Lennox ML193UH045P36B, ML193UH090P36C, ML193UH070P36B, ML193UH110P48C, ML193UH110P60C Unit Information

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Corp. 1025−L5

Service Literature

ML193UH SERIES UNITS

ML193UH series units are high−efficiency gas furnaces manufactured with Lennox DuralokPlust aluminized steel clamshell−type heat exchangers, with a stainless steel condensing coil. ML193UH units are available in heating input capacities of 44,000 to 132,000 Btuh (13 to 38.6 kW) and cooling applications from 2 through 5 tons (7.0 through

17.6 kW). Refer to Engineering Handbook for proper sizing.

Units are factory equipped for use with natural gas. A kit is available for conversion to LPG operation. All ML193UH units are equipped with a hot surface ignition system. The gas valve is redundant to assure safety shut−off as required by C.S.A.

The heat exchanger, burners and manifold assembly can be removed for inspection and service. The maintenance section gives a detailed description on how this is done.

All specifications are subject to change. Procedures outlined in this manual are presented as a recommendation only and do not supersede or replace local or state codes.

ML193UH

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 disconnect switch(es). Unit may have multiple power supplies.

Table of Contents

Specifications 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Optional Accessories 3. . . . . . . . . . . . . . . . . . . . . . . . . .

Blower Performance Data 4. . . . . . . . . . . . . . . . . . . . . .

I−Unit Components 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

II Placement and Installation 14. . . . . . . . . . . . . . . . . . . .

III−Start−Up 35. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

IV−Heating System Service Checks 36. . . . . . . . . . . . . .

V−Typical Operating Conditions 38. . . . . . . . . . . . . . . . . .

VI−Maintenance 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VII−Sequence of Operation and Flow Charts 41. . . . . . .

VIII−Integrated Control Troubleshooting 46. . . . . . . . . . .

WARNING

Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a licensed professional installer (or equivalent), service agency or the gas supplier.

WARNING

Sharp edges. Be careful when servicing unit to avoid sharp edges which may result in personal injury.

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Litho U.S.A.

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SPECIFICATIONS

Gas Heating Performance

Temperature rise range - °F 25 - 55 50 - 80 40 - 70 50 - 80

Gas Manifold Pressure (in. w.g.)

Nat. Gas / LPG/Propane

High static - in. w.g. 0.50 0.50 0.50 0.50

Connections

Intake / Exhaust Pipe (PVC) 2 / 2 2 / 2 2 / 2 2 / 2

in.

Condensate Drain Trap (PVC pipe) - i.d. 1/2 1/2 1/2 1/2

with eld supplied (PVC coupling) - o.d. 3/4 3/4 3/4 3/4

Indoor

Wheel nom. dia. x width - in. 10 x 8 10 x 8 10 x 8 10 x 8

Blower

Tons of add-on cooling 2.5 - 3 1.5 - 2 2.5 - 3 2 - 3

Air Volume Range - cfm 700 - 1600 390 - 1140 660 - 1615 695 - 1620

Electrical Data

Blower motor full load amps 6.1 3.1 6.1 6.1

Maximum overcurrent protection 15 15 15 15

Shipping Data lbs. - 1 package 122 125 127 143

NOTE - Filters and provisions for mounting are not furnished and must be eld provided.

Annual Fuel Utilization Efciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized

furnaces.

Model No. ML193UH045P36B ML193UH070P24B ML193UH070P36B ML193UH090P36C

AFUE 93% 93% 93% 93%

Input - Btuh 44,000 66,000 66,000 88,000

Output - Btuh 42,000 62,000 62,000 83,000

3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0

Gas pipe size IPS 1/2 1/2 1/2 1/2

Motor output - hp 1/3 1/5 1/3 1/3

Voltage 120 volts - 60 hertz - 1 phase

SPECIFICATIONS

Gas Heating Performance

Temperature rise range - °F 40 - 70 50 - 80 40 - 70 45 - 75

Gas Manifold Pressure (in. w.g.)

Nat. Gas / LPG/Propane

High static - in. w.g. 0.50 0.50 0.50 0.50

Connections

Intake / Exhaust Pipe (PVC) 2 / 2 2 / 2 2 / 2 2 / 2

in.

Condensate Drain Trap (PVC pipe) - i.d. 1/2 1/2 1/2 1/2

with eld supplied (PVC coupling) - o.d. 3/4 3/4 3/4 3/4

Indoor

Wheel nom. dia. x width - in. 10 x 10 10 x 10 11 ½ x 10 11 ½ x 10

Blower

Tons of add-on cooling 3 - 4 3 - 4 4 - 5 4 - 5

Air Volume Range - cfm 900 - 2025 850 - 2030 1210 - 2525 1340 - 2800

Electrical Data

Blower motor full load amps 8.2 8.2 11.5 11.5

Maximum overcurrent protection 15 15 15 15

Shipping Data lbs. - 1 package 146 155 161 178

NOTE - Filters and provisions for mounting are not furnished and must be eld provided.

Annual Fuel Utilization Efciency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized

furnaces.

Model No. ML193UH090P48C ML193UH110P48C ML193UH110P60C ML193UH135P60D

AFUE 93% 93% 93% 93%

Input - Btuh 88,000 110,000 110,000 132,000

Output - Btuh 83,000 103,000 103,000 123,000

3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0

Gas pipe size IPS 1/2 1/2 1/2 1/2

Motor output - hp 1/2 1/2 1 1

Voltage 120 volts - 60 hertz - 1 phase

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OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA

“B” Width

Models

CABINET ACCESSORIES

Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10 Return Air Base - Upow only 50W98 50W99 51W00

CONDENSATE DRAIN KITS

Condensate Drain Heat Cable 6 ft. 26K68 26K68 26K68

24 ft. 26K69 26K69 26K69 50 ft. 26K70 26K70 26K70

Heat Cable Tape Fiberglass - 1/2 in. x 66 ft. 36G53 36G53 36G53

Aluminum foil - 2 in. x 60 ft. 16P89 16P89 16P89

Crawl Space Vent Drain Kit 51W18 51W18 51W18

CONTROLS

Twinning Kit 65W80 65W80 65W80

FILTER KITS

Air Filter and

Rack Kit

Horizontal (end) Size of lter - in. 87L96 - 18 x 25 x 1 87L97 - 20 x 25 x 1 87L98 - 25 x 25 x 1

Side Return Single 44J22 44J22 44J22

Ten Pack 66K63 66K63 66K63

Size of lter - in. 16 x 25 x 1 16 x 25 x 1 16 x 25 x 1

NIGHT SERVICE KITS

Night Service Kit 51W03 51W03 51W03

TERMINATION KITS

See Installation Instructions for specic venting information.

Termination Kits Direct Vent Applications Only

Termination Kits Direct or NonDirect vent Roof Termination Flashing Kit - Direct or

Non-Direct Vent (2 ashings)

Cleanable polyurethane frame type lter.

Kits contain enough parts for two, non−direct vent installations.

Non−direct vent only.

NOTE - Termination Kits 44W92, 44W93, 30G28, 81J20 are certied to ULC S636 standard for use in Canada only.

Concentric US - 2 in. 71M80 69M29 - - -

3 in. - - - 60L46 60L46

Canada - 2 in. 44W92 44W92 - - -

3 in. - - - 44W93 44W93

Flush-Mount 2, 2-1/2 or 3 in. 51W11 51W11 51W11

Wall - Close

Couple

Wall - Close

Couple WTK

US - 2 in. 22G44 - - - - - -

3 in. 44J40 44J40 44J40

Canada - 2 in. 30G28 - - - - - -

3 in. 81J20 81J20 81J20

Roof 2 in. 15F75 15F75 - - -

Wall Ring Kit 2 in. 15F74

2 in. 44J41 44J41 44J41

“C” Width

“D” Width

Models

15F74 - - -

Models

High Altitude

Input

Pressure Switch Kit

4501 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 0 - 7500 ft. 7501- 10,000 ft.

all models 74W90 74W91 69W73 73W81 73W37

INSTALLATION CLEARANCES - INCHES (MM)

Top/Plenum 1 inch (25 mm)

Front (service/alcove) 24 inches (610 mm)

NOTE − Air for combustion must conform to the methods outlined in the National Fuel Gas Code (NFPA 54/ANSI−Z223.1)

or the National Standard of Canada CAN/CSA−B149.1 Natural Gas and Propane Installation Code”.

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. In Canada ue sizing must conform to the methods outlined in National Standard of Canada CAN/CSA−B149.1.

Allow proper clearances to accommodate condensate trap and vent pipe installation.

Do not install the furnace directly on carpeting, tile, or other combustible materials other than wood ooring.

GAS HEAT ACCESSORIES

Natural Gas to

LPG/Propane Kit

Sides

0 inches (0 mm)

Rear 0 inches (0 mm)

Front 0 inches (0 mm)

Floor

Combustible

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LPG/Propane

to Natural Gas Kit

Natural Gas

High Altitude

Orice Kit

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BLOWER DATA

ML193UH045P36B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1600 700 1370 590 1160 475 1005 400

0.10 1600 685 1355 565 1155 465 1015 390

0.20 1550 650 1330 540 1150 445 1000 380

0.30 1480 625 1295 515 1140 430 975 365

0.40 1425 590 1280 490 1105 415 975 350

0.50 1355 565 1190 460 1085 395 940 335

0.60 1320 545 1165 435 1030 375 900 315

0.70 1225 500 111 0 425 975 355 855 310

0.80 1135 480 1050 395 920 330 780 280

0.90 1025 445 950 360 800 295 700 255

ML193UH070P24B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1140 455 920 365 765 295 710 265

0.10 1135 445 900 360 765 290 690 255

0.20 1125 430 895 350 755 285 680 255

0.30 1090 415 870 340 725 280 660 250

0.40 1065 405 870 325 715 270 635 245

0.50 1020 390 825 315 675 260 605 235

0.60 945 365 780 300 640 250 555 225

0.70 910 350 740 295 585 240 505 220

0.80 790 325 670 275 510 225 455 205

0.90 735 310 575 255 460 220 390 195

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-

High

Medium-

Low

Medium-

Low

ML193UH090P36C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1620 745 1340 620 1130 500 965 405

0.10 1610 720 1335 595 1135 490 975 395

0.20 1565 695 1335 565 1145 465 970 385

0.30 1525 665 1300 555 1135 455 970 370

0.40 1485 635 1295 520 1110 435 960 355

0.50 1431 600 1260 495 1090 405 940 345

0.60 1365 570 1210 475 1035 390 900 330

0.70 1295 535 1155 445 995 365 860 305

0.80 1200 505 1065 415 930 340 745 270

0.90 1060 460 955 375 820 305 695 260

ML193UH090P48C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2025 900 1690 780 1395 645 1200 540

0.10 1995 880 1705 760 1390 635 1205 525

0.20 1925 835 1675 715 1405 605 1205 505

0.30 1850 795 1640 680 1400 580 1170 490

0.40 1790 760 1575 645 1395 560 1170 475

0.50 1700 725 1540 625 1350 535 1140 450

0.60 1610 690 1455 580 1295 505 1100 430

0.70 1540 645 1365 550 1225 480 1030 405

0.80 1415 615 1265 510 1125 445 980 385

0.90 1270 565 1165 470 1060 420 900 350

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-

High

Medium-

Low

Medium-

Low

ML193UH070P36B PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 1615 680 1355 570 1140 480 1030 400

0.10 1565 660 1365 545 1150 465 1020 385

0.20 1535 630 1340 525 1150 440 1025 375

0.30 1440 600 1300 500 1110 420 1000 350

0.40 1405 570 1255 470 1075 400 975 345

0.50 1340 535 1200 445 1045 380 945 330

0.60 1255 500 1125 420 995 355 875 310

0.70 1165 475 1080 395 935 335 820 290

0.80 1060 455 990 365 870 315 750 265

0.90 955 425 895 345 750 285 660 245

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

Medium-

Low

ML193UH110P48C PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2030 905 1750 805 1425 665 1225 530

0.10 1950 865 1755 770 1430 630 1215 515

0.20 1935 840 1675 735 1455 610 1230 505

0.30 1885 810 1660 685 1410 585 1200 485

0.40 1830 780 1585 645 1385 570 1190 470

0.50 1750 740 1565 630 1320 535 1165 455

0.60 1660 695 1485 585 1280 505 1105 425

0.70 1540 665 1380 555 1230 485 1060 405

0.80 1420 615 1290 520 1140 445 945 375

0.90 1290 575 1175 470 1045 410 850 350

Air Volume / Watts at Various Blower Speeds

High

cfm Watts cfm Watts cfm Watts cfm Watts

Medium-

High

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Medium-

Low

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BLOWER DATA

ML193UH110P60C PERFORMANCE (Less Filter)

Air Volume / Watts at Different Blower Speeds

External

Static

Pressure

in. w.g.

0.00 2525 1560 2175 1165 1820 905 1465 725 2520 1545 2135 1150 1750 905 1445 720

0.10 2585 1545 2200 1135 1860 900 1475 710 2555 1545 2135 1115 1775 890 1470 715

0.20 2515 1505 2150 1110 1840 890 1490 705 2465 1480 2105 1085 1775 875 1465 705

0.30 2445 1445 2135 1065 1790 870 1500 690 2370 1430 2045 1055 1750 855 1460 690

0.40 2340 1385 2065 1035 1770 845 1500 675 2275 1375 1990 1010 1730 830 1460 680

0.50 2230 1350 1985 985 1755 810

0.60 2130 1295 1920 950 1685 785 1425 640 2060 1290 1850 935 1650 780 1420 635

0.70 2030 1250 1815 905 1640 760 1405 625 1930 1230 1760 900 1580 750 1355 610

0.80 1920 1190 1735 865 1560 725 1350 605 1825 1180 1660 855 1505 710 1290 585

0.90 1735 1135 1620 830 1450 685 1270 575 1665 1130 1520 810 1415 675 1210 560

ML193UH135P60D PERFORMANCE (Less Filter)

External

Static

Pressure

in. w.g.

0.00 2800 1715 2155 1160 1730 900 1375 695 2720 1685 2110 1135 1670 905 1355 705

0.10 2770 1665 2170 1145 1740 895 1415 700 2660 1650 2110 1115 1725 895 1390 700

0.20 2690 1635 2150 1110 1770 890 1450 700 2600 1585 2125 1090 1750 885 1450 695

0.30 2590 1560 2140 1080 1785 870 1455 695 2535 1525 2075 1065 1750 865 1465 685

0.40 2500 1535 2105 1055 1785 855 1475 690 2400 1490 2055 1030 1715 845 1460 680

0.50 2420 1465 2050 1025 1770 835

0.60 2330 1410 2015 995 1720 810 1460 655 2270 1385 1950 970 1720 800 1445 650

0.70 2225 1370 1965 960 1690 785 1450 650 2175 1335 1895 950 1665 780 1430 635

0.80 2150 1335 1875 925 1655 755 1435 630 2075 1295 1840 910 1605 745 1400 620

0.90 2025 1290 1830 890 1575 720 1375 605 1975 1255 1755 875 1540 725 1340 590

Bottom Return Air, Side Return Air with Optional Return Air Base, Return Air from Both Sides or Return Air from Bottom and One Side.

High Medium-High Medium-Low Low High Medium-High Medium-Low Low

cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts

1470 665 2185 1345 1930 970 1690 800 1460 655

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.

High Medium-High Medium-Low Low High Medium-High Medium-Low Low

cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts

1465 665 2335 1420 2000 1005 1725 825 1455 660

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.

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.

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ML193UH PARTS IDENTIFICATION

FLEXIBLE NO−HUB EXHAUST COLLAR

MANIFOLD

GAS VALVE

FLUE COLLAR

COMBUSTION AIR

INDUCER

BURNER ACCESS

PANEL

BURNER BOX

ASSEMBLY

COMBUSTION

AIR PRESSURE

SWITCH

DuralokPlus

HEAT EXCHANGER

ASSEMBLY

TOP CAP

PRIMARY LIMIT

CABINET

BAG ASSEMBLIES

(shipping location)

SIGHT GLASS

BLOWER

ACCESS

DOOR

COLD END

HEADER BOX

BLOWER

ASSEMBLY

CONTROL BOX

(includes integrated itegrated control, transformer and interlock switch)

FIGURE 1

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I−UNIT COMPONENTS

ML193UH unit components are shown in figure 1. The combustion air inducer, gas valve and burners can be accessed by removing the burner access panel. The blower and control box can be accessed by removing the blower access door.

