Page 2 SPECIFICATIONS Gas Heating Performance Model No. ML180UH045E36A ML180UH070E36A ML180UH070E36B ML180UH090E48B Model No. - Low Nox ML180UH045XE36AML180UH070XE36A ML180UH070XE36B ML180UH090XE48B
UNIT INFORMATION Corp 1120-L4 ML180UHE(X) Service Literature Revised 10-2017 ML180UHE(X) SERIES UNITS ML180UHE(X) series units are mid-efficiency gas furnaces used for upflow or horizontal applications only, manufactured with Lennox Duralok heat exchangers formed of aluminized steel. ML180UHE(X) units are available in heating capacities of 44,000 to 132,000 Btuh and cooling applications 2 to 5 tons. Refer to Engineering Handbook for proper sizing. Units are factory equipped for use with natural gas. Kits are available for conversion to LP/Propane operation. ML180UHE(X) model units are equipped with a hot surface ignition system. The ML180UHE(X) unit meets the California Nitrogen Oxides (NOx) Standards and California Seasonal Efficiency requirements. All units use a redundant gas valve to assure safety shutoff as required by C.S.A. All specifications in this manual 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. In the absence of local or state codes, the guidelines and procedures outlined in this manual (except where noted) are recommended only and do not constitute code. WARNING Improper installation, adjustment, alteration, service or maintenance can cause property damage, personal injury or loss of life. Installation and service must be performed by a licensed professional HVAC installer (or equivalent), service agency or the gas supplier. TABLE OF CONTENTS Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 2 Blower Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 4 Parts Identification . . . . . . . . . . . . . . . . . . . . . . . . . Page 6 I Unit Components . . . . . . . . . . . . . . . . . . . . . . . . Page 7 II Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21 III Start Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 21 IV Heating System Service Checks . . . . . . . . . Page 21 V Typical Operating Characteristics . . . . . . . . . Page 26 VI Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . Page 26 VII Wiring and Sequence of Operation . . . . . . Page 29 WARNING Electric Shock Hazard. Can cause injury or death. Unit must be properly grounded in accordance with national and local codes. Line voltage is present at all components when unit is not in operation on units with single-pole contactors. Disconnect all remote electric power supplies before opening access panel. Unit may have multiple power supplies. CAUTION As with any mechanical equipment, contact with sharp sheet metal edges can result in personal injury. Take care while handling this equipment and wear gloves and protective clothing. Page 1 ©2016 Lennox Industries, Inc. S P E C I F I C AT I O N S Gas Heating Performance Model No. ML180UH045E36A ML180UH070E36A ML180UH070E36B ML180UH090E48B Model No. - Low Nox ML180UH045XE36A ML180UH070XE36A ML180UH070XE36B ML180UH090XE48B 1 AFUE 80% 80% 80% 80% Input - Btuh 44,000 66,000 66,000 88,000 Output - Btuh 36,000 53,000 53,000 72,000 Temperature rise range - °F 15 - 45 40 - 70 40 - 70 35 - 65 Gas Manifold Pressure (in. w.g.) Nat. Gas / LPG/Propane 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 High Static - in. w.g. 0.50 0.50 0.50 0.50 Connections Flue connection - in. round 4 4 4 4 in. Gas pipe size IPS 1/2 1/2 1/2 1/2 Indoor Blower Wheel nom. dia. x width - in. Motor Type 10 x 8 DC Brushless 10 x 10 DC Brushless 10 x 10 DC Brushless 10 x 10 DC Brushless Motor output - hp 1/2 1/2 1/2 3/4 Tons of add-on cooling 1.5 - 3 1.5 - 3 1.5 - 3 2.5 - 4 Air Volume Range - cfm 350 - 1380 625 - 1435 395 - 1415 750 - 1785 Electrical Voltage 120 volts - 60 hertz - 1 phase Data Blower motor full load amps 6.8 6.8 6.8 8.4 Maximum overcurrent protection 15 15 15 15 Shipping Data lbs. - 1 package 111 111 127 142 S P E C I F I C AT I O N S Gas Heating Performance Model No. Model No. - Low Nox 1 AFUE ML180UH090E60C - - 80% ML180UH110E60C ML180UH110XE60C 80% ML180UH135E60D - - 80% Input - Btuh 88,000 110,000 132,000 Output - Btuh 72,000 90,000 107,000 Temperature rise range - °F 30 - 60 35 - 65 30 - 60 Gas Manifold Pressure (in. w.g.) Nat. Gas / LPG/Propane 3.5 / 10.0 3.5 / 10.0 3.5 / 10.0 High Static - in. w.g. 0.50 0.50 0.50 Connections Flue connection - in. round 4 4 4 in. Gas pipe size IPS 1/2 1/2 1/2 Indoor Blower Wheel nom. dia. x width - in. Motor Type 11-1/2 x 10 DC Brushless 11-1/2 x 10 DC Brushless 11 x 11 DC Brushless Motor output - hp 1 1 1 Tons of add-on cooling 3 - 5 3 - 5 3.5 - 5 Air Volume Range - cfm 990 - 2290 920 - 2315 1140 - 2495 Electrical Data Voltage Blower motor full load amps 120 volts - 60 hertz - 1 phase 10.9 10.9 10.9 Maximum overcurrent protection 15 15 15 Shipping Data lbs. - 1 package 152 160 178 NOTE - Filters and provisions for mounting are not furnished and must be field provided. 1 Annual Fuel Utilization Efficiency based on DOE test procedures and according to FTC labeling regulations. Isolated combustion system rating for non-weatherized furnaces. Page 2 OPTIONAL ACCESSORIES - ORDER SEPARATELY "A" Width Models CABINET ACCESSORIES Horizontal Suspension Kit - Horizontal only Return Air Base - Upflow only High Performance Economizer (Commercial Only) CONTROLS iComfort® M30 Smart Wi-Fi Thermostat Remote Outdoor Air Temperature Sensor Blower Relay Kit (for two-stage outdoor units) Furnace Twinning Kit FILTERS 1 Air Filter and Rack Kit Horizontal (end) Size of filter - in. Side Return Single Ten Pack Size of filter - in. NIGHT SERVICE KIT Night Service Kit VENTING Vent Adaptor - 6 in. conn. size upflow applications only 1 Cleanable polyurethane, frame-type filter. 