 1005 1224 849 994 723 815 987 1224 821 997 699 831
225 980 1179 835 974 696 800 956 1192 801 966 678 808
250 947 1140 807 943 677 775 939 1158 789 955 665 786
ML180UH135AP60D PERFORMANCE (Less Filter)
External
Static
Pressure
Pa
Air Volume 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 508 x 635 x 25 mm
air lter in order to maintain proper air velocity.
High Medium Low High Medium Low
L/s Watts L/s Watts L/s Watts L/s Watts L/s Watts L/s Watts
0 1153 1460 958 1167 810 967 1114 1469 941 1219 786 992
25 1126 1425 931 1139 788 945 1091 1440 917 1196 759 967
50 1118 1411 923 1125 773 928 1079 1411 913 1173 751 950
75 1087 1374 915 1113 765 914 1064 1402 893 1149 743 933
100 1083 1344 891 1079 752 900 1048 1375 887 1130 734 920
125 1067 1325 890 1066 741 884 1032 1345 866 1101 720 899
150 1038 1284 862 1036 731 869 1012 1322 852 1072 708 881
175 1034 1269 844 1016 712 849
994 1291 834 1053 690 860
200 1005 1239 832 995 697 824 987 1271 820 1029 663 834
225 977 1204 804 975 677 813 956 1238 797 1010 650 815
250 952 1173 789 953 640 781 936 1220 783 988 627 795
BLOWER DATA
Pressure Switch
Combustion Air Inducer
Gas Valve
Burner/Manifold Assembly
ML180UHA PARTS ARRANGEMENT
Heat Exchanger
Blower Access Panel
Upper Access Panel
Control Box
Capacitor
Transformer
Limit Switch
IEC Receptacle
(under combustion air inducer)
Blower Assembly
Shipping Pad
ML180UH090AP48B, & ML180UH110AP36C only.
(
Remove prior to operation
)
FIGURE 1
Page 5
I-UNIT COMPONENTS
ML180UHA 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.
3. Circuit Breaker (CB8)
A 24V circuit breaker is also located in the control box.
The switch provides overcurrent protection to the trans
former (T1). The breaker is rated 3A at 32V. If the current
exceeds this limit the breaker will trip and all unit opera
tion will shutdown. The breaker can be manually reset
by pressing the button on the face. See figure 3.
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 230V primary and a 24V sec
ondary.
2. Door Interlock Switch (S51)
A door interlock switch rated 14A at 230VAC is wired in se
ries with line voltage. When the blower door is removed the
unit will shut down.
CONTROL BOX ML180UHA
Door Interlock Switch
Integrated Control
FIGURE 2
CIRCUIT BREAKER CB8
PRESS TO RESET
FIGURE 3
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 4 with control terminal designa
tions in tables 1 and 2.) sensor and ignitor (figure 6). The
integrated control and ignitor work in combination to en
sure furnace ignition and ignitor durability. The integrated
control, controls all major furnace operations. The inte
grated control also features one LED light (AN1 red) for
troubleshooting and two accessory terminals rated at (1)
one amp. The integrated control also features a (3) amp
fuse for overcurrent protection. See table 3 for trouble
shooting diagnostic codes. The nitride ignitor is made
from a non-porous, high strength proprietary ceramic ma
terial that provides long life and trouble free maintenance.
The integrated control continuously monitors line voltage
and maintains the ignitor power at a consistent level to
provide proper lighting and maximum ignitor life.
Page 6
LED
(red)
INTEGRATED CONTROL
TERMINAL DESIGNATIONS
HUM - Humidifier 230VAC
LINE - Input 230VAC
XFMR - Transformer 230VAC
EAC - Electronic Air Cleaner 230VAC
COOL - Cool Speed 230VAC
PARK1, PARK2 - Dead terminals for alternate speed taps
NEUTRALS - Neutral terminals 230VAC
HEAT - Heating Speed 230VAC
FS - Flame Sense
TABLE 1
5-Pin Terminal Designation
PIN # FUNCTION
1 Ignitor Line
2
3
4
5
Not Used
Combustion Air Inducer Low
Combustion Air Inducer Neutral
Ignitor Neutral
FIGURE 4
TABLE 2
12-Pin Terminal Designations
PIN # FUNCTION
1 Not Used
2 Not Used
3 Rollout Switch Input
4 Ground
5 TH 24V Hot
6 High Limit Input
7 Gas Valve Line
8 Gas Valve Common
9 TR 24V Return
10 Ground
11 Rollout Switch Output
12 Pressure Switch
Page 7
TABLE 3
FLASH CODE
(X + Y)
STATUS / ERROR DESCRIPTION
FLASH CODE DESCRIPTIONS
Pulse A 1/4 second flash followed by four seconds of off time.
Heartbeat Constant 1/2 second bright and 1/2 second dim cycles.
X + Y
Pulse Power on - Standby.
Heartbeat Normal operation - signaled when heating demand initiated at thermostat.
LED flashes X times at 2Hz, remains off for two seconds, flashes Y times at 2Hz, remains off for four
seconds, then repeats.
FLAME CODES
1 + 2 Low flame current -- check flame sensor.
1 + 3 Flame sensed out of sequence -- flame still present. Flame sensed without gas valve energized.
PRESSURE SWITCH CODES
2 + 3 Low pressure switch failed open. Check blocked inlet/exhaust .
2 + 4 Low pressure switch failed closed. Pressure switch closed prior to activation of combusiton air inducer.
LIMIT CODE
3 + 1 Limit switch open.
WATCHGUARD CODES
4 + 1 Watchguard -- Exceeded maximum number of retries. Burners failed to light.
4 + 2 Watchguard -- Exceeded maximum number of retries or last retry was due to pressure switch opening.
4 + 3 Watchguard -- Exceeded maximum number of retries or last retry was due to flame failure.
4 + 5 Watchguard -- Limit remained open longer than three minutes.
4 + 6 Watchguard -- Flame sensed out of sequence; flame signal gone.
4 + 8 Low line voltage.
HARD LOCKOUT CODES
5 + 1 Hard lockout -- Rollout circuit open or previously opened.
5 + 4
5 + 5 Gas valve fault ( sensed open when should be closed, or sensed closed when should be open).
5 + 6 Program memory fault (internal microprocessor memory fault)
5 + 7 Flame sense circuit fault. (flame sense circuit or bad flame probe fault).
5 + 8 No communication packet fault (loss of communications between redundant microprocessor fault).
5 + 9 Bad communication packet fault. (corrupted communications between redundant microprocessor fault).
5 + 10 Redundant variable fault. (internal microprocessor memory retention fault).
Reversed line voltage polarity (control will restart if the error recovers). And or no Earth groas valve
faulund
Page 8
Electronic Ignition
On a call for heat the integrated control monitors the com
bustion air inducer pressure switch. The control board will
not begin 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.
The integrated control has an added feature of ignitor pow
er regulation to maintain consistent lighting and longer igni
tor life under all line voltage conditions.
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 60 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 32° C - 43° C (90° F - 110° F) at the instant the
blower is de-energized. (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
NO JUMPER
To adjust fan-off timing, reposition jumper across pins to
60 Second
off Time
60
90
120
180
achieve desired setting.
90 Second
off Time
60
90
120
180
120 Second
off Time
60
90
120
180
180 Second
off Time
60
90
120
180
FIGURE 5
Page 9
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