A−Control Box Components (Figure 2)

Unit transformer (T1) and integrated ignition control (A92) are located in the control box. In addition, a door interlock switch (S51) is located in the control box.

ML193UH Control Box

TRANSFORMER

(T1)

DOOR INTERLOCK

SWITCH (S51)

INTEGRATED IGNITION

CONTROL

(A92)

FIGURE 2

1. Transformer (T1)

A transformer located in the control box provides power to the low voltage section of the unit. The transformers on all models are rated at 40VA with a 120V primary and 24V secondary.

2. Door Interlock Switch (S51)

A door interlock switch rated 14A at 120VAC is located on the control box. The switch is wired in series with line voltage. When the blower door is removed the unit will shut down.

3. Integrated Ignition Control (A92)

WARNING

Shock hazard. Disconnect power before servicing. Control is not

field repairable. If control is inoperable, simply replace entire control.

Can cause injury or death. Unsafe operation will result if repair is attempted.

integrated control also features two LED lights (DS1 red and DS2 green) for troubleshooting and two accessory terminals rated at (1) one amp. The integrated control also features a (3) amp fuse for overcurrent protection. Tables 1 and 2 show jack plug terminal designations. See table 3 for troubleshooting diagnostic codes. The mini−nitride ignitor is made from a non−porous, high strength proprietary ceramic material 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.

TABLE 1

4−Pin Terminal Designation

PIN # FUNCTION

1 Combustion Air Inducer Line

Ignitor Line

Combustion Air Inducer Neutral

Ignitor Neutral

TABLE 2

12−Pin Terminal Designations

PIN # FUNCTION

1 High Limit Output

2 Not Used

3 24V Line

4 Not Used

5 Rollout Switch Out

6 24V Neutral

7 High Limit Input

8 Ground

9 Gas Valve Common

10 Pressure Switch In

11 Rollout Switch In

12 Gas Valve Out

Electronic Ignition (See Figure 5)

On a call for heat the integrated control monitors the combustion air inducer prove switch. The integrated control will not begin the heating cycle if the prove switch is closed (by− passed). Once the prove switch is determined to be open, the combustion air inducer is energized. When the differential in the prove switch is great enough, the prove switch closes and a 15−second pre−purge begins. If the prove 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.

The ignition control system consists of an integrated control (figure 4) ignitor (figure 6) and flame sensor (figure 6). The integrated control and ignitor work in combination to ensure furnace ignition and ignitor durability. The integrated control, controls all major furnace operations. The

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After the 15−second pre−purge period, the ignitor warms up for 20 seconds during which the gas valve opens at 19 seconds 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 integrated control will try four more times with an inter purge and warm−up time between trials of 35 seconds. After a total of five trials for ignition (including the initial trial), the integrated 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 power regulation to maintain consistent lighting and longer ignitor life under all line voltage conditions.

Fan Control

The fan on time of 30 seconds is not adjustable. The fan off delay (amount of time that the blower operates after the heat demand has been satisfied) may be adjusted by

INTEGRATED CONTROL

(Automatic Hot Surface Ignition System)

changing the jumper position across the five pins on the integrated control. The unit is shipped with a factory fan off setting of 90 seconds. The fan off delay affects comfort and is adjustable to satisfy individual applications. Adjust the fan off delay to achieve a supply air temperature between 90° and 110°F at the moment that the blower is de−energized. Longer off delay settings provide lower return air temperatures; shorter settings provide higher return air temperatures. See figure 3.

FAN-OFF TIME IN SECONDS

NO JUMPER

To adjust fan−off timing, reposition jumper across pins

to achieve desired setting.

FIGURE 3

LED 1

LED 2

HUM LINE XFMR EAC COOL HEAT PARK FLAME NEUTRALS

3 AMP, 32 VAC FUSE

TERMINAL DESIGNATIONS

Humidifier (120VAC) Input (120VAC) Transformer (120VAC) Electronic Air Cleaner (120VAC) Blower − Cooling Speed (120VAC) Blower − Heating Speed (120VAC) Dead terminals to park alternate spd taps Flame sensor Neutral terminals (120VAC)

BLOWER OFF

DELAY JUMPER

FIGURE 4

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The integrated control is equipped with two LED lights for troubleshooting. The diagnostic codes are listed below in table 3.

ЙЙЙЙЙЙЙЙЙ

TABLE 3

DIAGNOSTIC CODES

Make sure to Identify LED’S Correctly.

LED #1 (Red) LED #2 (Green) DESCRIPTION

SIMULTANEOUS

SLOW FLASH

SIMULTANEOUS

FAST FLASH

SLOW FLASH ON

OFF SLOW FLASH

ALTERNATING

SLOW FLASH

SLOW FLASH OFF Flame sensed without gas valve energized.

ON SLOW FLASH Rollout switch open. OR: 12-pin connector improperly attached.

SIMULTANEOUS

SLOW FLASH

SIMULTANEOUS

FAST FLASH

ALTERNATING

SLOW FLASH

Power on − Normal operation. Also signaled during cooling and continuous fan.

Normal operation − signaled when heating demand initiated at thermostat.

Primary or secondary limit switch open. Limit must close within 3 minutes or unit goes into 1 hour Watchguard.

Pressure prove switch open. OR: Blocked inlet/exhaust vent; OR: Pressure switch closed prior to activation of combustion air inducer.

Watchguard 1 hour −− burners failed to ignite or lost flame 5 times during single heating demand.

OFF

Circuit board failure or control wired incorrectly.

FAST FLASH SLOW FLASH Main power polarity reversed. Switch line and neutral.

SLOW FLASH FAST FLASH Low flame signal. Measures below 1.5 microamps. Replace flame sense rod.

ALTERNATING

FAST FLASH

ALTERNATING

FAST FLASH

Improper main ground. OR: Line voltage below 90 volts.

NOTE − Slow flash rate equals 1 Hz (one flash per second). Fast flash rate equals 3 Hz (three flashes per second). Minimum flame sense current = 0.5 microAmps.

Sec.Trial

for Ign.

**Blower On"

Delay

End of

Heat Demand

5 SEC

Post

Purge

Blower

Off

Time

OFF

DEMAND

CAI IGNITOR GAS VALVE INDOOR BLOWER

*Ignitor will energize the first 3 seconds of the 4 second trial for ignition

**Blower on time will be 45 seconds after gas valve is energized. Blower off time will depend on OFF TIME" Setting.

15 Sec.

Pre −Purge

20 sec.

Ignitor Warmup

FIGURE 5

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B−Heating Components

Combustion air inducer (B6), primary limit control (S10), SureLight ignitor, burners, flame rollout switch (S47), gas valve (GV1), combustion air prove switch (S18), and clamshell heat exchangers are located in the heating compartment. The heating compartment can be accessed by removing the burner access panel.

1. Ignitor (Figure 6)

ML193UH units use a mini−nitride ignitor made from a proprietary ceramic material. Ignitor longevity is enhanced by controlling the voltage to the ignitor. Due to this feature of the integrated control, voltage cannot be measured. To check ignitor, measure its resistance. A value of 50 to 450 ohms indicates a good ignitor.

2. Flame Sensor (Figure 6)

A flame sensor is located on the left side of the burner support. The sensor is mounted on the front burner box plate and the tip protrudes into the flame envelope of the left− most burner. The sensor can be removed for service without removing any part of the burners. During operation, flame is sensed by current passed through the flame and sensing electrode. The ignition control allows the gas valve to remain open as long as flame signal is sensed.

NOTE − The ML193UH furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded.

3. Flame Rollout Switches (Figure 6)

Flame rollout switches S47 are SPST N.C. high temperature limits located on the top left and bottom right of the front buner box plate. S47 is wired to the burner ignition control A92. When either of the switches sense flame rollout (indicating a blockage in the combustion passages), the flame rollout switch trips, and the ignition control immediately closes the gas valve. Switch S47 in all ML193UH units is factory preset to open at 210_F + 12_F (99_C + 6.7_C) on a temperature rise. All flame rollout switches are manual reset.

FRONT BURNER BOX PLATE

ROLLOUT SWITCHES

FLAME SENSOR

ML193UH Burner Box Assembly

BURNERS

IGNITOR

ORIFICES

GAS VALVE

FIGURE 6

Page 10

Page 11

4. Primary Limit Control (Figure 7)

Primary limit (S10) used on ML193UH units is located in the heating vestibule panel. When excess heat is sensed in the heat exchanger, the limit will open. Once the limit opens, the furnace control energizes the supply air blower and de−energizes the gas valve. The limit automatically resets when unit temperature returns to normal. The switch is factory set and cannot be adjusted. For limit replacement remove wires from limit terminals, remove mounting screws, rotate limit switch 90 degrees and slowly remove from the vestibule panel. Install replacement limit with same care.

an orifice which is precisely matched to the burner input. See table 4 for orifice size. The burner is supported by the orifice and will easily slide off for service. A flame retention ring in the end of each burner maintains correct flame length and shape and keeps the flame from lifting off the burner head.

TABLE 4

Gas Orifice Size

Unit Fuel Orifice Size

All Natural 0.0625

All L.P./Propane 0.0340

Primary Limit Location and Heat Exchanger

Install limit face down

FIGURE 7

5. Heat Exchanger (Figure 7)

ML193UH units use an aluminized steel primary and stainless steel secondary heat exchanger assembly. Heat is transferred to the air stream from all surfaces of the heat exchanger. The shape of the heat exchanger ensures maximum efficiency.

The combustion air inducer pulls fresh air through the burner box. This air is mixed with gas in the burners. The gas / air mixture is then burned at the entrance of each clamshe ll. Combustion gases are then pulled through the primary and secondary heat exchangers and exhausted out the exhaust vent pipe.

6. Burners (Figure 8)

All units use inshot burners. Burners are factory set and do not require adjustment. Burners can be removed as an assembly for service. Burner maintenance and service is detailed in the MAINTENANCE section of this manual. Each burner uses

Burner Detail Top View

IGNITOR

FLAME SENSOR

ORIFICES

FIGURE 8

7. Gas Valve (GV1)

The ML193UH uses an internally redundant valve to assure safety shut-off. If the gas valve must be replaced, the same type valve must be used.

24VAC terminals and gas control switch are located on top of the valve. All terminals on the gas valve are connected to wires from the ignition control. 24V applied to the terminals opens the valve.

Inlet and outlet pressure taps are located on the valve. A manifold adjustment screw is also located on the valve. An LPG changeover kit is available.

MANIFOLD

PRESSURE

ADJUSTMENT

SCREW

INLET

PRESSURE

PORT

Gas Valve

MANIFOLD

PRESSURE

OUTLET

PORT

FIGURE 9

Page 11

Page 12

8. Combustion Air Inducer (B6) & Cold End Header Box

All ML193UH units use a combustion air inducer to move air through the burners and heat exchanger during heating operation. The blower uses a shaded pole 120VAC motor. The motor operates during all heating operation and is controlled by integrated control A3. Blower operates continuously while there is a call for heat. The integrated control will not proceed with the ignition sequence until combustion air inducer operation is sensed by the proving switches.

The combustion air inducer is installed on the cold end header box. The cold end header box is a single piece made of hard plastic. The box has an internal channel where the combustion air inducer creates negative pressure at unit start up. The channel contains an orifice used to regulate flow created by the combustion air inducer. The box has pressure taps for the combustion air inducer pressure switch hoses. The pressure switch measures the pressure across the combustion air inducer orifice or difference in the channel and the box. If replacement is

necessary the gaskets used to seal the box to the vestibule panel and the combustion air inducer to the box, must also be replaced.

TABLE 5

ML193UH Unit Combustion Air Inducer

Orifice Size

−045 0.563

−070 0.844

−090 1.00

−110 1.22

−135 1.30

9. Combustion Air Pressure Switch (Figure 10)

ML193UH series units are equipped with a differential pressure switch located on the cold end header box. The switch monitors across the combustion air inducer orifice to insure proper flow through the heat exchanger.

The switch is a SPST N.O. prove switch electrically connected to the integrated control. The purpose of the switch is to prevent burner operation if the combustion air inducer is not moving enough air for proper combustion.

Pressure Switch

FIGURE 10

On start-up, the switch monitors whether the combustion air inducer is operating. It closes a circuit to the integrated control when the difference in pressure across the combustion air inducer orifice exceeds a non−adjustable factory setting. If the switch does not successfully sense the required differential, the switch cannot close and the furnace cannot operate. If the flue or air inlet become obstructed during operation, the switch senses a loss of pressure differential and opens the circuit to the integrated control. If the condensate line is blocked, water will back up into the header box and reduce the pressure differential across the switch. The prove switch opens if the differential drops below the set point. See table 6.

Checks of pressure differential can aid in troubleshooting. When measuring the pressure differential, readings should be taken at the pressure switch. See figure 11. Lack of differential usually indicates problems in the intake or exhaust piping, but may indicate problems in the heat exchanger, condensing coil, header boxes, combustion inducer or other components.

TABLE 6

Altitude ft.

Unit

−045

−070

−090

−110

−135

*Set point is factory set and non−adjustable

0 − 4500 4501 − 7500 7501 − 10000

Set Point w.c. Set Point w.c Set Point w.c.

−0.65 −0.60 −0.055

Page 12

Page 13

Measuring Pressure Differential

RED TUBING

NEGATIVE

BLACK TUBING

POSITIVE

1 − Remove thermostat demand and allow unit to

cycle off.

2 − Install a tee in the negative (−) line (red tubing) and a

tee in the positive (+) line (black tubing) running from the pressure switch to the cold end header box.

3 − Install a manometer with hose from the negative (−)

side of the manometer to the tee installed in the negative (−) line and with hose from the positive (+) side of the manometer to the tee in the positive (+) line.

NOTE − Both sides of the cold end header box are negative. However the (+) port reads less negative pressure than the (−) port.

FIGURE 11

C− Blower Compartment

Blower motor (B3) and capacitor (C4), are located in the blower compartment. The blower compartment can be accessed by removing the blower access panel.

Blower Motor Housing

4 − Operate unit and observe manometer reading.

Readings will change as heat exchanger warms.

a. Take one reading immediately after start-up. b. Take a second reading after unit has reached steady state (approximately 5 minutes). This will be the pressure differential.

The pressure differential should be greater than those listed in table 6.

5 − Remove thermostat demand and allow to cycle off.

6 − Remove manometer and tee’s. Reinstall combustion

air sensing hoses to the pressure switch.

1. Blower Motor (B3) and Capacitor (C4)

All ML193UH units use single−phase direct−drive blower motors. All motors are 120V permanent split capacitor motors to ensure maximum efficiency. See SPECIFICATIONS table at the front of this manual for more detail. See motor nameplate for capacitor ratings.

BOLTS

CAPACITOR

To Remove Blower From Unit: Disconnect Power, Remove Control

Box, Remove Bolts and Unplug Motor Wires From Control. Then

Slide Out Front of Unit.

FIGURE 12

MOTOR

Page 13

Page 14

II−PLACEMENT AND INSTALLATION

Combustion, Dilution & Ventilation Air

If the ML193UH is installed as a Non−Direct Vent Furnace, follow the guidelines in this section.

NOTE − In Non−Direct Vent installations, combustion air is taken from indoors and flue gases are discharged out− doors.

In the past, there was no problem in bringing in sufficient outdoor air for combustion. Infiltration provided all the air that was needed. In today’s homes, tight construction practices make it necessary to bring in air from outside for combustion. Take into account that exhaust fans, appliance vents, chimneys, and fireplaces force additional air that could be used for combustion out of the house. Unless outside air is brought into the house for combustion, negative pressure (outside pressure is greater than inside pressure) will build to the point that a downdraft can occur in the furnace vent pipe or chimney. As a result, combustion gases enter the living space creating a potentially dangerous situation.