51W10 65W75 10U53 15Z69 X2658 85W66 16W72 87L95 14 x 25 x 1 44J22 66K63 16 x 25 x 1 84W47 18M79 "B" Width Models 51W10 50W98 10U53 15Z69 X2658 85W66 16W72 87L96 18 x 25 x 1 44J22 66K63 16 x 25 x 1 84W47 18M79 "C" Width Models 51W10 50W99 10U53 15Z69 X2658 85W66 16W72 87L97 20 x 25 x 1 44J22 66K63 16 x 25 x 1 84W47 18M79 "D" Width Models 51W10 51W00 10U53 15Z69 X2658 85W66 16W72 87L98 25 x 25 x 1 44J22 66K63 16 x 25 x 1 84W47 18M79 GAS HEAT ACCESSORIES Input High Altitude Pressure Switch Kit 0 - 4500 ft. 4501 - 7500 ft. 7501 - 10,000 ft. 045 No Change 80W52 80W51 070 No Change 80W52 80W51 090 No Change 80W52 80W51 110 No Change 80W52 80W52 135 No Change 80W52 80W51 Natural Gas to LPG/Propane Kit LPG/Propane to Natural Gas Kit Natural Gas High Altitude Orifice Kit 0 - 7500 ft. 7501 - 10,000 ft. 0 - 7500 ft. 7501 - 10,000 ft. 11K49 11K44 73W81 73W37 11K49 11K44 73W81 73W37 11K49 11K44 73W81 73W37 11K49 11K44 73W81 73W37 11K49 11K44 73W81 73W37 HIGH ALTITUDE NOTE - Units may be installed at altitudes up to 2000 ft. above sea level without any modifications. At altitudes above 2000 ft. units must be derated to match information in the shaded areas shown below. NOTE - This is the only permissible derate for these units. Gas Manifold Pressure (Outlet) in. w.g. Line Pressure - in. w.g. Input 0 - 2000 Feet 2001 - 4500 Feet Natural LPG/ Natural LPG/ Gas Propane Gas Propane 045 3.5 10 3.2 10 070 3.5 10 3.2 10 090 3.5 10 3.2 10 110 3.5 10 3.5 10 135 3.5 10 3.5 10 1 Natural Gas High Altitude Orifice Kit required. 4501 - 7500 Feet Natural LPG/ Gas Propane 7501 - 10,000 ft. 1 Natural LPG/ Gas Propane Minimum Natural LPG/ Gas Propane Maximum 3 10 3.5 10 4.5 11 13 2.8 10 3.5 10 4.5 11 13 2.7 9.6 3.5 10 4.5 11 13 3 9.6 3.5 10 4.5 11 13 2.9 9.6 3.5 10 4.5 11 13 Page 3 BLOWER DATA ML180UH045E36A PERFORMANCE (Less Filter) External Static Pressure in. w.g. High (Black) cfm Watts Air Volume / Watts at Various Blower Speeds Medium-High (Brown) Medium (Blue) Medium-Low (Yellow) cfm Watts cfm Watts cfm Watts 0.00 1380 265 1155 165 995 120 975 115 0.10 1345 270 1120 175 950 120 880 105 0.20 1320 285 1080 190 900 125 805 105 0.30 1290 295 1055 200 875 135 750 110 0.40 1265 310 1010 205 825 145 710 120 0.50 1230 315 990 215 790 155 660 125 0.60 1190 330 945 230 750 165 630 135 0.70 1165 340 915 235 705 170 570 140 0.80 1130 350 880 245 670 180 535 150 ML180UH070E36A PERFORMANCE (Less Filter) External Static Pressure in. w.g. High (Black) cfm Watts Air Volume / Watts at Various Blower Speeds Medium-High (Brown) Medium (Blue) Medium-Low (Yellow) cfm Watts cfm Watts cfm Watts 0.00 - - - - - - - - - - - - - - - - - - - - - - - - 0.10 1435 282 1215 178 1120 147 1095 133 0.20 1400 290 1170 187 1090 154 1050 141 0.30 1365 303 1145 198 1055 164 1025 153 0.40 1335 311 1105 206 1015 172 985 160 0.50 1310 325 1075 216 980 177 945 169 0.60 1285 341 1040 224 950 187 905 175 0.70 1250 344 1010 235 905 196 865 183 0.80 1215 354 975 244 860 204 830 191 ML180UH070E36B PERFORMANCE (Less Filter) External Static Pressure in. w.g. High (Black) cfm Watts Air Volume / Watts at Various Blower Speeds Medium-High (Brown) Medium (Blue) Medium-Low (Yellow) cfm Watts cfm Watts cfm Watts 0.00 - - - - - - - - - - - - - - - - - - - - - - - - 0.10 1415 280 1295 170 1145 145 1130 130 0.20 1355 290 1225 185 1110 150 1080 140 0.30 1330 300 1190 200 1060 160 1035 155 0.40 1290 310 1155 205 1015 175 970 160 0.50 1245 325 1115 215 980 180 930 170 0.60 1225 335 1045 230 920 190 865 180 0.70 1190 350 1000 235 855 205 790 190 0.80 1160 365 925 245 790 205 735 200 ML180UH090E48B PERFORMANCE (Less Filter) External Static Pressure in. w.g. High (Black) cfm Watts Air Volume / Watts at Various Blower Speeds Medium-High (Brown) Medium (Blue) Medium-Low (Yellow) cfm Watts cfm Watts cfm Watts 0.00 1785 380 1570 270 1440 220 1395 190 0.10 1755 395 1535 275 1420 230 1350 205 0.20 1730 415 1505 290 1380 245 1310 215 0.30 1690 435 1460 305 1345 260 1275 230 0.40 1645 440 1435 320 1310 270 1240 240 0.50 1615 455 1395 335 1265 285 1180 255 0.60 1590 470 1350 350 1210 290 1150 265 0.70 1545 475 1300 360 1175 305 1095 275 0.80 N/A N/A 1270 370 1140 310 1040 285 Page 4 Low (Red) cfm Watts 945 105 865 100 700 85 640 90 595 95 535 100 500 110 435 115 380 120 Low (Red) cfm Watts - - - - - - 930 88 875 98 845 102 795 110 760 117 705 125 665 129 625 136 Low (Red) cfm Watts - - - - - - 955 95 885 100 825 110 770 120 695 125 625 135 540 140 445 145 Low (Red) cfm Watts 1190 120 1140 130 1110 145 1065 155 1010 165 955 180 915 185 860 200 820 210 ML180UH090E60C PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air from Both Sides or Return External Air from Bottom and One Side. Static Pressure in. w.g. High (Black) MediumHigh (Brown) Medium (Blue) MediumLow (Yellow) Low (Red) Single Side Return Air - Air volumes in bold (over 1800 cfm) require Optional Return Air Base and field fabricated transition to accommodate 20 x 25 x 1 in. air filter in order to maintain proper air velocity. High (Black) MediumHigh (Brown) Medium (Blue) MediumLow (Yellow) Low (Red) cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts 0.00 2255 640 1940 420 1750 310 1580 230 1485 185 2290 655 1980 425 1775 310 1605 235 1495 195 0.10 2200 655 1910 440 1705 315 1535 240 1385 190 2250 675 1945 445 1730 320 1555 245 1400 190 0.20 2150 675 1865 450 1655 340 1490 260 1340 205 2210 695 1885 465 1680 340 1510 265 1350 205 0.30 2125 695 1835 475 1635 355 1450 275 1285 215 2165 715 1850 475 1645 355 1470 275 1285 215 0.40 2090 715 1800 495 1585 370 1405 285 1235 230 2135 720 1810 490 1595 370 1410 290 1225 230 0.50 2060 735 1760 510 1545 385 1370 305 1200 245 2070 735 1765 515 1545 390 1370 305 1180 245 0.60 2020 750 1725 525 1515 405 1320 320 1145 255 2030 760 1715 530 1495 405 1325 320 1140 255 0.70 1980 765 1680 540 1465 420 1265 330 1105 270 1990 775 1685 540 1450 425 1265 330 1095 270 0.80 1935 785 1635 560 1420 435 1225 350 1055 285 1950 795 1645 560 1415 435 1225 345 1040 285 ML180UH110E60C PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air with Return Air from Both External Sides