Lennox ML193UH045P36B, ML193UH090P36C, ML193UH070P36B, ML193UH110P48C, ML193UH110P60C Unit Information
...
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.
Page 1
© 2010 Lennox Industries Inc.
Litho U.S.A.
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.
1
Annual Fuel Utilization Efciency 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
1
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.
1
Annual Fuel Utilization Efciency 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
1
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
Page 2
OPTIONAL ACCESSORIES - MUST BE ORDERED EXTRA
“B” Width
Models
CABINET ACCESSORIES
Horizontal Suspension Kit - Horizontal only 51W10 51W10 51W10
Return Air Base - Upow 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
1
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 specic 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)
1
Cleanable polyurethane frame type lter.
2
Kits contain enough parts for two, non−direct vent installations.
3
Non−direct vent only.
NOTE - Termination Kits 44W92, 44W93, 30G28, 81J20 are certied 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
3
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.
1
Allow proper clearances to accommodate condensate trap and vent pipe installation.
2
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
1
0 inches (0 mm)
Rear 0 inches (0 mm)
Front 0 inches (0 mm)
2
Floor
Combustible
Page 3
LPG/Propane
to Natural Gas Kit
Natural Gas
High Altitude
Orice Kit
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
Low
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
Low
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
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
Page 4
Medium-
Low
Low
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.
Page 5
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
TM
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
Page 6
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
2
3
4
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
Page 7
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
Page 8
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.
ON
ON
OFF
ON
OFF
ON
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.
*4
Sec.Trial
for Ign.
**Blower On"
Delay
End of
Heat Demand
5 SEC
Post
Purge
Blower
Off
Time
ON
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
Page 9
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
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
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
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
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
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
2
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.
2
2
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)
2
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)
2
per 1.17kW) per hour
of the total input rating of all equipment in the enclosure.
FIGURE 15
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
2
per .59kW) per hour of the total
2
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
Loading...