In the absence of local codes concerning air for combus− tion and ventilation, use the guidelines and procedures in this section to install ML193UH furnaces to ensure efficient and safe operation. You must consider combustion air needs and requirements for exhaust vents and gas piping. A portion of this information has been reprinted with permission from the National Fuel Gas Code (ANSI− Z223.1/NFPA 54). This reprinted material is not the complete and official position of the ANSI on the referenced subject, which is represented only by the standard in its entirety.

In Canada, refer to the CSA B149 installation codes.

CAUTION

Do not install the furnace in a corrosive or contaminated atmosphere. Meet all combustion and ventilation air requirements, as well as all local codes.

All gas-fired appliances require air for the combustion process. If sufficient combustion air is not available, the furnace or other appliance will operate inefficiently and unsafely. Enough air must be provided to meet the needs of all fuel−burning appliances and appliances such as exhaust fans which force air out of the house. When fireplaces, exhaust fans, or clothes dryers are used at the same time as the furnace, much more air is required to ensure proper combustion and to prevent a downdraft. Insufficient air causes incomplete combustion which can result in carbon monoxide.

In addition to providing combustion air, fresh outdoor air dilutes contaminants in the indoor air. These contaminants may include bleaches, adhesives, detergents, solvents and other contaminants which can corrode furnace components.

The requirements for providing air for combustion and ventilation depend largely on whether the furnace is installed in an unconfined or a confined space.

Unconfined Space

An unconfined space is an area such as a basement or large equipment room with a volume greater than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the combined input rating of all appliances installed in that space. This space also includes adjacent rooms which are not separated by a door. Though an area may appear to be unconfined, it might be necessary to bring in outdoor air for combustion if the structure does not provide enough air by infiltration. If the furnace is located in a building of tight construction with weather stripping and caulking around the windows and doors, follow the procedures in the Air from Outside section.

Confined Space

A confined space is an area with a volume less than 50 cubic feet (1.42 m3) per 1,000 Btu (.29 kW) per hour of the com− bined input rating of all appliances installed in that space. This definition includes furnace closets or small equipment rooms.

When the furnace is installed so that supply ducts carry air circulated by the furnace to areas outside the space containing the furnace, the return air must be handled by ducts which are sealed to the furnace casing and which terminate outside the space containing the furnace. This is especially important when the furnace is mounted on a platform in a confined space such as a closet or small equipment room. Even a small leak around the base of the unit at the platform or at the return air duct connection can cause a potentially dangerous negative pressure condition. Air for combustion and ventilation can be brought into the confined space either from inside the building or from outside.

Air from Inside

If the confined space that houses the furnace adjoins a space categorized as unconfined, air can be brought in by providing two permanent openings between the two spaces. Each opening must have a minimum free area of 1 square inch (645 mm2) per 1,000 Btu (.29 kW) per hour of total input rating of all gas−fired equipment in the confined space. Each opening must be at least 100 square inches (64516 mm2). One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. See figure 13.

Page 14

Page 15

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM INSIDE

ROOF TERMINATED

EXHAUST PIPE

OPENINGS

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

NOTE − Each opening shall have a free area of at least one square inch per 1,000 Btu (645mm all equipment in the enclosure, but not less than 100 square inches (64516mm.

2).

ML193UH

per .29kW) per hour of the total input rating of

(To Adjacent

Unconfined

Space)

FIGURE 13

Air from Outside

If air from outside is brought in for combustion and ventilation, the confined space shall be provided with two permanent openings. One opening shall be within 12" (305mm) of the top of the enclosure and one within 12" (305mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch per 4,000 Btu (645mm per 1.17kW) per hour of total input rating of all equipment in the enclosure. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch per 2,000 Btu (645mm per .59kW) per total input rating of all equipment in the enclosure (See figure 14).

If air from outside is brought in for combustion and ventilation, the confined space must have two permanent openings. One opening shall be within 12 inches (305 mm) of the top of the enclosure and one opening within 12 inches (305 mm) of the bottom. These openings must communicate directly or by ducts with the outdoors or spaces (crawl or attic) that freely communicate with the outdoors or indirectly through vertical ducts. Each opening shall have a minimum free area of 1 square inch (645 mm2) per 4,000 Btu (1.17 kW) per hour of total input rating of all equipment in the enclosure. See figures 14 and 15. When communicating with the outdoors through horizontal ducts, each opening shall have a minimum free area of 1 square inch (645 mm2) per 2,000 Btu (.56 kW) per total input rating of all equipment in the enclosure. See figure 16.

When ducts are used, they shall be of the same cross−sectional area as the free area of the openings to which they connect. The minimum dimension of rectangular air ducts shall be no less than 3 inches (75 mm). In calculating free area, the blocking effect of louvers, grilles, or screens must be considered. If the design and free area of protective covering is not known for calculating the size opening required, it may be assumed that wood louvers will have 20 to 25 percent free area and metal louvers and grilles will have 60 to 75 percent free area. Louvers and grilles must be fixed in the open position or interlocked with the equipment so that they are opened automatically during equipment operation.

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE

(All Air Through Ventilated Attic)

ROOF TERMINATED

EXHAUST PIPE

OUTLET

AIR

VENTILATION LOUVERS

(Each end of attic)

EQUIPMENT IN CONFINED SPACE − ALL AIR FROM OUTSIDE

(Inlet Air from Crawl Space and Outlet Air to Ventilated Attic)

ROOF TERMINATED

EXHAUST PIPE

OUTLET

AIR

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

FURNACE

INLET

AIR

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm hour of the total input rating of all equipment in the enclosure.

FIGURE 14

VENTILATION LOUVERS

(Each end of attic)

VENTILATION

LOUVERS

(For unheated

crawl space)

per 1.17kW) per

Page 15

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

FURNACE

NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch per 4,000 Btu (645mm

INLET AIR

(Ends 12" above

bottom)

per 1.17kW) per hour

of the total input rating of all equipment in the enclosure.

FIGURE 15

Page 16

EQUIPMENT IN CONFINED SPACE −

ALL AIR FROM OUTSIDE

ROOF TERMINATED

EXHAUST PIPE

OUTLET AIR

SIDE WALL

TERMINATED

EXHAUST PIPE

(ALTERNATE

LOCATION)

NOTE−Each air duct opening shall have a free area of at least one square inch per 2,000 Btu (645mm input rating of all equipment in the enclosure. If the equipment room is located against an outside wall and the air openings communicate directly with the outdoors, each opening shall have a free area of at least 1 square inch per 4,000 Btu (645mm hour of the total input rating of all other equipment in the enclosure.

FURNACE

INLET AIR

per .59kW) per hour of the total

per 1.17kW) per

FIGURE 16

Pipe & Fittings Specifications

All pipe, fittings, primer and solvent cement must conform with American National Standard Institute and the American Society for Testing and Materials (ANSI/ASTM) standards. The solvent shall be free flowing and contain no lumps, undissolved particles or any foreign matter that adversely affects the joint strength or chemical resistance of the cement. The cement shall show no gelation, stratification, or separation that cannot be removed by stirring. Refer to the table 7 below for approved piping and fitting materials.

IMPORTANT

ML193UH exhaust and intake connections are made of PVC. Use PVC primer and solvent cement when using PVC vent pipe. When using ABS vent pipe, use transitional solvent cement to make connections to the PVC fittings in the unit.

CAUTION

Solvent cements for plastic pipe are flammable liquids and should be kept away from all sources of ignition. Do not use excessive amounts of solvent cement when making joints. Good ventilation should be maintained to reduce fire hazard and to minimize breathing of solvent vapors. Avoid contact of cement with skin and eyes.

Use PVC primer and solvent cement or ABS solvent cement meeting ASTM specifications, refer to Table 7. As an alternate, use all purpose cement, to bond ABS, PVC, or CPVC pipe when using fittings and pipe made of the same materials. Use transition solvent cement when bonding ABS to either PVC or CPVC.

TABLE 7

PIPING AND FITTINGS SPECIFICATIONS

Schedule 40 PVC (Pipe) D1785 Schedule 40 PVC (Cellular Core Pipe) F891

Schedule 40 PVC (Fittings) D2466

Schedule 40 CPVC (Pipe) F441

Schedule 40 CPVC (Fittings) F438

SDR−21 PVC or SDR−26 PVC (Pipe) D2241

SDR−21 CPVC or SDR−26 CPVC (Pipe) F442

Schedule 40 ABS Cellular Core DWV (Pipe) F628

Schedule 40 ABS (Pipe) D1527

Schedule 40 ABS (Fittings) D2468

ABS−DWV (Drain Waste & Vent) (Pipe & Fittings)

PVC−DWV (Drain Waste & Vent) Pipe & Fittings)

PRIMER & SOLVENT CEMENT

PVC & CPVC Primer F656 PVC Solvent Cement D2564

CPVC Solvent Cement F493

ABS Solvent Cement D2235

PVC/CPVC/ABS All Purpose Cement For Fittings & Pipe of the same material

ABS to PVC or CPVC Transition Solvent Cement

CANADA PIPE & FITTING & SOLVENT

CEMENT

PVC & CPVC Pipe and Fittings PVC & CPVC Solvent Cement

ABS to PVC or CPVC Transition Cement

D2661

D2665

ASTM

SPECIFICATION

D2564, D2235, F493

D3138

MARKING

ULCS636

Low temperature solvent cement is recommended during cooler weather. Metal or plastic strapping may be used for vent pipe hangers. Uniformly apply a liberal coat of PVC primer for PVC or use a clean dry cloth for ABS to clean inside socket surface of fitting and male end of pipe to depth of fitting socket.

Canadian Applications Only − Pipe, fittings, primer and solvent cement used to vent (exhaust) this appliance must be certified to ULC S636 and supplied by a single manufacturer as part of an approved vent (exhaust) system. When bonding the vent system to the furnace, use ULC S636 approved One−Step Transition Cement to bond the pipe to the flue collar, or to bond the 90° elbow or reducing 90° elbow to the flue collar. In addition, the first three feet of vent pipe from the furnace flue collar must be accessible for inspection.

Page 16

Page 17

ML193

UNIT

OUTDOOR TERMINATION KITS USAGE

TABLE 8

STANDARD CONCENTRIC

Outdoor Ex-

VENT

PIPE

DIA.

haust Accel-

erator

(Dia. X

(in.)

2 YES YES YES* YES YES YES

Length)

1−1/2" X 12" 2" X 12"

Outdoor Exhaust Accel-

erator

(Dia. X

Length)

2" Wall Plate

Kit

22G44

or 30G28

3" Wall Plate

Kit

44J40

or 81J20

2" Wall

Ring Kit

15F74 51W11**

FlushMount

Kit

Concentric

44W92

1−1/2"

Kit

71M80

2" Con-

centric Kit

69M29

44W92

3" Con-

centric Kit

60L46

or 44W93

045

070

090

110

135 3 YES YES YES

*Requires field−provided and installed 1−1/2" exhaust accelerator. ** Kit 51W11 is provided with a 1−1/2" accelerator which must be used for all ML193UH−045, −070 and −090 installations.  Termination kits 44W92, 44W93, 30G28 and 81J20 approved for use in Canadian installations to meet CSAB149.  The 44W92 Concentric kit is provided with a 1−1/2" accelerator which must be installed on the exhaust outlet when this kit is used with the ML193UH045P36B,

ML193UH070P24B and ML193UH070P36B

2−1/2 YES YES YES* YES YES YES

3 YES YES YES* YES YES YES

2 YES YES YES* YES YES YES

2−1/2 YES YES YES* YES YES YES

3 YES YES YES* YES YES YES

2 YES YES YES YES YES YES

2−1/2 YES YES YES YES YES YES

3 YES YES YES YES YES YES

2 YES YES YES YES YES YES

2−1/2 YES YES YES YES YES YES

3 YES YES YES YES YES YES

furnaces.

5 − Uniformly apply a liberal coat of PVC primer for PVC or

Joint Cementing Procedure

All cementing of joints should be done according to the specifications outlined in ASTM D 2855.

use a clean dry cloth for ABS to clean inside socket surface of fitting and male end of pipe to depth of fitting socket.

NOTE − Time is critical at this stage. Do not allow primer to dry before applying cement.

DANGER

6 − Promptly apply solvent cement to end of pipe and in-

side socket surface of fitting. Cement should be ap-

DANGER OF EXPLOSION!

Fumes from PVC glue may ignite during system check. Allow fumes to dissipate for at least 5 minutes before placing unit into operation.

plied lightly but uniformly to inside of socket. Take care to keep excess cement out of socket. Apply second coat to end of pipe.

7 − Immediately after applying last coat of cement to pipe,

and while both inside socket surface and end of pipe

1 − Measure and cut vent pipe to desired length.

2 − Debur and chamfer end of pipe, removing any ridges

or rough edges. If end is not chamfered, edge of pipe may remove cement from fitting socket and result in a leaking joint.

3 − Clean and dry surfaces to be joined.

4 − Test fit joint and mark depth of fitting on outside of pipe.

are wet with cement, forcefully insert end of pipe into socket until it bottoms out. Turn PVC pipe 1/4 turn during assembly (but not after pipe is fully inserted) to distribute cement evenly. DO NOT turn ABS or cellular core pipe.

NOTE − Assembly should be completed within 20 seconds after last application of cement. Hammer blows should not be used when inserting pipe.

Page 17

Page 18

8 − After assembly, wipe excess cement from pipe at end

of fitting socket. A properly made joint will show a bead around its entire perimeter. Any gaps may indicate an improper assembly due to insufficient solvent.

9 − Handle joints carefully until completely set.

Venting Practices

CHIMNEY

OR GAS

VENT

(Check sizing

for water

heater only)

FURNACE

(Replaced

by ML193)

REPLACING FURNACE THAT WAS

PART OF A COMMON VENT SYSTEM

WATER

HEATER

Piping Suspension Guidelines

SCHEDULE 40

PVC − 5’

all other pipe* − 3’

* See table 7 for allowable pipe.

NOTE − Isolate piping at the point where it exits the outside wall or roof in order to prevent transmission of vibration to the structure.

Wall Thickness Guidelines

24" maximum 3/4" minimum

inside outside

Wall

insulation

(if required)

FIGURE 17

1 In areas where piping penetrates joists or interior

walls, hole must be large enough to allow clearance on all sides of pipe through center of hole using a hanger.

2. When furnace is installed in a residence where unit is

shut down for an extended period of time, such as a vacation home, make provisions for draining condensate collection trap and lines.

OPENINGS

(To Adjacent

Room)

If an ML193UH furnace replaces a furnace which was commonly vented with another gas appliance, the size of the existing vent pipe for that gas appliance must be checked. Without the heat of the original furnace flue products, the existing vent pipe is probably oversized for the single water heater or other appliance. The vent should be checked for proper draw with the remaining appliance.

FIGURE 18

Exhaust Piping (Figures 21 and 22)

Route piping to outside of structure. Continue with installation following instructions given in piping termination section.

CAUTION

Do not discharge exhaust into an existing stack or stack that also serves another gas appliance. If vertical discharge through an existing unused stack is required, insert PVC pipe inside the stack until the end is even with the top or outlet end of the metal stack.

CAUTION

The exhaust vent pipe operates under positive pressure and must be completely sealed to prevent leakage of combustion products into the living space.

Page 18

Page 19

Vent Piping Guidelines

The ML193UH can be installed as either a Non−Direct Vent or a Direct Vent gas central furnace.

NOTE − In Non-Direct Vent installations, combustion air is taken from indoors and flue gases are discharged outdoors. In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged outdoors.

Intake and exhaust pipe sizing −− Size pipe according to

tables 9 and 10. Table 9 lists the minimum vent pipe lengths permitted. Table 10 lists the maximum pipe lengths permitted.

Regardless of the diameter of pipe used, the standard roof and wall terminations described in section Exhaust Piping Terminations should be used. Exhaust vent termination pipe is sized to optimize the velocity of the exhaust gas as it exits the termination. Refer to table 11.

In some applications which permit the use of several different sizes of vent pipe, a combination vent pipe may be used. Contact Lennox’ Application Department for assistance in sizing vent pipe in these applications.

NOTE − The exhaust collar on all models is sized to accommodate 2" Schedule 40 vent pipe. When vent pipe which is larger than 2" must be used in an upflow application, a transition must be applied at the exhaust collar in order to properly step to the larger diameter vent pipe. Contact the Application Department for more information concerning sizing of vent systems which include multiple pipe sizes.