or Return Air from Bottom and One Side. Static Pressure in. w.g. High (Black) MediumHigh (Brown) Medium (Blue) MediumLow (Yellow) Low (Red) Single Side Return Air - Air volumes in bold (over 1800 cfm) require Optional Return Air Base and field fabricated transition to accommodate 20 x 25 x 1 in. air filter in order to maintain proper air velocity. High (Black) MediumHigh (Brown) Medium (Blue) MediumLow (Yellow) Low (Red) cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts 0.00 2230 635 1945 430 1715 295 1555 230 1470 185 2315 645 1990 415 1780 300 1610 230 1510 200 0.10 2180 655 1905 445 1690 305 1510 240 1340 175 2260 655 1945 425 1740 315 1550 240 1400 185 0.20 2135 680 1865 465 1630 330 1470 260 1280 190 2210 680 1895 450 1680 335 1510 255 1350 200 0.30 2090 695 1830 480 1595 345 1440 275 1235 200 2165 700 1850 465 1650 355 1455 275 1285 210 0.40 2050 715 1785 495 1550 360 1385 285 1175 210 2130 715 1830 485 1585 365 1395 285 1230 225 0.50 2025 730 1740 520 1500 375 1340 300 1130 225 2095 730 1770 500 1535 385 1365 300 1175 235 0.60 2010 750 1710 535 1470 390 1305 320 1080 240 2055 755 1725 515 1495 400 1305 315 1135 250 0.70 1965 755 1670 555 1420 410 1255 330 1015 255 2000 765 1675 535 1465 410 1255 325 1080 265 0.80 1905 785 1635 560 1380 425 1215 350 975 270 1965 785 1640 555 1400 425 1210 345 1025 275 ML180UH135E60D PERFORMANCE (Less Filter) Air Volume / Watts at Different Blower Speeds Bottom Return Air, Side Return Air with Return Air from Both External Sides or Return Air from Bottom and One Side. Static Pressure in. w.g. High (Black) MediumHigh (Brown) Medium (Blue) MediumLow (Yellow) Low (Red) Single Side Return Air - Air volumes in bold (over 1800 cfm) require Optional Return Air Base and field fabricated transition to accommodate 20 x 25 x 1 in. air filter in order to maintain proper air velocity. High (Black) MediumHigh (Brown) Medium Medium-Low Low (Blue) (Yellow) (Red) cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts cfm Watts 0.00 2495 755 2295 590 2045 435 1845 315 1650 230 2365 725 2295 575 2005 410 1820 300 1635 235 0.10 2440 780 2220 620 2015 445 1820 330 1615 245 2350 745 2210 595 2000 435 1745 320 1530 230 0.20 2390 790 2175 640 1935 470 1735 350 1550 255 2330 775 2175 625 1945 455 1730 330 1490 250 0.30 2360 805 2140 655 1895 490 1720 370 1485 275 2245 785 2135 645 1895 475 1655 355 1425 265 0.40 2285 835 2125 675 1850 510 1660 380 1455 290 2215 810 2085 660 1840 495 1600 375 1385 285 0.50 2240 860 2060 690 1815 535 1610 400 1415 310 2175 825 2045 680 1815 505 1590 390 1340 290 0.60 2225 865 2015 715 1785 550 1535 420 1330 320 2125 845 1995 700 1765 530 1525 405 1300 310 0.70 2160 895 1955 735 1755 570 1500 440 1265 340 2095 865 1950 710 1700 545 1485 420 1260 325 0.80 2105 905 1925 750 1715 580 1435 450 P1a21g5e 5345 2065 880 1890 725 1680 565 1415 445 1205 345 PARTS ARRANGEMENT Make-Up Box Heat Exchanger Combustion Air Inducer Combustion Air Inducer Pressure Switch Burner Box (includes sensor, ignitor and rollout switches) Gas Valve Primary Limit (under combustion air inducer) Control Box (includes integrated control, interlock switch and transformer) Upper Access Panel Blower Access Panel Power Choke (4 and 5 Ton Only) FIGURE 1 Blower Assembly Page 6 I-UNIT COMPONENTS ML180UHE(X) unit components are shown in figure 1.The gas valve, combustion air inducer and burners can be accessed by removing the upper access panel. Electrical components are in the control box (figure 2) found in the blower section. ELECTROSTATIC DISCHARGE (ESD) Precautions and Procedures CAUTION Electrostatic discharge can affect electronic components. Take precautions to neutralize electrostatic charge by touching your hand and tools to metal prior to handling the control. 1. Control Transformer (T1) A transformer located in the control box provides power to the low voltage section of the unit. Transformers on all models are rated 40VA with a 120V primary and a 24V secondary. 2. Door Interlock Switch (S51) A door interlock switch rated 14A at 125VAC is wired in series with line voltage. When the blower door is removed the unit will shut down. NOTE - The door interlock switch is a safety switch. Do not by-pass or jumper switch. CONTROL BOX TRANSFORMER (T1) CIRCUIT BREAKER (CB8) DOOR INTERLOCK SWITCH (S51) INTEGRATED IGNITION CONTROL (A92) FIGURE 2 3. Circuit Breaker (CB8) A 24V circuit breaker is also located in the control box. The switch provides overcurrent protection to the transformer (T1). The breaker is rated at 3A at 32V. If the current exceeds this limit the breaker will trip and all unit operation will shutdown. The breaker can be manually reset by pressing the button on the face. 4. Integrated Control (A92) WARNING Shock hazard. Disconnect power before servicing. Control is not field repairable. If control is inoperable, simply replace entire control. Can cause injury or death. Unsafe operation will result if repair is attempted. The hot surface ignition control system consisting of an integrated control (figure 3 with control terminal designations in tables 1, 2 and 3), sensor and ignitor (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 integrated control also features a RED LED for troubleshooting and two accessory terminals rated at (1) one amp. See table 4 or 5. for troubleshooting diagnostic codes. The nitride ignitor is made from a non-porous, high strength proprietary ceramic material that provides long life and trouble free maintenance. Electronic Ignition (Figure 4) On a call for heat the integrated control monitors the combustion air inducer pressure switch. The control will not begin the heating cycle if the pressure switch is closed (bypassed). Once the pressure switch is determined to be open, the combustion air inducer is energized. When the differential in the pressure switch is great enough, the pressure switch closes and a 15-second pre-purge begins. If the pressure switch is not proven within 2-1/2 minutes, the integrated control goes into Watchguard-Pressure Switch mode for a 5-minute re-set period. After the 15-second pre-purge period, the ignitor warms up for 20 seconds during which the gas valve opens at 19 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. Page 7 TABLE 1 4-Pin Terminal Designation PIN # FUNCTION 1 Combustion Air Inducer Line 2 Ignitor Line 3 Combustion Air Inducer Neutral 4 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 TABLE 3 1/4" Quick Connect Terminals 120HUM Humidifier 120VAC LINE 120VAC XFMR Transformer 120VAC CIRC Indoor blower 120VAC EAC Indoor air quality accessory 120VAC NEUTRALS Common 120VAC HUM24 Humidifier 24VAC 3/16" Quick Connect Terminals COOL Cooling tap 24VAC HEAT Heating tap 24VAC FAN Continuous blower 24 VAC PARK (no power) Park terminal for speed taps FS Flame sense 24 COM Common 24VAC INTEGRATED CONTROL (Automatic Hot Surface Ignition System) RED LED RECALL BUTTON BLOWER OFF DELAY FIGURE 3 Page 8 RED LED Flash Code2 Off Heartbeat1 1 2 3 4 5 6 7 8 9 10 11 12 13 Note 1 Note 2 Note3 TABLE 4 (-02 inegrated Control) Diagnostic Codes / Status of Furnace No power to control or board fault detected Normal Operation - Idle, Continuous Fan, Cool Reverse Line Voltage Polarity Improper Earth Ground Burner failed to light, or lost flame during heat demand Low Flame Signal - check flame sensor Watchguard - burner failed to light, exceeded maximum number of retries or recycles. Ignitor Circuit Failure - not available on this control Primary or Secondary Limit Open or Watchguard Mode - Limit Switch Open longer than 3 minutes Rollout Switch Open Pressure Switch failed to close or opened during heat demand Watchguard - Pressure Switch opened 5 times during one heat demand Pressure Switch stuck closed prior to activation of combustion air inducer Flame Sensed without gas valve energized Low Line Voltage Notes A "Heartbeat" is indicated by a "Slow Flash" - 1 sec on 1 sec off, repeating Error codes are indicated by a "rapid flash" - the LED flashes X times at ½ second on ½ second off, remains off for 3 seconds then repeats. Last 10 error codes are stored in memory including when power is shut off to the unit. - To recall, press and release button, most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress and hold button longer than 5 seconds. Page 9 RED LED Flash Code 2 Off Heartbeat1 Continuous Rapid Flash 1 2 3 4 5 6 7 8 9 10 11 12 13 Note - 1 Note - 2 Note - 3 TABLE 5 (-03 Integrated Control) Diagnostic Codes / Status of Furnace No power to control or board fault detected Normal Operation - Idle, Continuous Fan, Cool Call For Heat / Burner Operation Reverse Line Voltage Polarity Improper Earth Ground Burner failed to light, or lost flame during heat demand Low Flame Signal - check flame sensor Watchguard - burner failed to light, exceeded maximum number of retries or recycles. Not Used Primary or Secondary Limit Open or Watchguard Mode - Limit Switch Open longer than 3 minutes Rollout Switch Open Pressure Switch failed to close or opened during heat demand Watchguard - Pressure Switch opened 5 times during one heat demand Pressure Switch stuck closed prior to activation of combustion air inducer Flame Sensed without gas valve energized Low Line Voltage Notes A "Heartbeat" is indicated by a "Slow Flash" - 1 sec on 1 sec off, repeating Error codes are indicated by a "rapid flash" - the LED flashes X times at ½ second on ½ second off, remains off for 3 seconds then repeats. Last 10 error codes are stored in memory including when power is shut off to the unit. - To recall, pressand release button, most recent will be displayed first, LED off for 3 sec, then next error code is displayed, etc. To clear error codes, depress and hold button longer than 5 seconds. Page 10 1 ON OFF Pre -Purge DEMAND CAI IGNITOR GAS VALVE INDOOR BLOWER ELECTRONIC IGNITION 15 34 38 80 Ignitor Warm-up Trial for Ignition Blower "On"* Delay 5 SEC Post Purge *Blower on time will be 30 seconds after flame is sensed. Blower off time will depend on "OFF TIME" Setting. FIGURE 4 Fan Time Control Heating Fan On Time The fan on time of 30 seconds is not adjustable. Heating Fan Off Time Fan off time (time that the blower operates after the heat demand has been satisfied) can be adjusted by moving the jumper to a different setting. The unit is shipped with a factory fan off setting of 90 seconds. For customized comfort, monitor the supply air temperature once the heat demand is satisfied. Note the supply air temperature at the instant the blower is de-energized. Adjust the fan-off delay to achieve a supply air temperature between 90° - 110° at the instant the blower is de-energized. (Longer delay times allow for lower air temperature, shorter delay times allow for higher air temperature). See figure 5. Cooling Fan On Time The fan on time is 2 seconds and is not adjustable. Cooling Fan Off Time The control has a 45 second fan off delay after cooling demand has been met. This delay is factory set and not adjustable. HEAT FAN-OFF TIME IN SECONDS NO JUMPER To adjust fan-off timing, reposition jumper across pins to achieve desired setting. 60 Second off Time 90 Second off Time 120 Second off Time 180 Second off Time 60 90 120 180 60 90 120 180 60 90 120 180 60 90 120 180 FIGURE 5 Page 11 HEATING COMPONENTS Flue Transition Pressure Switch Gaskets Rollout Switches Ignitor Sensor Orifice Plate Combustion Air Inducer Collector Box Manifold And Gas Valve FIGURE 6 5. Flame Rollout Switches (Figure 6) Flame rollout switch (S47) is a high temperature limit. Each furnace is equipped with two identical switches. The limit is a N.C. SPST manual-reset limit connected in series with the integrated control A92. When S47 senses rollout, the integrated control immediately stops ignition and closes the gas valve. If unit is running and flame rollout is detected, the gas valve will close and integrated control will be disabled. Rollout can be caused by a blocked heat exchanger, blocked flue or lack of combustion air. The switch has a factory setpoint of 210°F and cannot be adjusted. To manually reset a tripped switch, push the reset button located on the control. 