Use the following steps to correctly size vent pipe diameter.

Furnace capacity?

Which termination?

Which needs most elbows?

How many?

045, 070, 090, 110 or 135 btuh

Standard or Concentric? See table 8

Intake or exhaust

Exhaust Pipe

12" Min.

12" max

of straight pipe

Horizontal Application

NOTE − All horizontal runs of exhaust pipe must slope back toward unit. A minimum of 1/4" (6mm) drop for each 12" (305mm) of horizontal run is mandatory for drainage.

NOTE − Exhaust pipe MUST be glued to furnace exhaust fittings.

NOTE − Exhaust piping should be checked carefully to make

sure there are no sags or low spots.

FIGURE 19

TABLE 9

MINIMUM VENT PIPE LENGTHS

ML193UH

MODEL

045, 070, 090, 110

135**

*Any approved termination may be added to the minimum length listed. **ML193UH135P60D must have 3" to 2" reducing ell (supplied or field replacement Canadian kit) installed directly into unit flue collar.

MIN. VENT LENGTH*

15 ft. or

5 ft plus 2 elbows or

10 ft plus 1 elbow

Desired pipe size?

What is the altitude?

Use table 5 to find

max. pipe length.

2", 2 1/2", 3"

FIGURE 20

IMPORTANT

Do not use screens or perforated metal in exhaust or intake terminations. Doing so will cause freeze−ups and may block the terminations.

Page 19

Page 20

Number

Of 90°

Ebows

Used

Number

Of 90°

Ebows

Used

Maximum Allowable Vent Length in Feet

TABLE 10

Standard Termination at Elevation 0 − 10,000 ft.

Pipe Size

Model 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135

1 81 66 44 24 2 76 61 39 19 11 0 95 63 38 132 132 113 113 109 3 71 56 34 14 105 90 58 33 127 127 108 108 104 4 66 51 29 5 61 46 24 95 80 48 23 11 7 11 7 98 98 94 6 56 41 19 90 75 43 18 11 2 11 2 93 93 89 7 51 36 14 85 70 38 13 107 107 88 88 84 8 46 31 9 41 26 75 60 28 97 97 78 78 74

10 36 21 70 55 23 92 92 73 73 69

Pipe Size

Model 045 070 090 110 135 045 070 090 110 135 045 070 090 110 135

1 73 58 42 22 2 68 53 37 17 100 85 59 34 116 116 109 109 100 3 63 48 32 12 95 80 54 29 111 111 104 104 95 4 58 43 27 5 53 38 22 85 70 44 19 101 101 94 94 85 6 48 33 17 80 65 39 14 96 96 89 89 80 7 43 28 12 75 60 34 8 38 23 9 33 18 65 50 24 81 81 74 74 65

10 28 13 60 45 19 76 76 69 69 60

2" 2−1/2" 3"

115 100 68 43

100 85 53 28 122 122 103 103 99

n/a

80 65 33

n/a

Concentric Termination Elevation 0 − 10,000 ft.

2" 2−1/2" 3"

105 90 64 39

90 75 49 24 106 106 99 99 90

n/a

70 55 29 86 86 79 79 70

n/a

137 137 118 118 114

n/a

102 102 83 83 79

121 121 114 114 105

n/a

91 91 84 84 75

Page 20

Page 21

TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION

IN UPFLOW DIRECT OR NON−DIRECT VENT APPLICATIONS

Pipe size determined in table 10

3”

TRANSITION

2”

TRAP

Use only the

factory−supplied trap.

Trap can be installed

on either side of

cabinet within 5 ft. of

the furnace.

TYPICAL EXHAUST PIPE CONNECTIONS AND CONDENSATE TRAP INSTALLATION

2”

EXHAUST

2”

DO NOT transition

from smaller to larger

pipe in horizontal runs

of exhaust pipe.

FIGURE 21

IN HORIZONTAL DIRECT OR NON−DIRECT VENT APPLICATIONS

(RIGHT HAND DISCHARGE SHOWN)

12" max.

2”

EXHAUST

Use only the factory−supplied

trap. Trap can be installed

within 5 ft. of the furnace and

MUST be installed on left side

for left−hand discharge.

2”

FIGURE 22

45°

MAX

3”

2”

TRANSITION

2”

SIDE VIEW

45°

MAX

DO NOT transition

from smaller to larger

pipe in horizontal runs

of exhaust pipe.

Page 21

Page 22

3”

TRANSITION

TYPICAL AIR INTAKE PIPE CONNECTIONS IN UPFLOW

DIRECT VENT APPLICATIONS

Pipe size determined in table 10

2”

AIR INTAKE

TRAP

*2”

2”

Use only the factory−supplied trap. Trap can be installed on either side of cabinet within 5

ft. of the furnace.

2”

FIGURE 23

TYPICAL AIR INTAKE PIPE CONNECTIONS IN HORIZONTAL DIRECT VENT APPLICATIONS

(RIGHT HAND DISCHARGE SHOWN)

2”

AIR INTAKE

Use only the factory−supplied trap. Trap can be installed within 5 ft. of the furnace and MUST be installed on left

side for left−hand discharge.

2”

FIGURE 24

3”

2”

TRANSITION

2”

Page 22

Page 23

Intake Piping The ML193UH furnace may be installed in either direct

vent or non−direct vent applications. In non−direct vent

applications, when intake air will be drawn into the furnace from the surrounding space, the indoor air quality must be considered and guidelines listed in Combustion, Dilution and Ventilation Air section must be followed.

Follow the next two steps when installing the unit in Direct Vent applications, where combustion air is taken from outdoors and flue gases are discharged outdoors. The

provided air intake screen must not be used in direct vent applications (outdoors).

1 − Use transition solvent cement or a sheet metal screw

to secure the intake pipe to the inlet air connector.

2 − Route piping to outside of structure. Continue with

installation following instructions given in general guide lines for piping terminations and intake and exhaust piping terminations for direct vent sections. Refer to table 10 for pipe sizes.

TYPICAL AIR INTAKE PIPE CONNECTIONS

UPFLOW NON−DIRECT

VENT APPLICATIONS

INTAKE

DEBRIS

SCREEN

(Provided)

TYPICAL AIR INTAKE PIPE CONNECTIONS

HORIZONTAL NON−DIRECT VENT APPLICATIONS

(Horizontal Right−Hand Air Discharge Application Shown)

PVC pipe

coupling

INTAKE DEBRIS

SCREEN

(Provided)

NOTE − Debris screen may be positioned straight out (preferred) or with an elbow rotated to face down.

FIGURE 26 Follow the next two steps when installing the unit in NonDirect Vent applications where combustion air is taken from indoors and flue gases are discharged outdoors.

1 − Use field−provided materials and the factory−provided

air intake screen to route the intake piping as shown in figure 25 or 26. Maintain a minimum clearance of 3" (76mm) around the air intake opening. The air intake opening (with the protective screen) should always be directed forward or to either side in the upflow position, and either straight out or downward in the horizontal position.

The air intake piping must not terminate too close to the flooring or a platform. Ensure that the intake air inlet will not be obstructed by loose insulation or other items that may clog the debris screen.

2 − Use a sheet metal screw to secure the intake pipe to

the connector, if desired.

NOTE − Debris screen and elbow may be rotated, so that screen may be positioned to face forward or to either side.

FIGURE 25

Page 23

Page 24

General Guidelines for Vent Terminations

In Non-Direct Vent applications, combustion air is taken from indoors and the flue gases are discharged to the outdoors. The ML193UH is then classified as a non-direct vent, Category IV gas furnace.

In Direct Vent applications, combustion air is taken from outdoors and the flue gases are discharged to the outdoors. The ML193UH is then classified as a direct vent, Category IV gas furnace.

In both Non-Direct Vent and Direct Vent applications, the vent termination is limited by local building codes. In the absence of local codes, refer to the current National Fuel Gas Code ANSI Z223−1/NFPA 54 in U.S.A., and current CSA−B149 Natural Gas and Propane Installation Codes in Canada for details.

Position termination according to location given in figure 27 or 28. In addition, position termination so it is free from any obstructions and 12" above the average snow accumulation.

At vent termination, care must be taken to maintain protective coatings over building materials (prolonged exposure to exhaust condensate can destroy protective coatings). It is recommended that the exhaust outlet not be located within 6 feet (1.8m) of a condensing unit because the condensate can damage the painted coating.

NOTE − If winter design temperature is below 32°F (0°C), exhaust piping should be insulated with 1/2" (13mm), Armaflex or equivalent when run through unheated space. Do not leave any surface area of exhaust pipe open to outside air; exterior exhaust pipe should be insulated with

1/2" (13mm) Armaflex or equivalent. In extreme cold climate areas, 3/4" (19mm) Armaflex or equivalent may be necessary. Insulation on outside runs of exhaust pipe must be painted or wrapped to protect insulation from deterioration. Exhaust pipe insulation may not be necessary in some specific applications.

NOTE − During extremely cold temperatures, below approximately 20°F (6.7°C), units with long runs of vent pipe through unconditioned space, even when insulated, may form ice in the exhaust termination that prevents the unit from operating properly. Longer run times of at least 5 minutes will alleviate most icing problems. Also, a heating cable may be installed on exhaust piping and termination to prevent freeze−ups. Heating cable installation kit is available from Lennox. See Condensate Piping section for part numbers.

IMPORTANT

Do not use screens or perforated metal in exhaust terminations. Doing so will cause freeze−ups and may block the terminations.

IMPORTANT

For Canadian Installations Only: In accordance to CSA International B149 installation codes, the minimum allowed distance between the combustion air intake inlet and the exhaust outlet of other appliances shall not be less than 12 inches (305mm).

Page 24

Page 25

VENT TERMINATION CLEARANCES

FOR NON−DIRECT VENT INSTALLATIONS IN THE USA AND CANADA

INSIDE CORNER

DETAIL

Fixed

Closed

Operable

VENT TERMINAL

AIR SUPPLY INLET

US Installations

A =

B =

C =

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

Clearance to permanently

12 inches (305mm) or 12 in. 305mm)

above average snow accumulation.

4 feet (1.2 m) below or to side of opening;

1 foot (30 cm) above opening

closed window

D =

Vertical clearance to ventilated soffit

located above the terminal within a

* Equal to or greater than soffit depth.

horizontal distance of 2 feet (mm)

from the center line of the terminal

E =

F =

G =

H =

I =

J =

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line ex-

tended above meter / regulator assembly

Clearance to service regulator

vent outlet

Clearance to non−mechanical air

supply inlet to building or the com-

bustion air inlet to any other ap-

* Equal to or greater than soffit depth.

* No minimum to outside corner * No minimum to outside corner

* 3 feet (.9m) * 3 feet (.9m)

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

* 3 feet (.9m)

4 feet (1.2 m) below or to side of opening;

1 foot (30 cm) above opening

pliance

K =

L =

Clearance to mechanical air sup-

ply inlet

Clearance above paved sidewalk or

3 feet (.9m) above if within 10 feet

(3m) horizontally

7 feet (2.1m)

paved driveway located on public property

M =

 A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

 Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible.

Clearance under veranda, porch,

deck or balcony

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code

*12 inches (305mm)

FIGURE 27

Operable

Fixed

Closed

AREA WHERE TERMINAL IS NOT PERMITTED

Canadian Installations

12 inches (305mm) or 12 in. 305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

* 12"

* Equal to or greater than soffit depth.

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

6 feet (1.8m)

7 feet (2.1m)

12 inches (305mm)

*For clearances not specified in ANSI Z223.1/NFPA 54 or CSA B149.1, clearance will be in accordance with local installation codes and the requirements of the gas supplier and these installation instructions."

Page 25

Page 26

VENT TERMINATION CLEARANCES

FOR DIRECT VENT INSTALLATIONS IN THE USA AND CANADA

INSIDE CORNER

DETAIL

Fixed

Closed

Operable

VENT TERMINAL

AIR SUPPLY INLET

US Installations

A =

B =

Clearance above grade, veranda,

porch, deck or balcony

Clearance to window or

door that may be opened

12 inches (305mm) or 12 in. 305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (mm) for appliances

> 10,000 Btuh (3kw) and <50,000 Btuh

(15 kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

C =

Clearance to permanently

closed window

D =

Vertical clearance to ventilated soffit

located above the terminal within a

* Equal to or greater than soffit depth

horizontal distance of 2 feet (mm)

from the center line of the terminal

E =

F =

G =

H =

Clearance to unventilated soffit

Clearance to outside corner

Clearance to inside corner

Clearance to each side of center line ex-

tended above meter / regulator assembly

I =

Clearance to service regulator

vent outlet

J =

Clearance to non−mechanical air

supply inlet to building or the com-

bustion air inlet to any other ap-

pliance

* Equal to or greater than soffit depth * Equal to or greater than soffit depth

* No minimum to outside corner

* 3 feet (.9m)

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 9 inches (mm) for appliances

> 10,000 Btuh (3kw) and <50,000 Btuh

(15 kw), 12 inches (305mm) for ap-

pliances > 50,000 Btuh (15kw)

K =

L =

M =

 A vent shall not terminate directly above a sidewalk or paved driveway that is located between two single family dwellings and serves both dwellings.

 Permitted only if veranda, porch, deck or balcony is fully open on a minimum of two sides beneath the floor. Lennox recommends avoiding this location if possible.

Clearance to mechanical air sup-

ply inlet

Clearance above paved sidewalk or

paved driveway located on public property

Clearance under veranda, porch,

deck or balcony

In accordance with the current ANSI Z223.1/NFPA 54 Natural Fuel Gas Code

In accordance with the current CSA B149.1, Natural Gas and Propane Installation Code

3 feet (.9m) above if within 10 feet

(3m) horizontally

* 7 feet (2.1m)

*12 inches (305mm)

FIGURE 28

Operable

Fixed

Closed

AREA WHERE TERMINAL IS NOT PERMITTED

Canadian Installations

12 inches (305mm) or 12 in. 305mm)

above average snow accumulation.

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

* 12"

* Equal to or greater than soffit depth* Equal to or greater than soffit depth

* No minimum to outside corner

* 3 feet (.9m)

3 feet (.9m) within a height 15 feet (4.5m)

above the meter / regulator assembly

3 feet (.9m)

6 inches (152mm) for appliances <10,000

Btuh (3kw), 12 inches (305mm) for

appliances > 10,000 Btuh (3kw) and

<100,000 Btuh (30kw), 36 inches (.9m)

for appliances > 100,000 Btuh (30kw)

6 feet (1.8m)

7 feet (2.1m)

12 inches (305mm)

Page 26

Page 27

Details of Intake and Exhaust Piping Terminations for Direct Vent Installations

NOTE − In Direct Vent installations, combustion air is taken from outdoors and flue gases are discharged to outdoors.

Intake and exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 29 through 40 show typical terminations.

1. Exhaust and intake exits must be in same pressure zone. Do not exit one through the roof and one on the side. Also, do not exit the intake on one side and the exhaust on another side of the house or structure.

2. Intake and exhaust pipes should be placed as close together as possible at termination end (refer to illustrations). Maximum separation is 3" (76mm) on roof terminations and 6" (152mm) on side wall terminations.

3. On roof terminations, the intake piping should terminate straight down using two 90° elbows (See figure

29).

4. Exhaust piping must terminate straight out or up as shown. A reducer may be required on the exhaust piping at the point where it exits the structure to improve the velocity of exhaust away from the intake piping. See table 11.

TABLE 11

EXHAUST PIPE TERMINATION SIZE REDUCTION

ML193UH

MODEL

*045 and 070

*090 2" (51mm)

110 2" (51mm)

135

Exhaust Pipe Size

2" (51mm), 2−1/2" (64mm),

3" (76mm)

Termination

Pipe Size

1−1/2" (38mm)

2" (51mm)

*ML193UH−045, −070 and −090 units with the flush mount termination must use the 1 1/2"accelerator supplied with the kit.

NOTE − Care must be taken to avoid recirculation of exhaust back into intake pipe.

Inches(mm)

8" (203mm) MIN

12" (305mm) ABOVE

AVERAGE SNOW

ACCUMULATION

3" (76mm) OR

2" (51mm) PVC

PROVIDE SUPPORT

FOR INTAKE AND

EXHAUST LINES

DIRECT VENT ROOF TERMINATION KIT

3"(76mm) MAX.

(15F75 or 44J41)

SIZE TERMINATION

PIPE PER TABLE 11.

UNCONDITIONED

ATTIC SPACE

1/2" (13mm) FOAM

INSULATION IN

UNCONDITIONED

SPACE

FIGURE 29

FIELD SUPPLIED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

NOTE − FIELD PROVIDED

REDUCER MAY BE

REQUIRED TO ADAPT

LARGER VENT PIPE SIZE

TO TERMINATION

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

SIZE TERMINATION

PER TABLE 11

* WALL

SUPPORT

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

STRAIGHT

APPPLICATION

EXTENDED

APPLICATION

See venting table 10 for maximum venting lengths with this arrangement.

* Use wall support every 24" (610 mm). Use two wall supports if extension is greater than 24" (610 mm) but less than 48" (1219 mm). NOTE − One wall support must be 6" (152 mm) from top of each pipe (intake and exhaust)

A−Minimum clearance

above grade or average

snow accumulation

B−Maximum horizontal separation between

intake and exhaust

C−Minimum from

end of exhaust to

inlet of intake

D−Maximum exhaust

pipe length

E−Maximum wall support

distance from top of each

pipe (intake/exhaust)

2" (51mm)

Vent Pipe

12" (508MM) 12" (508MM)

6" (152MM) 6" (152MM)

8" (203MM) 8" (203MM)

12" (305MM) 20" (508MM)

6" (152MM) 6" (152MM)

3" (76mm)

Vent Pipe

FIGURE 30

Page 27

Page 28

FIELD SUPPLIED WALL TERMINATION OR

(15F74) WALL RING TERMINATION KIT

With INTAKE ELBOW

NOTE − FIELD PROVIDED

REDUCER MAY BE

REQUIRED TO ADAPT

LARGER VENT PIPE SIZE

TO TERMINATION

1/2" (13mm) ARMAFLEX

INSULATION IN UN-

CONDITIONED SPACE

SIZE TERMINATION

1/2" (13mm) ARMAFLEX INSULATION

IN UNCONDITIONED SPACE

* WALL

SUPPORT

PER TABLE 11

STRAIGHT

APPPLICATION

5. On field supplied terminations for side wall exit, exhaust piping may extend a maximum of 12 inches (305mm) for 2" PVC and 20 inches (508mm) for 3" (76mm) PVC beyond the outside wall. Intake piping should be as short as possible. See figures 30 and 31.

6. On field supplied terminations, a minimum distance between the end of the exhaust pipe and the end of the intake pipe without a termination elbow is 8" and a minimum distance of 6" with a termination elbow. See figures 30 and 31.

7. If intake and exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, piping must be supported every 24" (610mm) as shown in figures 30 and 31. In addition, close coupled wall termination kits must be extended for use in this application. See figures 38 and 39. When exhaust and intake piping must be run up an outside wall, the exhaust piping must be terminated with pipe sized per table 11.The intake piping may be equipped with a 90° elbow turndown. Using turndown will add 5 feet (1.5m) to the equivalent length of the pipe.

8. A multiple furnace installation may use a group of up to four terminations assembled together horizontally, as shown in figure 35.

See venting table 10 for maximum venting lengths with this arrangement.

2" (51mm)

Vent Pipe

A−Minimum clearance

above grade or average

snow accumulation

B−Maximum horizontal

separation between

intake and exhaust

C−Minimum from

end of exhaust to

inlet of intake

D−Maximum exhaust

pipe length

E−Maximum wall support

distance from top of each

pipe (intake/exhaust)

12" (508MM) 12" (508MM)

6" (152MM) 6" (152MM)

6" (152MM)

12" (305MM) 20" (508MM)

6" (152MM) 6" (152MM)

EXTENDED

APPLICATION

3" (76mm)

Vent Pipe

6" (152MM)

2" EXTENSION FOR 2" PVC PIPE 1" EXTENSION FOR 3" PVC PIPE

FURNACE

INTAKE PIPE

FLUSH−MOUNT SIDE WALL TERMINATION

4’’

GLUE EXHAUST

END FLUSH INTO

TERMINATION

FLAT SIDE

1−1/2" ACCELERATOR

(all −45, −070 and −090 units)

51W11

FIGURE 32

FURNACE EXHAUST

PIPE

FIGURE 31

Page 28

Page 29

EXHAUST

12” (305mm)

Minimum

Above Average

Snow

Accumulation

CLAMP

VENT

1 1/2" (38mm) accelerator

provided on 71M80 & 44W92

kits for ML193UH045P24B,

070P24B & 070P36B

INTAKE

AIR

FLASHING

(Not Furnished)

SHEET METAL STRAP

(Clamp and sheet metal strap must be field installed to support the weight of the termination kit.)

FIELD−PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT LARGER VENT

PIPE SIZE TO TERMINATION

Front View

INTAKE

AIR

Top View

1/2" (13mm) Foam Insulation

in Unconditioned Space

FIELD−

PROVIDED

REDUCER MAY

BE REQUIRED

TO ADAPT

LARGER VENT

PIPE SIZE TO

TERMINATION

EXHAUST VENT

SIZE

TERMINATION

PIPE PER

TABLE 11.

EXHAUST VENT

INTAKE AIR

6 (152mm) MIN.

DIRECT VENT CONCENTRIC ROOFTOP TERMINATION

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

FIGURE 33

FIELD−PROVIDED

REDUCER MAY BE REQUIRED

TO ADAPT LARGER VENT

PIPE SIZE TO TERMINATION

OUTSIDE

WALL

EXHAUST

VENT

INTAKE

AIR

CLAMP

(Not Furnished)

DIRECT VENT CONCENTRIC WALL TERMINATION

71M80, 69M29 or 60L46 (US)

41W92 or 41W93 (Canada)

1−1/2" (38mm) accelerator

provided on 71M80 & 44W92

kits for ML193UH045P24B,

070P24B & 070P36B

INTAKE

AIR

12" (305mm) Min.

above grade or

average snow accumulation.

INTAKE

GRADE

FIGURE 34

EXHAUST

VENT

INTAKE

AIR

Inches (mm)

(127mm)

18" MAX.

(457mm)

EXHAUST VENT

INTAKE

AIR

12"

(305mm)

5−1/2"

(140mm)

Front View

12" (305mm) Min.

above grade or

average snow accumulation.

EXHAUST

VENT

DIRECT VENT WALL TERMINATION KIT

(30G28 or 81J20)

FIGURE 36

Front View

INTAKE

AIR

Top View

1/2" (13mm) Foam Insulation

in Unconditioned Space

FIELD−

PROVIDED

REDUCER MAY

BE REQUIRED

TO ADAPT

LARGER VENT

PIPE SIZE TO

TERMINATION

DIRECT VENT WALL TERMINATION KIT

(22G44 or 44J40)

FIGURE 37

OUTSIDE WALL

EXHAUST VENT

SIZE

TERMINATION

PIPE PER

TABLE 11.

EXHAUST VENT

INTAKE AIR

8" (206mm) MIN.

OUTSIDE WALL

optional intake elbow

Side View

OPTIONAL VENT TERMINATION FOR MULTIPLE UNIT

INSTALLATION OF DIRECT VENT WALL TERMINATION KIT

(22G44, 44J40, 30G28 or 81J20)

FIGURE 35

Page 29

Page 30

WALL TERMINATION KITS (CLOSE−COUPLE)

EXTENDED VENT FOR GRADE CLEARANCE

If intake and exhaust pipe is less than 12 in. (305 mm) above snow accumulation or other obstructions, field− fabricated piping must be installed.

8” (203 mm) Min. for 2” (51 mm) & 3” (76 mm) DIA. pipe

WALL SUPPORT*

6” (152 mm)

Maximum

INTAKE

AIR

between the end of the exhaust pipe and intake pipe 12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

8” (203 mm) Min.

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

2 inch (51 mm) 22G44 (US)

3 inch (76 mm) 44J40 (US)

EXHAUST

AIR

INTAKE

5” (127 mm)

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

GRADE

*Use wall support every 24" (610). Use two supports if

extension is greater than 24" but less than 48".

AIR

REDUCER MAY BE REQUIRED TO ADAPT

LARGER VENT PIPE SIZE TO TERMINATION

FIELD−PROVIDED

12”

(305 mm)

1/2” (13 mm)

FOAM INSULATION

(Field−Furnished)

EXHAUST

AIR

12” (305 mm) Minimum

5−1/2”

(140 mm)

Above Grade or Average

Snow Accumulation

GRADE

WALL TERMINATION KITS (CLOSE−COUPLE)

EXTENDED VENT FOR GRADE CLEARANCE

2 inch (51 mm) 30G28 (WTK Canada) 3 inch (76 mm) 81J20 (WTK Canada)

See Installation Instructions for additional information.

If intake and exhaust pipe is less than 12 in. (305 mm) above snow accumulation or other obstructions, field− fabricated piping must be installed.

WALL SUPPORT*

6” (152 mm)

Maximum

INTAKE

AIR

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

6” (152 mm)

Minimum

6” (152 mm)

Minimum

FIGURE 38

EXHAUST

AIR

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

GRADE

REDUCER MAY BE REQUIRED TO ADAPT

LARGER VENT PIPE SIZE TO TERMINATION

FIELD−PROVIDED

12”

(305 mm)

INTAKE

AIR

5” (127 mm)

5−1/2”

(140 mm)

1/2” (13 mm)

FOAM INSULATION

(Field−Furnished)

EXHAUST

AIR

12” (305 mm) Minimum

Above Grade or Average

Snow Accumulation

GRADE

12” (305 mm) Max. for 2” (51 mm) Dia. Exhaust 20” (508 mm) Max. for 3” (76 mm) Dia. Exhaust

FIGURE 39

Page 30

*Use wall support every 24" (610). Use two supports if

extension is greater than 24" but less than 48".

Page 31

ML193UH DIRECT VENT APPLICATION

USING EXISTING CHIMNEY

STRAIGHT−CUT OR

3"−8"

(76mm−203mm)

8" − 12"

(203mm − 305mm)

Minimum 12" (305MM)

above chimney top

plate or average snow

accumulation

*SIZE TERMINATION PIPE PER TABLE 11.

NOTE − Do not discharge exhaust gases directly into any chimney or vent stack. If vertical discharge through an existing unused chimney or stack is required, insert piping inside chimney until the pipe open end is above top of chimney and terminate as illustrated. In any exterior portion of chimney, the exhaust vent must be insulated.

INTAKE PIPE

INSULATION (optional)

SHEET

METAL TOP

PLATE

INSULATE TO FORM

SEAL

ANGLE−CUT IN DIRECTION

OF ROOF SLOPE *

EXHAUST VENT

1/2" (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

3" − 8" (76mm− 203mm)

ALTERNATE

INTAKE PIPE

EXTERIOR

PORTION OF

CHIMNEY

FIGURE 40 Details of Exhaust Piping Terminations for Non-Direct Vent Applications

Exhaust pipes may be routed either horizontally through an outside wall or vertically through the roof. In attic or closet installations, vertical termination through the roof is preferred. Figures 41 through 44 show typical terminations.

1. Exhaust piping must terminate straight out or up as

shown. The termination pipe must be sized as listed in table 11.The specified pipe size ensures proper velocity required to move the exhaust gases away from the building.

2. On field supplied terminations for side wall exit, ex-

haust piping may extend a maximum of 12 inches (305mm) for 2" PVC and 20 inches (508mm) for 3" (76mm) PVC beyond the outside wall. See figure 42.

SIZE TERMINATION

12" (305mm) ABOVE AVE.

SNOW

ACCUMULATION

1/2" (13mm) FOAM

INSULATION

PIPE PER TABLE

11.

12" (305mm) MAX. for 2" (51mm)

1/2" (13mm) ARMAFLEX

INSULATION IN

UNCONDITIONED SPACE

FIELD−PROVIDED

REDUCER MAY

BE REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE

TO TERMINATION

SIZE TERMINATION

PIPE PER TABLE 11.

20" (508mm) MAX. for 3" (76mm)

1/2" (13mm)

ARMAFLEX

INSULATION

PVC REDUCER

12" MIN. (305mm)

Above Grade or

average snow

accumulation

NON−DIRECT VENT FIELD SUPPLIED WALL TERMINATION OR

(15F74) WALL TERMINATION KIT

FIGURE 42

3. If exhaust piping must be run up a side wall to position above snow accumulation or other obstructions, piping must be supported every 24 inches (610mm) as shown in figure 43. When exhaust piping must be run up an outside wall, any reduction in exhaust pipe size must be done after the final elbow.

12" (305mm) MAX. for 2" (51mm)

UNCONDITIONED

SPACE

*WALL SUPPORT

FIELD−PROVIDED

REDUCER MAY BE

REQUIRED TO

ADAPT LARGER

VENT PIPE SIZE TO

TERMINATION

1/2" (13mm) FOAM

INSULATION IN

UNCONDITIONED

SPACE

6" (152mm)

Max

OUTSIDE WALL

20" (508mm) MAX. for 3" (76mm)

SIZE TERMINATION PIPE PER TABLE 11.

12" (305mm)

ABOVE GRADE OR

AVERAGE SNOW

ACCUMULATION

1/2" (13mm) FOAM

INSULATION

NON−DIRECT VENT FIELD SUPPLIED WALL TERMINATION

EXTENDED OR (15F74) WALL TERMINATION VENT PIPE

*Use wall support every 24" (610). Use two supports if extension is

greater than 24" but less than 48".

EXTENDED

FIGURE 43

3" (76mm) OR

2" (51mm) PVC

PROVIDE SUPPORT

FOR EXHAUST LINES

NON−DIRECT VENT ROOF TERMINATION KIT

(15F75 or 44J41)

FIGURE 41

UNCONDITIONED

ATTIC SPACE

Page 31

Page 32

ML193UH NON−DIRECT VENT APPLICATION

USING EXISTING CHIMNEY

SIZE TERMINATION

PIPE PER TABLE 11.

Minimum 12" (305MM)

above chimney top

plate or average snow

accumulation

SHEET

METAL TOP

PLATE

INSULATE

TO FORM

SEAL

STRAIGHT−CUT OR

ANGLE−CUT IN DIRECTION

OF ROOF SLOPE

EXHAUST VENT

1/2" (13mm)

WEATHERPROOF

INSULATION

SHOULDER OF FITTINGS

PROVIDE SUPPORT

OF PIPE ON TOP PLATE

EXTERIOR

PORTION OF

CHIMNEY

FIGURE 44

Condensate Piping

This unit is designed for either right- or left-side exit of condensate piping in upflow applications. In horizontal applications, the condensate trap must extend below the unit. An 8" service clearance is required for the condensate trap. Refer to figure 45 for condensate trap locations.

NOTE − If necessary the condensate trap may be installed up to 5´ away from the furnace. Use PVC pipe to connect trap to furnace condensate outlet. Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

CONDENSATE TRAP AND PLUG LOCATIONS

(Unit shown in upflow position)

Trap

(same on

right side)

1−1/2 in.

1 − Determine which side condensate piping will exit the

unit, location of trap, field−provided fittings and length of PVC pipe required to reach available drain.

2 − Remove plug (figure 45) from the cold end header box

at the appropriate location on the side of the unit. Install field−provided 1/2 NPT male fitting into cold end header box. Use Teflon tape or appropriate pipe dope.

3 − Install the cap over the clean out opening at the base of

the trap. Secure with clamp. See figure 49.

4 − Install drain trap using appropriate PVC fittings, glue

all joints. Glue the provided drain trap as shown in figure 49. Route the condensate line to an open drain.

Condensate line must maintain a 1/4" downward slope from the furnace to the drain.

CAUTION

Do not use copper tubing or existing copper conden- sate lines for drain line.

5 − If unit will be started immediately upon completion of

installation, prime trap per procedure outlined in Unit Start−Up section.

Condensate line must slope downward away from the trap to drain. If drain level is above condensate trap, condensate pump must be used. Condensate drain line should be routed within the conditioned space to avoid freezing of condensate and blockage of drain line. If this is not possible, a heat cable kit may be used on the condensate trap and line. Heating cable kit is available from Lennox in various lengths; 6 ft. (1.8m) − kit no. 26K68; 24 ft. (7.3m) − kit no. 26K69; and 50 ft. (15.2m) − kit no. 26K70.