6. Primary Limit Control The primary limit on ML180UHE(X) units is located in the heating vestibule panel under the combustion air inducer. See figure 7. When excess heat is sensed in the heat exchanger, the limit will open. If the limit is open, the integrated control energizes the supply air blower and closes the gas valve. The limit automatically resets when unit temperature returns to normal. The switch must reset within three minutes or SureLight® control will go into Watchguard for one hour. The switch is factory set and cannot be adjusted. The switch may have a different setpoint for each unit model number. If limit switch must be replaced, refer to Lennox ProductZone repair parts list. Primary Limit Under Combustion Air Inducer Primary Limit FIGURE 7 7. Flame Sensor (Figure 6) A flame sensor is located on the left side of the burner support. The sensor is mounted on the flame rollout plate and the tip protrudes into the flame envelope of the left-most burner. The sensor can be removed for service (clean with steel wool) without removing any part of the burners. During operation, flame is sensed by current passed through the flame and sensing electrode. The integrated control allows the gas valve to remain open as long as flame signal is sensed. A microamp DC meter is needed to check the flame signal on the integrated control. Page 12 Flame (microamp) signal is an electrical current which passes from the integrated control to the sensor during unit operation. Current passes from the sensor through the flame to ground to complete a safety circuit. To Measure Flame Signal - Integrated Control: Use a digital readout meter capable of reading DC microamps. See figure 8 and table 6 for flame signal check. 1 - Set the meter to the DC amps scale. 2 - Turn off supply voltage to control. 3 - Remove sensor wire from integrated control. 4 - Connect (-) lead to flame sensor wire. 5 - Connect (+) lead to Terminal FS on integrated control. 6 - Turn supply voltage on and close thermostat contacts to cycle system. 7 - When main burners are in operation for two minutes, take reading. TABLE 6 Flame Signal in Microamps Normal Low Drop Out 1.5 or greater 0.5 - 1.4 0.4 or less Measuring Flame Signal (Typical Furnace and Control) Flame Sensor Remove Sensor Wire from Integrated Control and Connect Alligator Clip (-) to Flame Sensor Lead Flame Sensor Wire Integrated Control Flame Sensor Terminal (+) (+) To Control Sensor Terminal Remove Sensor Wire from Integrated Control and Connect Alligator Clip (+) to Terminal on Control FIGURE 8 DIGITAL METER Set dial to measure dc microamps Red Collar Indicates Positive Lead (+) (-) To flame sensor Page 13 8. Gas Valve (Figure 6) The ML180UHE(X) uses an internally redundant gas valve to assure safety shut-off. If the gas valve must be replaced, the same type valve must be used. 24VAC terminals and valve switch are located on the valve. All terminals on the gas valve are connected to wires from the integrated control. 24V applied to the terminals energizes the valve. Inlet and outlet pressure taps are located on the valve. A regulator adjustment screw is located on the valve. LPG changeover kits are available from Lennox. Kits include burner orifices and a gas valve regulator spring. 9. Combustion Air Inducer (B6) All ML180UHE(X) units use a combustion air inducer to move air through the burners and heat exchanger during heating operation. The blower uses a 120VAC motor. The motor operates during all heating operation and is controlled by integrated control A92. The inducer also operates for 15 seconds before burner ignition (pre-purge) and for 5 seconds after the gas valve closes (post-purge). A pressure switch mounted on the combustion air inducer orifice plate is used to prove inducer operation. The combustion air inducer orifice will be different for each model. See table 7 for orifice sizes. The switch monitors air pressure in the inducer housing. During normal operation, the pressure in the housing is negative. If pressure becomes less negative (signifying any obstruction in the flue) the pressure switch opens. When the pressure switch opens, the integrated control (A92) immediately de-energizes the gas valve to prevent burner operation. TABLE 7 Model C.A.I. Orifice Size 045E36A 1.063" 070E36B 1.316" 090E48B, 090E60C 1.531" 110E60C 1.690" 135E60D 1.940" 10. Ignitor (Figure 6) The nitride ignitor used on ML180UHE units is made from a proprietary ceramic material. To check ignitor, measure its resistance and voltage. A value of 39 to 70 ohms indicates a good ignitor. Voltage to the ignitor should be 120VAC. See figure 9 for resistance, and voltage check. NOTE - The ML180UHE(X) furnace contains electronic components that are polarity sensitive. Make sure that the furnace is wired correctly and is properly grounded. Page 14 IGNITOR CHECKS Test 1 Check ignitor circuit for correct resistance. Remove 4-pin plug from control. Check ohms reading across terminals 2 and 4. The reading should be between 39 and 70 ohms. If value is correct, this is the only test needed. If the reading on the meter is not correct, (0 or infinity) then a second test is needed. Meter (set to ohms) Test 2 Check ignitor for correct resistance. Separate the 2-pin jack-plug near the manifold and check resistance of ignitor at the plug. Reading should be between 39 and 70 ohms. If the reading is correct, then the problem is with the wiring between the jack-plug and the control. If reading is not correct, the issue is the ignitor. Meter (set to ohms) Test 3 Check ignitor for correct voltage