CONDENSATE TRAP LOCATIONS

(Unit shown in upflow position with remote trap)

Field−Provided Vent

Min. 1" Above Condensate

Drain Connection

(same on left side)

NOTE − In upflow applications where side return air filter is installed on same side as the condensate trap, filter rack must be installed beyond condensate trap or trap must be re−located to avoid interference.

FIGURE 45

Plug

1" Min.

5’ max.

*PVC Pipe Only

Trap can be installed a

maximum 5’ from furnace.

To Drain

*Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

FIGURE 46

Page 32

Page 33

CAUTION

A separate drain line must be run to the drain from the condensate trap. DO NOT connect the condensate trap drain into the drain line from the evaporator coil.

ML193UH with Cooling Coil

Condensate trap and

evaporator coil must

drain separately as

shown.

Field−Provided

Vent

Drain

FIGURE 47

(Unit shown in horizontal right−hand discharge position)

Field−Provided Vent

Must Not Interfere With

Service To The Unit

to drain

CONDENSATE TRAP LOCATIONS

4−1/2"

Min.

5’ max.

*PVC Pipe Only

*Piping from furnace must slope down a minimum of 1/4" per ft. toward trap.

FIGURE 48

Page 33

Page 34

TRAP / DRAIN ASSEMBLY USING 1/2" PVC OR 3/4" PVC

OPTIONAL Condensate Drain Connection

Adapter 1/2 inch slip X

1/2 inch mpt (Not Furnished)

90° Street Elbow

1/2 inch PVC

(Not Furnished)

1/2 inch mpt (Not Furnished)

1 (25) Minimum

Above Top of Condensate Drain

Connection In Unit

Adapter 1/2 inch slip X

Vent

5 Feet

Maximum

Condensate Drain

Connection In Unit

Condensate Drain

Connection In Unit

Drain Assembly for 1/2 inch Drain Pipe

90° Street Elbow

1/2 inch PVC

(Not Furnished)

Drain

Drain Assembly for 3/4 inch Drain Pipe

90° Elbow

3/4 inch PVC

(Not Furnished)

Drain

OPTIONAL Drain Piping

1/2 inch PVC

(Not Furnished)

Drain

90° Elbow

3/4 inch PVC

(Not Furnished)

Coupling 3/4 inch slip X slip

Drain

(Not Furnished)

90° Elbow 1/2 inch PVC

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

1/2 inch PVC Pipe

(Not Furnished)

90° Elbow

1/2 inch PVC Pipe

(Not Furnished)

Coupling 1/2 inch slip X slip

(Not Furnished)

Drain Trap

Assembly

(Furnished)

Drain Trap

Clean Out

Drain Trap Assembly with 1/2 inch Piping

1 inch (25mm) Minimum Above Top of

Condensate Drain Connection In Unit

Drain Trap Assembly

(Furnished)

(178)

Drain

Vent

Condensate Drain

Connection In Unit

FIGURE 49

Page 34

Drain Trap Assembly with 3/4 inch Piping

1 inch (25mm) Minimum Above Top of

Condensate Drain Connection In Unit

Vent

Condensate Drain

Connection In Unit

Drain

Page 35

III−START-UP A−Preliminary and Seasonal Checks

1 − Inspect electrical wiring, both field and factory installed

for loose connections. Tighten as required.

2 − Check voltage at disconnect switch. Voltage must be with-

in range listed on the nameplate. If not, consult the po wer company and have voltage condition corrected before starting unit.

3 − Inspect condition of condensate traps and drain as-

sembly. Disassemble and clean seasonally.

B−Heating Start-Up

BEFORE LIGHTING the unit, smell all around the fur-

nace area for gas. Be sure to smell next to the floor because some gas is heavier than air and will settle on the floor.

The gas valve on the ML193UH is equipped with a gas control switch. Use only your hand to move the switch. Never use tools. If the the switch will not move by hand, replace the valve. Do not try to repair it. Force or attempted repair may result in a fire or explosion.

Placing the furnace into operation:

ML193UH units are equipped with a SureLight ignition system. Do not attempt to manually light burners on this furnace. Each time the thermostat calls for heat, the burners will automatically light The ignitor does not get hot when there is no call for heat on units with SureLightt ignition system.

Priming Condensate Trap

The condensate trap should be primed with water prior to start−up to ensure proper condensate drainage. Either pour 10 fl. oz. (300 ml) of water into the trap, or follow these steps to prime the trap:

1 − Follow the lighting instructions to place the unit into op-

eration.

2 − Set the thermostat to initiate a heating demand.

3 − Allow the burners to fire for approximately 3 minutes. 4 − Adjust the thermostat to deactivate the heating de-

mand.

5 − Wait for the combustion air inducer to stop. Set the

thermostat to initiate a heating demand and again allow the burners to fire for approximately 3 minutes.

6 − Adjust the thermostat to deactivate the heating de-

mand and again wait for the combustion air inducer to stop. At this point, the trap should be primed with sufficient water to ensure proper condensate drain operation.

WARNING

If you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or death.

Gas Valve Operation (Figure 50)

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. See figure 50. 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 instructions. If you do not smell gas go to next step.

8 − Move gas valve switch to ON. See figure 50.

MANIFOLD

PRESSURE

ADJUSTMENT

SCREW

INLET

PRESSURE

PORT

GAS VALVE SHOWN IN ON POSITION

MANIFOLD

PRESSURE

OUTLET

FIGURE 50

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 your service technician or 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.

5 − Replace the upper access panel.

Failure To Operate

If the unit fails to operate, check the following: 1 − Is the thermostat calling for heat? 2 − Are access panels securely in place? 3 − Is the main disconnect switch closed? 4 − Is there a blown fuse or tripped breaker? 5 − Is the filter dirty or plugged? Dirty or plugged filters will

cause the limit control to shut the unit off. 6 − Is gas turned on at the meter? 7 − Is the manual main shut-off valve open? 8 − Is the internal manual shut-off valve open? 9 − Is the unit ignition system in lockout? If the unit locks out

again, inspect the unit for blockages.

Page 35

Page 36

IV−HEATING SYSTEM SERVICE CHECKS

D−Testing Gas Supply Pressure

A−C.S.A. Certification

All units are C.S.A. design certified without modifications. Refer to the ML193UH Operation and Installation Instruction Manual Information.

B−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. The flexible connector can then be added between the black iron pipe and the gas supply line.

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

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.

When pressure testing gas lines, the gas valve must be disconnected and isolated. Gas valves can be damaged if subjected to more than 0.5psig (14" W.C.). See figure 51.

MANUAL MAIN SHUT−OFF

VALVE WILL NOT HOLD

NORMAL TEST PRESSURE

1/8" N.P.T. PLUGGED TAP

CAP

FIGURE 51

When checking piping connections for gas leaks, use preferred means. Kitchen detergents can cause harmful corrosion 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.

WARNING

Do not use matches, candles, flame or any other source of ignition to check for gas leaks.

FURNACE

ISOLATE

GAS VALVE

Gas Flow (Approximate)

TABLE 12

GAS METER CLOCKING CHART

Seconds for One Revolution

ML193

Unit

−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 checking gas flow. Determine time in seconds for two revolutions of gas through the meter. (Two revolutions assures a more accurate time.) Divide by two and compare to time in table 12 below. If manifold pressure matches table 13 and rate is incorrect, check gas orifices for proper size and restriction. Remove temporary gas meter if installed.

NOTE − To obtain accurate reading, shut off all other gas appliances connected to meter.

Supply Pressure Measurement

When testing supply gas pressure, use the 1/8" N.P.T. plugged tap or pressure post located on the gas valve to facilitate test gauge connection. See figure 50. Check gas line pressure with unit firing at maximum rate. Low pressure may result in erratic operation or underfire. High pressure can result in permanent damage to gas valve or overfire.

On multiple unit installations, each unit should be checked separately, with and without units operating. Supply pressure must fall within range listed in table 13.

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 manometer to measure manifold pressure.

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

13.

NOTE − Shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to remove barbed fitting and replace threaded plug.

Natural LP

1 cu ft

Dial

2 cu ft

Dial

1 cu ft

Dial

2 cu ft

DIAL

Page 36

Page 37

TABLE 13

Supply Line and Manifold Pressure (inches w.c.)

Unit Fuel

All Nat. Gas 3.5 4.5 − 10.4

All L.P. Gas 10.0 11.0 − 13.0

Manifold Pres-

sure

Line

Pressure

NOTE − A natural to L.P. propane gas changeover kit is necessary to convert this unit. Refer to the changeover kit installation instruction for the conversion procedure.

E−Proper Combustion

Furnace should operate minimum 15 minutes with correct manifold pressure and gas flow rate before checking combustion. Take combustion sample beyond the flue outlet and compare to the tables below.

TABLE 14

ML193

Unit

−045

−070

−090

−110

−135

The maximum carbon monoxide reading should not exceed 50 ppm.

CO2%

For Nat

CO2%

7.2 − 7.9 8.6 − 9.3

For L.P.

F−High Altitude

NOTE − In Canada, certification for installations at elevations over 4500 feet (1372 m) is the jurisdiction of local authorities.

ML193UH units require no manifold pressure adjustments for operation at altitudes up to 10,000 feet (3048 m) above sea level. Units installed at altitude of 4501 − 10,000 feet (1373 to 3048m) require a pressure switch change which can be ordered separately. Table 15 lists conversion kit and pressure switch requirements at varying altitudes.

The combustion air pressure switch is factory−set and requires no adjustment.

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.

TABLE 15

Conversion Kit and Pressure Switch Requirements at Varying Altitudes

High Altitude

Natural Burner

Orifice Kit

7501 − 10,000 ft

(2286 − 3038m)

LP/Propane to

Natural

0 − 7500 ft

(0 − 2286m)

High Altitude Pressure Switch

4501 − 7500 ft

(1373 − 2286m)

7501 −10,000 ft

(2286 − 3048m)

ML193

Unit

Natural to

LP/Propane

0 − 7500 ft

(0 − 2286m)

−045

−070

−090

*69W73 73W37 *73W81 74W90 74W91

−110

−135

* Conversion requires installation of a gas valve manifold spring which is provided with the gas conversion kit. Pressure switch is factory set. No adjustment necessary. All models use the factory−installed pressure switch from 0−4500 feet (0−1370 m).

Page 37

Page 38

G−Flame Signal

A transducer (Part #78H5401 available from Lennox Repair Parts) is required to measure flame signal if meter used will not read a low micro amp signal. Seefigure52. The transducer converts microamps to volts on a 1:1 conversion. Flame signal is shown in table 16. A digital readout meter must be used . The transducer plugs into most meters.

TABLE 16

Normal Flame Signal

Low Flame Signal

 1.50 Microamps

 1.40 Microamps

Drop Out Signal = 0.50 Microamps

To Measure Flame Signal:

1 − Set the volt meter to the DC voltage scale. Insert

transducer into the VDC and common inputs. Observe correct polarities. Failure to do so results in

negative (−) values. 2 − Turn off supply voltage to control. 3 − Disconnect integrated control flame sensor wire from

the flame sensor. 4 − Connect (−) lead of the transducer to flame sensor. 5 − Connect (+) lead of transducer to the integrated control

sensor wire. 6 − Turn supply voltage on and close thermostat contacts to

cycle system. 7 − When main burners are in operation for two minutes, take

reading. Remember 1 DC volt = 1 DC microamp.

NOTE−MUST USE DIGITAL METER

SET DIAL TO

MEASURE VDC

TRANSDUCER PART #78H5401

RED COLLAR

INDICATES

POSITIVE

LEAD

(+) TO

INTE-

GRATED

CONTROL

SENSOR

WIRE

(+)

(−)

(−) TO

FLAME

SENSOR

FIGURE 52

V−TYPICAL OPERATING CHARACTERISTICS

A−Blower Operation and Adjustment

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

Temperature rise depends on unit input, 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.

To Measure Temperature Rise:

1 − Place plenum thermometers in the supply and return air

plenums. Locate supply air thermometer in the first horizontal run of the plenum where it will not pick up radiant heat from the heat exchanger.

2 − Set thermostat for heat call.

3 − After plenum thermometers have reached their high-

est and steadiest readings, subtract the two readings. The difference should be in the range listed on the unit rating plate. If the temperature is too low, decrease blower speed. If temperature is too high, first check the firing rate. Provided the firing rate is acceptable, in-

crease blower speed to reduce temperature. To change existing heat tap, turn off power then switch out speed tap with tap connected to "PARK" . See unit diagram for blower motor tap colors for each speed.

C−External Static Pressure

1 − Tap locations shown in figure 53.

2 − Punch a 1/4" diameter hole

STATIC PRESSURE TEST

in supply and return air ple-

nums. Insert manometer

hose flush with inside edge

of hole or insulation. Seal

around the hose with perma-

−

gum. Connect the zero end

of the manometer to the dis-

FIGURE 53

charge (supply) side of the system. On ducted sys-

tems, connect the other end of manometer to the return

duct as above.

3 − With only the blower motor running and the evaporator

coil dry, observe the manometer reading. Adjust blow-

er motor speed to deliver the air desired according to

the job requirements.

4 − External static pressure drop must not be more than

0.5" W.C. in the heating mode and must not exceed

0.6" W.C in the cooling mode.

5 − Seal the hole when the check is complete.

Page 38

Page 39

VI−MAINTENANCE

WARNING

ELECTRICAL SHOCK, FIRE,

OR EXPLOSION HAZARD.

Failure to follow safety warnings exactly could result in dangerous operation, serious injury, death or property damage. Improper servicing could result in dangerous operation, serious injury, death, or property damage. Before servicing, disconnect all electrical power to furnace. When servicing controls, label all wires prior to disconnecting. Take care to reconnect wires correctly. Verify proper operation after servicing.

At the beginning of each heating season, system should be checked as follows by a qualified service technician:

Blower

Check the blower wheel for debris and clean if necessary. The blower motors are prelubricated for extended bearing life. No further lubrication is needed.

WARNING

The blower access panel must be securely in place when the blower and burners are operating. Gas fumes, which could contain carbon monoxide, can be drawn into living space resulting in personal injury or death.

Filters

All air filters are installed external to the unit. Filters should be inspected monthly. Clean or replace the filters when necessary to ensure proper furnace operation. Table 17 lists recommended filter sizes.

TABLE 17

Furnace

Cabinet Width

17−1/2" 16 X 25 X 1 (1) 16 X 25 X 1 (1)

21" 16 X 25 X 1 (1) 20 X 25 X 1 (1)

24−1/2" 16 X 25 X 1 (2) 24 X 25 X 1 (1)

Exhaust and air intake pipes

Check the exhaust and air intake pipes and all connections for tightness and to make sure there is no blockage.

NOTE − After any heavy snow, ice or frozen fog event the furnace vent pipes may become restricted. Always check the vent system and remove any snow or ice that may be obstructing the plastic intake or exhaust pipes.

Electrical

1 − Check all wiring for loose connections. 2 − Check for the correct voltage at the furnace (furnace

operating). Correct voltage is 120VAC + 10%

Side Return Bottom Return

Filter Size

3 − Check amp−draw on the blower motor with blower ac-

cess panel in place. Motor Nameplate__________Actual__________

Winterizing and Condensate Trap Care

1 − Turn off power to the furnace.

2 − Have a shallow pan ready to empty condensate water.

3 − Remove the clean out cap from the condensate trap

and empty water. Inspect the trap then reinstall the clean out cap.

Cleaning Heat Exchanger

If cleaning the heat exchanger becomes necessary, follow the below procedures and refer to figure 1 when disassembling unit. Use papers or protective covering in front of furnace while removing heat exchanger assembly.

1 − Turn off electrical and gas supplies to the furnace. 2 − Remove the burner access panel. 3 − Mark all gas valve wires and disconnect them from

valve. 4 − Remove gas supply line connected to gas valve. 5 − Remove sensor wire from flame sensor. Disconnect

2-pin plug from the ignitor. 6 − Disconnect wires from flame roll−out switches. 7 − Remove four burner assembly screws at the vestibule

panel and remove gas valve /manifold and burner box

as a single unit.

NOTE − If necessary, clean burners at this time. Follow

procedures outlined in Burner Cleaning section.

9 − Remove the clean−out cap on trap and drain. Replace

cap. 10 − Disconnect condensate drain line from the conden-

sate trap. Remove condensate trap (it may be neces-

sary to cut drain pipe). Remove the 1/2" NPT fitting

from the cold end header box. Disconnect drain tubes

from cold end header collector box. 11 − Disconnect condensate drain tubes from flue collar.

Remove screws that secures flue collar in place. Re-

move flue collar. It may be necessary to cut the exiting

exhaust pipe for removal of the fitting. 12 − Loosen two clamps from flexible no−hub exhaust col-

lar. 13 − Disconnect the 2-pin plug from the combustion air in-

ducer. Remove screws which secure combustion air

inducer to collector box. Remove combustion air in-

ducer assembly. Remove ground wire. 14 − Mark and disconnect all combustion air pressure tub-

ing from cold end header collector box. 15 − Mark and remove wires from pressure switch. Re-

move pressure switch. Keep tubing attached to pres-

sure switch. 16 − Remove electrical junction box from the side of the fur-

nace. 17 − Remove blower access panel. 18 − Mark and disconnect any remaining wiring to heating

compartment components. Disengage strain relief

bushing and pull wiring and bushing through the hole in

the blower deck. 19 − Remove the primary limit from the vestibule panel.

Page 39

Page 40

20 − Remove top cap screws to allow top cap to be tilted up-

ward to allow clearance for removing heat exchanger.

21 − Remove two screws from the front cabinet flange at

the blower deck. Spread cabinet sides slightly to allow clearance for removal of heat exchanger.

22 − Remove screws along vestibule sides and bottom

which secure vestibule panel and heat exchanger assembly to cabinet. Remove two screws from blower rails which secure bottom heat exchanger flange. Remove heat exchanger from furnace cabinet.

23 − Back wash heat exchanger with soapy water solution

or steam. If steam is used it must be below 275°F

(135°C) .

24 − Thoroughly rinse and drain the heat exchanger. Soap

solutions can be corrosive. Take care to rinse entire assembly.

25 − Reinstall heat exchanger into cabinet making sure that

the rear baffle of the heat exchanger assembly is nested under the support located at the rear of the cabinet. Remove the indoor blower to view this area through the blower opening.

26 − Re-secure the supporting screws along the vestibule

sides.

27 − Reinstall blower assembly and reinstall two screws

through rails.

28 − Reinstall cabinet screws on front flange at blower

deck. 29 − Reinstall screws securing top cap. 30 − Reinstall the primary limit on the vestibule panel. 31 − Route heating component wiring through hole in blow-

er deck and reinsert strain relief bushing. 32 − Reinstall pressure switch and reconnect pressure

switch wiring. 33 − Carefully connect combustion air pressure switch

hosing from pressure switch to proper stubs on cold

end header collector box. 34 − Reinstall 1/2" NPT (if removed) in the cold end header

box. Reconnect drain tubing to collector box. 35 − Reinstall condensate trap pipe. Reconnect conden-

sate drain line to the condensate trap. 36 − Reinstall electrical junction box. 37− Reinstall the combustion air inducer and flexible no

hub connector. Reconnect the 2−pin plug to the wire

harness. 39 − Reconnect drain tubes between flue collar and cold

end header box. 40 − Secure burner assembly to vestibule panel using four

existing screws. Burners are self aligning to center

of clam shells.

41 − Reconnect gas supply line to gas valve. 42 − Reconnect flame roll−out switch wires. 43 − Reconnect sensor wire and reconnect 2−pin plug from

ignitor. 44 − Reconnect wires to gas valve. 45 − Replace the blower compartment access panel. 46 − Refer to instruction on verifying gas and electrical con-

nections when re−establishing supplies. 47 − Follow lighting instructions to light and operate fur-

nace for 5 minutes to ensure that heat exchanger is

clean and dry and that furnace is operating properly. 48 − Replace heating compartment access panel.

Cleaning the Burner Assembly

1 − Turn off gas and electrical power to the furnace. Re-

move heating compartment access panel. 2 − Disconnect the gas supply line from the gas valve. 3 − Disconnect and label wires from gas valve. 4 − Disconnect ignitor wiring at 2 circuit plug. 5 − Disconnect and label wires from rollout switch. 6 − Disconnect and label flame sensor wire. 7 − Disconnect and label ground wire from burner/man-

ifold assembly. 8 − Remove four screws that secures burner/manifold as-

sembly to vestibule. Remove the assembly and make

note not to allow ignitor plate to dislodge from the as-

sembly. 9 − Gently clean the face of the burners using the soft

brush attachment on a vacuum cleaner. Visually in-

spect the inside of the burners and crossovers for any

blockage caused by foreign matter. Remove any

blockage 10 − Reinstall the burner/manifold assembly using the ex-

isting four screws. Burners are self aligning to cen-

ter of clam shells.

11 − Reconnect ground wire. 12 − Reconnect flame sensor wire. 13 − Reconnect rollout switch wires. 14 − Reconnect ignitor wires. 15 − Reconnect gas valve wires. 16 − Reconnect gas supply line to gas valve. 17 − Refer to instructions on verifying gas and electrical

connections when re−establishing supplies.

18 − Follow instructions to place furnace in operation. Run

furnace 5 minutes to ensure burners are clean and op-

erating correctly. 19 − Replace heating compartment access panel.

Page 40

Page 41

VII−WIRING DIAGRAM AND SEQUENCE OF OPERATION

1 − When there is a call for heat, W1 of the thermostat en-

ergizes W of the furnace control with 24VAC.

2 − S10 primary limit switch and S47 rollout switch are

closed. Call for heat can continue.

3 − The integrated control (A92) energizes combustion air

inducer B6. Combustion air inducer runs until S18 combustion air prove switch closes (switch must close within 2−1/2 minutes or control goes into 5 minute Watchguard Pressure Switch delay). Once S18 closes, a 15−second pre−purge follows.

4 − The integrated control (A92) energizes ignitor. A

20−second warm−up period begins.

5 − Gas valve opens for a 4−second trial for ignition

6 − Flame is sensed, gas valve remains open for the heat

call.

7 − After 45−second delay, the integrated control (A92) en-

ergizes indoor blower B3.

8 − When heat demand is satisfied, W1 of the indoor ther-

mostat de−energizes W of the integrated control which de−energizes the gas valve. Combustion air inducer B6 continues a 5−second post−purge period, and indoor blower B3 completes a selected OFF time delay.

Page 41

Page 42

Sequence of Operation Flow Chart

HEATING SEQUENCE OF OPERATION

NORMAL HEATING MODE

POWER ON

CONTROL SELF−CHECK OKAY?

YES

IS POLARITY CORRECT?

YES

IS THERE A PROPER GROUND?

YES

IS VOLTAGE

ABOVE 90 VOLTS?

YES

ROLLOUT SWITCH CLOSED?

YES

ABNORMAL HEATING MODE

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

(RESET CONTROL BY TURNING MAIN POWER OFF.)

CONTROL WILL NOT RESPOND TO A CALL FOR

HEATING UNTIL VOLTAGE RISES ABOVE 95 VOLTS.

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES

AND POWER IS RESET OR T’STAT IS INTERRUPTED

INDOOR BLOWER DELAY OFF.

LED #1 ON LED #2 ON

POLARITY REVERSED.

LED #1 −− FAST FLASH

LED #2 −− SLOW FLASH

IMPROPER GROUND. LED #1 −− ALTERNATING FAST FLASH LED #2 −− ALTERNATING FAST FLASH

LEDs SIGNAL FAST ALTERNATING FLASH.

INDOOR BLOWER ON.

LED #1 −− ON. LED #2 −− SLOW FLASH.

FOR MINIMUM OF 1 SECOND.

(Flame sensed without gas valve energized)

BURNER OFF?

YES

NORMAL OPERATION:

LED #1 −− SLOW FLASH LED #2 −− SLOW FLASH

YES

THERMOSTAT CALLS FOR HEAT:

LED #1 −− FAST FLASH LED #2 −− FAST FLASH

YES

PRIMARY LIMIT SWITCH. CLOSED?

YES

IS COMBUSTION AIR

PRESSURE SWITCH OPEN?

YES

IS COMBUSTION AIR INDUCER

ENERGIZED?

YES

HAS COMBUSTION AIR PRESSURE SWITCH CLOSED IN 2.5 MINUTES?

YES

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER ON HEATING SPEED.

PRESSURE SWITCH IS IN WATCHGUARD MODE.

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY.

LED #1 −− OFF. LED #2 −− SLOW FLASH.

IS 5-MINUTE RESET PERIOD COMPLETE?

LED #1 −− SLOW FLASH

LED #2 −− OFF

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER ON

LED #1 SLOW FLASH RATE

LED #2 −− ON

GAS VALVE OFF.

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY.

LED #1 OFF

LED #2 SLOW FLASH

(Sequence holds until pressure switch

opens or thermostat resets control.)

YES

CONTINUED NEXT PAGE

Page 42

Page 43

HEATING SEQUENCE CONTINUED

NORMAL HEATING MODE ABNORMAL HEATING MODE

15-SECOND COMBUSTION AIR INDUCER PREPURGE

INITIATED BY CLOSED PRESSURE SWITCH.

YES

IGNITOR WARM-UP −− 20 SECONDS.

YES

4-SECOND TRIAL FOR IGNITION.

GAS VALVE OPENS. IGNITOR ENERGIZED FOR

FIRST 3 SECONDS OF THE TRIAL.

YES

FLAME STABILIZATION PERIOD.

4 SECONDS

FLAME RECTIFICATION CURRENT

CHECK. CAN FLAME BE PROVEN WITHIN

4 SECONDS AFTER GAS VALVE OPENS?

(0.5 microamps)

YES

FLAME PRESENT?

YES

FLAME SIGNAL 1.5 MICROAMPS OR GREATER?

YES

INDOOR BLOWER ON

AFTER 30−SECOND DELAY

YES

PRIMARY AND SECONDARY LIMIT

SWITCHES CLOSED?

YES

IS VOLTAGE ABOVE 90 VOLTS?

YES

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

HAS CONTROL FAILED TO SENSE FLAME FOR

FIVE CONSECUTIVE TRIES DURING A SINGLE

WATCHGUARD MODE. GAS VALVE OFF.

LEDs SIGNAL WATCHGUARD FAILURE CODE.

IS 60-MINUTE RESET PERIOD COMPLETE?

(Does not affect operation of control)

LED #1 −− SLOW FLASH

LED #2 −− FAST FLASH

COMBUSTION AIR INDUCER DE−ENERGIZED.

INDOOR BLOWER ON UNTIL SWITCH CLOSES.

LED #1 −− SLOW FLASH. LED #2 −− ON.

HAS PRIMARY / SECONDARY

EXCEEDED 3 MINUTES?

INDOOR BLOWER OFF.

HEAT DEMAND?

COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH DELAY

HAS CONTROL RESET IGNITION

SEQUENCE FOUR TIMES?

LOW FLAME SIGNAL

GAS VALVE DE−ENERGIZED.

IS LIMIT SWITCH CLOSED?

YES

LIMIT RESET TIME

LEDS SIGNAL

LIMIT SWITCH WATCHGUARD MODE. GAS VALVE, COMB. AIR INDUCER AND INDOOR BLOW-

ER OFF. LEDs SIGNAL LIMIT

SWITCH OPEN UNTIL MAIN

YES

ALTERNATING

FAST FLASH UNTIL

VOLTAGE IS ABOVE

95 VOLTS, THEN

RESTARTS HEATING

SEQUENCE.

YES

POWER IS

INTERRUPTED OR

T’STAT IS CYCLED

OFF/ON FOR 1 SEC.

MINIMUM. 60−MINUTE

WATCHGUARD PE-

RIOD STARTS AT

TIME LIMIT CLOSES.

IS 60−MIN. PERIOD

COMPLETE?

ROLLOUT SWITCH CLOSED?

YES

COMBUSTION AIR PRESSURE

SWITCH CLOSED?

YES

THERMOSTAT DEMAND SATISFIED.

YES

LED #1 & #2 SIMULTANEOUS SLOW FLASHES.

YES

COMB. AIR INDUCER CONTINUES 5-SECOND

POST PURGE AFTER T’STAT DEMAND IS SATISFIED.

INDOOR AIR BLOWER COMPLETES SELECTED OFF"

DELAY BEFORE SHUTTING OFF.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET

THERMOSTAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

GAS VALVE DE−ENERGIZED.

COMBUSTION AIR INDUCER ON.

INDOOR BLOWER OFF WITH DELAY

LED #1 −− OFF. LED #2 −− SLOW FLASH.

HAS CAB SWITCH CLOSED IN 2.5 MINUTES?

5-MINUTE PRESSURE SWITCH

GAS VALVE POWER OFF.

COMBUSTION AIR INDUCER POWER ON.

INDOOR BLOWER ON

LED #1 −− ON. LED #2 −− SLOW FLASH.

AND MAIN POWER IS INTERRUPTED OR

WATCHGUARD MODE.

Page 43

YES

Page 44

COOLING SEQUENCE OF OPERATION

NORMAL COOLING MODE ABNORMAL COOLING MODE

POWER ON

IGNITION CONTROL MAIN POWER ON.

CONTROL SELF DIAGNOSTIC CHECK.

IS CONTROL OPERATING NORMALLY?

YES

IS THERE A PROPER GROUND?

YES

IS POLARITY CORRECT?

YES

IS VOLTAGE

ABOVE 90 VOLTS?

YES

ROLLOUT SWITCH MONITORED CONTINUOUSLY.

IS ROLLOUT SWITCH CLOSED?

YES

GAS VALVE OFF. COMBUSTION AIR INDUCER OFF.

INDOOR BLOWER OFF WITH NORMAL DELAY.

SIGNAL CIRCUIT BOARD FAILURE AT LED.

INTERRUPT MAIN POWER TO RESET CONTROL.

AND MAIN POWER IS INTERRUPTED OR THERMOSTAT

SIGNAL IMPROPER GROUND AT LED.

CONTROL WILL CONTINUE TO CALL FOR COOLING

IN THIS CONDITION.

SIGNAL POLARITY REVERSED AT LED. CONTROL

WILL CONTINUE TO CALL FOR COOLING IN THIS

CONDITION.

LED SIGNALS LOW VOLTAGE. CONTROL WILL

CONTINUE TO CALL FOR COOLING

IN THIS CONDITION.

GAS VALVE OFF. COMBUSTION AIR INDUCER ON.

INDOOR BLOWER ON.

SIGNAL ROLL-OUT SWITCH OPEN AT LED.

SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES

IS CYCLED OFF/ON FOR 1 SEC. MINIMUM.

LED: SLOW FLASH RATE REMAINS UNCHANGED

THROUGHOUT COOLING CYCLE.

THERMOSTAT CALLS FOR COOLING.

COMPRESSOR CONTACTOR AND SYSTEM FAN

ENERGIZED WITH 2-SECOND DELAY

(COOLING SPEED). EAC TERM. ENERGIZED.

THERMOSTAT OPENS.

COMPRESSOR OFF.

SYSTEM FAN AND EAC TERM. OFF

WITH 45-SECOND DELAY.

Page 44

Page 45

CONTINUOUS HEAT SPEED FAN SEQUENCE OF OPERATION

LED: SLOW FLASH RATE REMAINS

UNCHANGED THROUGHOUT SEQUENCE.

MANUAL FAN SELECTION MADE AT THERMOSTAT.

CONTROL (G) ENERGIZES SYSTEM FAN AT HEAT

SPEED. EAC TERMINAL IS ENERGIZED.

THERMOSTAT CALLS FOR HEAT (W).

THERMOSTAT CALLS FOR COOLING.

YES

SYSTEM FAN SWITCHED TO COOL SPEED.

EAC TERM. REMAINS ON.

THERMOSTAT OPENS.

MANUAL FAN SELECTION MADE AT THERMOSTAT.

CONTROL (G) ENERGIZES SYSTEM FAN AT HEAT

SPEED. EAC TERM. ENERGIZED.

HUM TERM. ENERGIZES

WITH COMB. AIR INDUCER.