Insert meter probes into terminals 2 and 4 (use small diameter probes in order not to damage plug). Check voltage during 20 second ignitor warm up period. Voltage should read 120 volts + 10%. If voltage reads below these values, check for correct supply voltage to furnace. Meter (set to ohms) FIGURE 9 Integrated Control Board Detail Page 15 11. Combustion Air Inducer Pressure Switch (S18) ML180UHE(X) series units are equipped with a combustion air pressure switch located on the combustion air inducer orifice bracket. The switch is connected to the combustion air inducer housing by means of a flexible silicone hose. It monitors negative air pressure in the combustion air inducer housing. The switch is a single-pole single-throw proving switch electrically connected to the furnace control. The purpose of the switch is to prevent burner operation if the combustion air inducer is not operating or if the flue becomes obstructed. On start-up, the switch senses that the combustion air inducer is operating. It closes a circuit to the integrated control when pressure inside the combustion air inducer decreases to a certain set point. Set points vary depending on unit size. See table 8. The pressure sensed by the switch is negative relative to atmospheric pressure.If the flue becomes obstructed during operation, the switch senses a loss of negative pressure (pressure becomes more equal with atmospheric pressure) and opens the circuit to the integrated control and gas valve. A bleed port on the switch allows relatively dry air in the vestibule to purge switch tubing, to prevent condensate build up. TABLE 8 inches wc Unit Make Break + 0.05 045E36A-1, -2, -54 -0.75 -0.65 070E36B-1, -2 -0.83 -0.68 070E36B-54 -0.85 -0.70 090E48B, 090E60C-1, -2 -0.80 -0.65 090E48B-54 -0.85 -0.70 110E60C-1, -2 -0.83 -0.68 110E60C-54 -0.85 -0.70 135E60D-1, -2, -54 -0.80 -0.65 The switch is factory set and is not field adjustable. It is a safety shut-down control in the furnace and must not be bypassed for any reason. If switch is closed or by-passed, the integrated control will not initiate ignition at start up. Troubleshooting See figure 10 for measuring operating pressure and checking resistance in the pressure switch. MULTI-METER SET TO MEASURE OHMS Remove tubing from CAI and insert "Tee" and additional tubing. To Pressure Switch + - or Field Provided Tubing To CAI Port High Low FIGURE 10 Page 16 Multiple Venting The ML180UHE(X) furnace can vent in multiple positions. See figure 11. The make up box may be removed and the combustion air inducer may be rotated clockwise or counterclockwise 90° to allow for vertical or horizontal vent discharge in a vertical or horizontal cabinet position. Remove the four mounting screws, rotate the assembly (assembly consists of orifice plate, proving switch, gasket and combustion air inducer), then reinstall the mounting screws. See unit Installation Instructions for more detail. IMPORTANT The combustion air pressure switch must be moved for horizontal discharge air left position. Pressure Switch vent pipe Vent Pipe Collector Box vent pipe flue transition vent pipe AIR FLOW vent pipe flue transition Collector Box pressure switch vent pipe vent pipe Pressure Switch AIR FLOW AIR FLOW In all positions route the wires away from moving parts and the heat of the inducer motor to prevent damage to the wires. The pressure switch must be installed above the CAI to prevent moisture from collecting in the hoses or switch. FIGURE 11 Page 17 12. Blower Motor IMPORTANT Each blower is statically and dynamically balanced as an assembly before installation in the unit. ML180UHE units are equipped with a constant torque ECM motor. It has a DC motor coupled to an electronic control module both contained in the same motor housing. The motor is programmed to provide constant torque at each of the five selectable speed taps. Each tap requires 24 volts to energize. Input Voltage Requirements The circuit is designed to be operated with AC voltage. To enable a tap requires 12 to 33VAC. Expected current draw will be less than 20mA. Troubleshooting Troubleshooting the motor is an easy process. Follow steps below. 1 - Shut off power to unit. 2 - Remove input plugs P48 and P49 from motor. See figure 14 for troubleshooting procedure. If correct voltage is present in tests 1 and 2 and motor is not operating properly, replace motor. The motor is not field repairable. If replacing the indoor blower motor or blower wheel is necessary, placement is critical. The blower wheel must be centered in the blower housing as shown in figure 12. When replacing the indoor blower motor the set screw must be aligned and tightened with the motor shaft as shown in figure 13. BLOWER WHEEL REPLACEMENT Center Blower Wheel in Blower Housing FIGURE 12 ALIGN AND TIGHTEN SET SCREW WITH FLAT SIDE OF MOTOR SHAFT Housing Hub Set Screw Motor Shaft FIGURE 13 Page 18 P49 5 4 3 2 1 Multi-Meter (set to VAC) 12 0 Test 1 N G L C P48 Turn on power to unit. Check for 120 volts across terminals "L" and "N" on input plug P48. If voltage is present continue stream of plug P48 and proceed to test 3. Multi-Meter (set to VAC) 120 Test 3 (if necesssary) Check for 120 volts across terminals "CIRC" and "Neutrals" on the integrated control. If voltage is present, problem is with the harness. If voltage is not present problem may be may be with the integrated control. P49 5 4 3 2 1 Multi-Meter (set to VAC) 24 Multi-Meter (set to VAC) 24 N G L C P48 Test 2 Switch thermostat to CONTINUOUS FAN MODE. Check for 24 volts across terminal "C" on inpult plug P48and speed tap used for continuous fan. (1, 2, 3, 4 or 5) on input plug P49. If 24 volts is not present problem may be up stream of plug P49. Proceed to test 4. Test 4 (if necessary) lem is with the harness. If voltage is not present problem may be may be with the integrated control FIGURE 14 Page 19 Replacing the Motor Module 1 - Disconnect electrical power to unit. 2 - Remove unit access panel. 