YES

SYSTEM FAN REMAINS ON

HEATING SPEED.

THERMOSTAT OPENS.

HUM TERM. DE−ENERGIZES

WITH COMB. AIR INDUCER

SYSTEM FAN REMAINS ON

HEATING SPEED.

Page 45

Page 46

VIII−Integrated Control Troubleshooting Chart

UPON INITIAL POWER UP, REMOVE ALL THERMOSTAT DEMANDS TO THE UNIT

PROBLEM: 1 UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE

Condition Possible Cause Corrective Action / Comments

1.1

− Both diagnostic lights fail to light up.

Main voltage 120V not supplied to unit.

1.1.1

ACTION 1 − Check 120V main voltage.

Determine cause of main power failure.

LED#1−Off LED#2−Off

1.2

− Diagnostic lights flash the roll−out .

code.

LED#1−On, LED#2−Slow Flash

1.3

− Both diagnostic lights the polarity

code.

LED#1−Fast Flash, LED#2−Slow Flash.

1.4

1.1.2

Miswiring of furnace or improper connections.

1.1.3

Blown fuse

1.1.4

Door interlock switch failure.

1.1.5

Transformer Failure.

1.1.6

Failed control.

1.2.1

Roll−out switch open.

1.2.2

Roll−out switch failure.

1.2.3

Miswiring or improper connections at roll−out switch.

1.2.4

12 pin connector failure

1.3.1

120V main power polarity reversed.

1.4.1

Open combustion air inducer motor circuit.

ACTION 1 − Check for correct wiring of 120V to power make up box and transformer.

ACTION 2 − Check 24V wiring to control.

ACTION 1 − Replace fuse. ACTION 2 − If fuse still blows, check for short.

ACTION 1 − Check that door switch is activated

when door is closed. ACTION 2 − Check wire connections to switch, replace loose connectors. ACTION 3 − Check continuity of switch in closed position. Replace if defective.

ACTION 1 − Check that transformer output is 24V. Replace if defective.

ACTION 1 − If all the above items have been checked, replace control.

ACTION 1 − Manually reset the roll−out switch by pushing the top button. ACTION 2 − Determine the cause of the roll−out switch activation before leaving furnace.

ACTION 1 − Check continuity across roll−out switch. Replace roll−out switch if switch is reset but does not have continuity.

ACTION 1 − Check wiring connections to switch.

ACTION 1 − Check 12−pin connector for proper

connection to control. ACTION 2 − Check continuity of the multi plug pin.

ACTION 1 − Check the 120V has line and neutral correctly input into control. ACTION 2 − Reverse the line and neutral at the 120V field connection.

ACTION 1 − Check for 120V to combustion air inducer. If no power, check wire and connections.

LED#1−Slow Flash LED#2−Slow Flash

1.4.2

Failed combustion air inducer motor.

Page 46

ACTION 1 − If power is present at blower, replace blower.

Page 47

PROBLEM 1: UNIT FAILS TO OPERATE IN THE COOLING, HEATING, OR CONTINUOUS FAN MODE

Condition Possible Cause Corrective Action / Comments

1.5

− Diagnostic lights flash the improper

main ground.

LED#1−Alternating Fast Flash* LED#2−Alternating Fast Flash*

1.5.1

Improper ground to the unit.

1.5.2

4−Pin connector is improperly at-

tached to the circuit board.

1.5.3

Line voltage is below 90V

ACTION 1 − Check that the unit is properly ground. ACTION 2 − Install a proper main ground to the unit

ACTION 1 − Check 4−pin connector for proper installation. Correctly insert connector into control.

ACTION 1 − Check that the line voltage is correct. Determine cause of voltage drop and supply correct voltage to the control.

PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER DOES NOT

ENERGIZE

Condition Possible Cause Corrective Action / Comments

2.1

− Unit operates with a cooling or contin-

uous fan demand.

− Combustion air inducer will not start with a Heating demand.

− Diagnostic lights flash the limit failure mode.

LED#1−Slow Flash, LED#2−On

2.1.1

Primary or secondary (if equipped )

limit open.

2.1.2

Miswiring of furnace or improper con-

nections at limit switch(es).

ACTION 1 − Check continuity across switch(es). Switches reset automatically upon cool down. ACTION 2 − Check for restrictions on blower inlet air (including filter) and outlet air. Determine cause for limit activation before placing unit back in operation.

ACTION 1 − Check for correct wiring and loose connections. Correct wiring and/or replace any loose connections.

2.2

− Unit operates with a cooling and continuous fan demand.

− Combustion air inducer will not start with a Heating demand.

− Diagnostic lights flash the pressure switch failure code.

LED#1−Off, LED#2−Slow Flash

2.2.1

Miswiring of furnace or improper con-

nections to combustion air inducer.

2.2.2

Pressure switch stuck closed.

ACTION 1 − Check for correct wiring and loose connections. Correct wiring and/or replace any loose connections.

ACTION 1 − Check that the pressure switch is open without the combustion air inducer operating. Replace if defective.

Page 47

Page 48

PROBLEM 2: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER DOES

NOT ENERGIZE (CONT.).

Condition Possible Cause Corrective Action/Comments

2.3

− Unit operates with a cooling and continuous fan demand.

− Combustion air inducer will not start with a Heating demand.

Miswiring of furnace or improper con-

nections to combustion air inducer.

2.3.1

ACTION 1 − Check for correct wiring and loose

connections. Correct wiring and/or replace any loose connections.

− Diagnostic lights flash the pressure switch failure code 2.5 minutes after heating demand.

ACTION 1 − If there is 120V to combustion air inducer and it does not operate, replace combustion air inducer.

LED#1−Off,

2.3.2

Combustion air inducer failure.

LED#2−Slow Flash

PROBLEM 3: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR INDUCER

ENERGIZES, IGNITOR IS NOT ENERGIZED.

Condition Possible Cause Corrective Action/Comments

3.1

− Unit operates with a cooling and

continuous fan demand.

− Combustion air inducer energizes with a heating demand.

− Diagnostic lights flash the pressure switch failure code 2.5 minutes after heating demand.

LED#1−Off LED#2−Slow Flash

Pressure switch does not close due

to incorrect routing of the pressure

Pressure switch does not close due

to obstructions in the pressure lines.

Pressure switch lines damaged

Condensate in pressure switch line.

Pressure switch does not close due to a low differential pressure across

the pressure switch.

Wrong pressure switch installed in the

unit, or pressure switch is out of cal-

Miswiring of furnace or improper con-

nections at pressure switch.

Pressure switch failure.

3.1.1

switch lines.

3.1.2

3.1.3

3.1.4

3.1.5

3.1.6

ibration.

3.1.7

3.1.8

ACTION 1 − Check that the pressure switch lines

are correctly routed. Correctly route pressure switch lines.

ACTION 1 − Remove any obstructions from the the pressure lines and/or taps.

ACTION 1 − Check pressure switch lines for leaks. Replace any broken lines.

ACTION 1 − Check pressure switch lines for condensate. Remove condensate from lines.

ACTION 1 − Check the differential pressure across the pressure switch. This pressure should exceed the set point listed on the switch. ACTION 2 − Check for restricted inlet vent. Remove all blockage. ACTION 3 − Check for proper vent sizing and run length.

ACTION 1 − Check that the proper pressure switch is installed in the unit. Replace pressure switch if necessary.

ACTION 1 − Check for correct wiring and loose connections. Correct wiring and/or replace any loose connections.

ACTION 1 − If all the above modes of failure have been checked, the pressure switch may have failed. Replace pressure switch and determine if unit will operate.

Page 48

Page 49

PROBLEM 4: UNIT FAILS TO FIRE IN THE HEATING MODE, COMBUSTION AIR BLOWER

ENERGIZES, IGNITOR IS ENERGIZED.

Condition Possible Cause Corrective Action/Comments

4.1

− Unit operates with a cooling and continuous fan demand.

− Combustion air inducer energizes with Heating demand.

− Ignitor is energized but unit fails to light.

LED#1−Alternating Slow Flash LED#2−Alternating Slow Flash

4.1.1

Check that gas is being supplied to

the unit.

4.1.2

Miswiring of gas valve or loose con-

nections at multi−pin control amp

plugs or valve.

4.1.3

Defective gas valve or ignition con-

trol.

ACTION 1 − Check line pressure at the gas valve. Pressure should not exceed 13" WC for both natural and propane. Line pressure should read a minimum 4.5" WC for natural and 11.0"WC for propane.

ACTION 1 − Check for correct wiring and loose connections. Correct wiring and/or replace any loose connections.

ACTION 1 − Check that 24V is supplied to the gas valve approximately 35 seconds after heat demand is initiated. ACTION 2 − Replace the valve if 24V is supplied but valve does not open. ACTION 3 − Replace the control if 24V is not supplied to valve.

PROBLEM 5: BURNERS LIGHT WITH A HEATING DEMAND BUT UNIT SHUTS DOWN

PREMATURELY

Condition Possible Cause Corrective Action/Comments

5.1

− Burners fire with a heating demand.

− Burners light but unit shuts off prior to satisfying T−stat demand.

− Diagnostic lights flash the pressure switch code.

LED#1−Off LED#2−Slow Flash

5.2

− Combustion air inducer energizes with a heating demand.

− Burners light but fail to stay lit.

− After 5 tries the control diagnostics flash the watchguard burners failed to ignite code.

LED#1−Alternating Slow Flash LED#2−Alternating Slow Flash

5.1.1

Low pressure differential at the pres-

sure switch.

5.1.2

Wrong concentric vent kit used for

terminating the unit.

5.1.3

Condensate drain line is not draining

properly.

5.2.1

Sensor or sense wire is improperly

installed.

5.2.2

Sensor or sense wire is broken.

5.2.3

Sensor or sensor wire is grounded to

the unit.

5.2.4

Control does not sense flame.

ACTION 1 − Check for restricted intake/exhaust vent. Remove all blockage. ACTION 2: Check for proper vent sizing. See installation instructions.

ACTION 1 − Check vent termination kit installed. See Placement and Installation section.

ACTION 1 − Check condensate line for proper vent slope, and any blockage. Condensate should flow freely during operation of furnace. Repair or replace any improperly installed condensate lines.

ACTION 1 − Check that sensor is properly located and that the sense wire is properly attached to both the sensor and the control.

ACTION 1 − Check for a broken sensor. ACTION 2 − Test continuity across the sense

wire. If wire or sensor are damaged replace the component.

ACTION 1 − Check for resistance between the sensor rod and the unit ground. ACTION 2 − Check for resistance between the sensor wire and the unit ground.

ACTION 3 − Correct any shorts found in circuit.

ACTION 1 − Check the microamp signal from

the burner flame. If the microamp signal is below normal, check the sense rod for proper location or contamination. ACTION 2 − Replace, clean, or relocate flame sense rod. If rod is to be cleaned, use steel wool or replace sensor. DO NOT CLEAN ROD WITH SAND PAPER. SAND PAPER WILL CONTRIBUTE TO THE CONTAMINATION PROBLEM. NOTE: Do not attempt to bend sense rod.

Page 49

Page 50

PROBLEM 5: BURNERS LIGHT WITH HEATING DEMAND BUT UNIT SHUTS DOWN

Condition Possible Cause Corrective Action/Comments

5.3

− Combustion air inducer energizes with a heating demand.

− Burners light.

− Roll−out switch trips during the heating demand.

− Diagnostic lights flash roll−out failure.

LED#1−On LED#2−Slow Flash

PREMATURELY (CONT.)

5.3.1

Unit is firing above 100% of the

nameplate input.

5.3.2

Gas orifices leak at the manifold con-

nection.

5.3.3

Air leakage at the connections be-

tween the primary heat exchanger,

secondary heat exchanger, and com-

bustion air blower.

ACTION 1 − Check that the manifold pressure matches value listed on nameplate. See installation instructions for proper procedure. ACTION 2 − Verify that the installed orifice size match the size listed on the nameplate or installation instructions. ACTION 3 − Check gas valve sensing hose to insure no leaks are present. ACTION 4 − Check the input rate to verify rate matches value listed on nameplate.

ACTION 1 − Tighten orifice until leak is sealed. NOTE: Be careful not to strip orifice threads. ACTION 2 − Check for gas leakage at the

threaded orifice connection. Use approved method for leak detection (see unit instructions).

ACTION 1 − Check for air leakage at all joints in the heat exchanger assembly. Condition will cause high CO2 with high CO. ACTION 2 − Seal leakage if possible, replace heat exchanger if necessary, tag and return heat exchanger to proper Lennox personnel.

5.4

− Combustion air inducer energizes

with a heating demand.

− Burners light roughly and the unit fails to stay lit.

− Diagnostic lights flash watchguard flame failure.

LED#1−Alternating Slow Flash LED#2−Alternating Slow Flash

5.3.4

Insufficient flow through the heat ex-

changer caused by a sooted or re-

stricted heat exchanger.

5.3.5

Burners are not properly located in

the burner box.

5.4.1

Recirculation of flue gases. This con-

dition causes rough ignitions and op-

eration. Problem is characterized by

nuisance flame failures.

5.4.2

Improper burner cross−overs

5.4.3

Pressure Switch opens 5 times during

a single demand

ACTION 1 − Check for sooting deposits or other restrictions in the heat exchanger assembly. Clean assembly as outlined in instruction manual.

ACTION 2 − Check for proper combustion.

ACTION 1 − Check that the burners are firing into

the center of the heat exchanger openings. Correct the location of the burners if necessary.

ACTION 1 − Check for proper flow of exhaust gases away from intake vent. Remove any obstacles in front of the intake and exhaust vent which would cause recirculation. ACTION 2 − Check for correct intake and exhaust vent installation. See instructions

ACTION 1 − Remove burner and inspect the cross−overs for burrs, or any restriction or if crossover is warped. Remove restriction or replace burners.

ACTION 1 − Inspect vent pipe installation and for any restriction. Remove restriction. ACTION 2 − Check pressure switch reliability.

Page 50

Page 51

PROBLEM 6: CONTROL SIGNALS LOW FLAME SENSE DURING HEATING MODE

Condition Possible Cause Corrective Action/Comments

6.0

− Unit operates correctly but the diagnostic lights flash low flame sense

Sensor rod is improperly located on

6.1.1

the burner.

ACTION 1 − Check the sensor rod for proper location on the burner. Properly locate the sensor rod or replace if rod cannot be located correctly.

code.

ACTION 1 − Check sensor rod for contamination or coated surface. Clean the sensor rod with steel wool or replace sensor. DO NOT USE SAND PAPER TO CLEAN ROD. SAND PAPER WILL CONTRIBUTE TO THE CONTAMINATION PROBLEM.

LED#1−Slow Flash LED#2−Fast Flash

6.1.2

Sensor rod is contaminated.

PROBLEM 7: INDOOR BLOWER FAILS TO OPERATE IN COOLING, HEATING, OR CONTINUOUS

FAN MODE

Condition Possible Cause Corrective Action/Comments

7.0

− Indoor blower fails to operate in continuous fan, cooling, or heating mode.

Miswiring of furnace or improper con-

nections at control or indoor blower

120V is not being supplied to the indoor air blower or blower motor fail-

7.1.1

motor.

7.1.2

ure.

ACTION 1− Correct wiring and/or replace any loose connections. Check for correct wiring and loose connections.

ACTION 1 − Check for 120V at the various calls for indoor blower by energizing "Y", "G", and "W" individually on the low voltage terminal strip. Note that when "W’ is energized, the blower is delayed 45 seconds. If there is 120V to each motor tap but the blower does not operate, replace the motor.

Condition Possible Cause Corrective Action/Comments

8.0

− AM radio interference.

7.1.3

Defective control

7.1.4

Defective run capacitor

ACTION 1 − If there is not 120V when "Y", "G", or "W" is energized, replace the control.

ACTION 1 − Replace capacitor

PROBLEM 8: RF STATIC DURING TIME FOR IGNITION

8.1.2

Ignitor operation

ACTION 1 − Call Technical Support, Dallas.

Page 51

Lennox ML193UH045P36B, ML193UH090P36C, ML193UH070P36B, ML193UH110P48C, ML193UH110P60C Unit Information

Specifications and Main Features

Frequently Asked Questions

User Manual