3 - Unplug the two harnesses from the motor control module. See figure 15. Unplug the Two Harness Connection TWO HARNESS CONNECTIONS MOTOR MOTOR CONTROL MODULE FIGURE 15 4 - Remove the two hex head bolts securing the motor control module to the motor (see figure 16). Remove the Hex Head Bolts REMOVE BOTH HEX HEAD BOLTS FIGURE 16 5 - Slide the motor control module away from the motor to access and disconnect the internal three wire connector. It is not necessary to remove blower motor itself. Set both hex head bolts aside. Testing the Motor (Figure17) If any motor fails the below tests, do not install the new control module. The motor is defective and it also must be replaced. The new control can fail if placed on a defective motor. 1 - Using an ohmmeter check the resistance from any one of the motor connector pins to the aluminum end plate of the motor. This resistance should be greater than 100k ohms. 2 - Check the resistances between each of the three motor connector pins. These should all read approximately the same resistance within an ohm. 3 - Check to see if the blower wheel spins freely. Motor Test FIGURE 17 TABLE 9 Scale Measurement range in ohms words 2 M two megohm-two million ohms 0 - 2,000,000 200 K two hundred kilo-ohm-two hundred thousand ohms 0 - 200,000 20 K twenty kilo-ohm-twenty thou- 0 - 20,000 sand ohms 2 K two kilo-ohm two-thousand 0 - 2,000 ohms 200 two hundred ohms 0 - 200 Motor Module Installation All replacement motor control modules look similar; however, each module is designed for a specific motor size. It is very important to make sure that you are using the correct replacement motor control module. USE OF THE WRONG MOTOR CONTROL MODULE MAY RESULT IN UNEXPECTED UNIT OPERATION. 1 - Verify electrical power to unit is disconnected. 2 - Connect three-wire harness from motor to control module. 3 - Mount new motor control module to motor using two hex head bolts removed in figure 10. Torque bolts to 22 inch pounds or 1/16th clock wise turn. 4 - Reconnect the two harnesses to the motor control module. 5 - The electrical connectors of the motor should be facing down to form a drip loop (figure12). This will directs moisture away from the motor and its electric connections on the motor Drip Loop BACK OF CONTROL MODULE CONNECTOR ORIENTATION BETWEEN 4 AND 8 O'CLOCK DRIP LOOP FIGURE 18 Page 20 II- PLACEMENT AND INSTALLATION Make sure unit is installed in accordance with installation instructions and applicable codes. III- START-UP A- Heating Start-Up WARNING Shock and burn hazard. ML180UHE(X) units are equipped with a hot surface ignition system. Do not attempt to light manually. Gas Valve Operation MANIFOLD PRESSURE ADJUSTMENT SCREW MANIFOLD PRESSURE OUTLET PORT INLET PRESSURE PORT GAS VALVE SHOWN IN ON POSITION FIGURE 19 1 - STOP! Read the safety information at the beginning of this section. 2 - Set the thermostat to the lowest setting. 3 - Turn off all electrical power to the unit. 4 - This furnace is equipped with an ignition device which automatically lights the burners. Do not try to light the burners by hand. 5 - Remove the upper access panel. 6 - Move gas valve switch to OFF position. Do not force. See figure 19. 7 - Wait five minutes to clear out any gas. If you then smell gas, STOP! Immediately call your gas supplier from a neighbor's phone. Follow the gas supplier's instructions. If you do not smell gas go to next step. 8 - Move gas valve switch to ON position. Do not force. See figure 19. 9 - Replace the upper access panel. 10 - Turn on all electrical power to to the unit. 11 - Set the thermostat to desired setting. NOTE - When unit is initially started, steps 1 through 11 may need to be repeated to purge air from gas line. 12 - If the appliance will not operate, follow the instructions "Turning Off Gas to Unit" and call the gas supplier. Turning Off Gas to Unit 1 - Set the thermostat to the lowest setting. 2 - Turn off all electrical power to the unit if service is to be performed. 3 - Remove the upper access panel. 4 - Move gas valve switch to OFF position. Do not force. See figure 19. 5 - Replace the upper access panel. B- Safety or Emergency Shutdown Disconnect main power to unit. Close manual and main gas valves. C- Extended Period Shutdown Turn off thermostat or set to "UNOCCUPIED" mode. Close all gas valves (both internal and external to unit) to guarantee no gas leaks into combustion chamber. Turn off power to unit. All access panels and covers must be in place and secured. IV-HEATING SYSTEM SERVICE CHECKS A- C.S.A. Certification All units are C.S.A. design certified without modifications. Refer to the ML180UHE(X) Installation Instruction. B- Gas Piping Gas supply piping should not allow more than 0.5"W.C. drop in pressure between gas meter and unit. Supply gas pipe must not be smaller than unit gas connection. Compounds used on gas piping threaded joints should be resistant to action of liquefied petroleum gases. C- Testing Gas Piping CAUTION If a flexible gas connector is required or allowed by the authority that has jurisdiction, black iron pipe shall be installed at the gas valve and extend outside the furnace cabinet. IMPORTANT In case emergency shutdown is required, turn off the main shut-off valve and disconnect the main power to unit. These controls should be properly labeled by the installer. WARNING Do not exceed 600 in-lbs (50 ft-lbs) torque when attaching the gas piping to the gas valve. 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 20. If the pressure is equal to or less than 0.5psig (14"W.C.), close the manual shut-off valve before pressure testing to isolate furnace from gas supply. Page 21 MANUAL MAIN SHUT-OFF VALVE WILL NOT HOLD NORMAL TEST PRESSURE 1/8 NPT PLUG ISOLATE GAS VALVE FURNACE CAP FIGURE 20 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. Do not use matches, candles, flame or any other source of ignition to check for gas leaks. D- Gas Pressure Adjustment Gas Flow (Approximate) TABLE 10 GAS METER CLOCKING CHART Seconds For One Revolution ML180UHE Unit Natuarl 1 cu ft Dial 2 cu ft Dial LP/Propane 1 cu ft Dial 2 cu ft Dial -045 80 160 200 400 -070 55 110 136 272 -090 41 82 102 204 -110 33 66 82 164 -135 27 54 68 136 Natural-1000 btu/cu ft LP-2500 btu/cu ft Furnace should operate at least 5 minutes before 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 10. If manifold pressure matches table 12 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. E- Supply and Manifold Pressure Supply Pressure Measurement 1 - Remove the threaded plug from the inlet side of the gas valve and install a field-provided barbed fitting. Connect to a test gauge to measure supply pressure. 2 - Start unit and allow 5 minutes for unit to reach steady state. 3 - After allowing unit to stabilize for 5 minutes, record supply pressure and compare to value given in table 12. Manifold Pressure Measurement 1 - Remove the threaded plug from the outlet side of the gas valve and install a field-provided barbed fitting. Connect to a test gauge to measure manifold 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 12. 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. F- Proper Combustion Furnace should operate a 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. The maximum carbon monoxide reading should not exceed 100 ppm. ML180UHE Unit -045 -070 -090 -110 -135 G- High Altitude TABLE 11 CO2% Nat 7.2 - 7.8 CO2% LP 7.5 - 9.0 The manifold pressure may require adjustment and combustion air pressure switch may need replacing to ensure proper combustion at higher altitudes. Refer to table 12 for manifold pressure and table 13 for pressure switch change and gas conversion kits. IMPORTANT For safety, shut unit off and remove manometer as soon as an accurate reading has been obtained. Take care to replace pressure tap plug. Page 22 Model Input Size 045 070 090 110 135 Gas Nat LP/Propane Nat LP/Propane Nat LP/Propane Nat LP/Propane Nat LP/Propane 0 - 2000 ft. 3.5 10.0 3.5 10.0 3.5 10.0 3.5 10.0 3.5 10.0 TABLE 12 Manifold Pressure Settings at all Altitudes 2001 -4500 ft . 4501 - 7500 ft. 7501 - 10,000 ft 3.2 3.0 3.5 10.0 10.0 10.0 3.2 2.8 3.5 10.0 10.0 10.0 3.2 2.7 3.5 10.0 9.6 10.0 3.5 3.0 3.5 10.0 9.6 10.0 3.5 2.9 3.5 10.0 9.6 10.0 Line Pressure in. wg. Min Max 4.5 13.0 11.0 13.0 4.5 13.0 11.0 13.0 4.5 13.0 11.0 13.0 4.5 13.0 11.0 13.0 4.5 13.0 11.0 13.0 TABLE 13 Pressure Switch and Gas Conversion Kits at all Altitudes Model Input Size High Altitude Pressure Switch Kit High Altitude Natuarl Gas Orifice Kit LP/Propane Oricifice Kit Natuarl Gas Orifice Kit 045 0-4500 ft 4501-7500 ft 7501-10,000 ft 7501-10,000 ft 0-7500 ft 7501-10,000 ft 0-7500 ft 070 80W52 80W51 110 80W52 80W51 090 No Change 80W52 80W51 73W37 11K49 11K44 73W81 110 80W57 80W52 135 80W52 80W51 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. Page 23 H- Proper Ground and Voltage A poorly grounded furnace can contribute to poor flame sense signal. Use the following procedure to check for ground and voltage to the integrated control. 1 - Measure the AC voltage between Line Neutral (spade terminals) and "C" terminal (low voltage terminal block) on the integrated control. See figure 21. A wide variation in the voltage between Line Neutral and "C" as a function of load indicates a poor or partial ground. Compare the readings to the table below. If the readings exceed the maximum shown in table 14, make repairs before operating the furnace. 2 - In addition, measure the AC voltage from Line Hot to Line Neutral (spade terminals) on the integrated control. See figure 22. This voltage should be in the range of 97 to 132 Vac. CHECK VOLTAGE BETWEEN LINE NEUTRAL AND LOW VOLTAGE "C" TERMINAL TABLE 14 Furnace Status Measurement VAC Expected Maximum Power on Furnace Idle 0.3 2 CAI/Ignitor Energized 0.75 5 Indoor Blower Energized Less than 2 10 CHECK VOLTAGE BETWEEN LINE HOT AND LINE NEUTRAL FIGURE 21 FIGURE 22 Page 24 V-TYPICAL OPERATING CHARACTERISTICS A-Blower Operation and Adjustment NOTE- The following is a generalized procedure and does not apply to all thermostat controls. 1 - Blower operation is dependent on thermostat control system. 2 - Generally, blower operation is set at thermostat subbase fan switch. With fan switch in ON position, blower operates continuously. With fan switch in AUTO position, blower cycles with demand or runs continuously while heating or cooling circuit cycles. 3 - Depending on the type of indoor thermostat, blower and entire unit will be off when the system switch is in OFF position. B-Temperature Rise (Figure 23) Temperature rise for ML180UHE(X) units 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. ° TEMPERATURE RISE Supply Duct Temperature ________ Return Duct Temperature _ _____ Temperature Rise = ________ C-External Static Pressure 1 - Tap locations shown in figure 24 . 2 - Punch a 1/4" diameter hole in supply and return air plenums. Insert manometer hose flush with inside edge of hole or insulation. Seal around the hose with permagum. Connect the zero end of the manometer to the discharge (supply) side of the system. On ducted systems, 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 blower motor speed to deliver the air desired according to the job requirements. For heating speed external static pressure drop must not be more than 0.5" W.C. For cooling speed external static pressure drop must not be more than 0.8" W.C. 4 - Seal the hole when the check is complete. EXTERNAL STATIC PRESSURE Supply Duct Static ________ Return Duct Static + _____ Total Duct Static = ________ (dry coil) SUPPLY AIR Temperatures RETURN AIR FIGURE 23 Supply Air Duct Static or Return Air FIGURE 24 Page 25 VI-MAINTENANCE At the beginning of each heating season, and to comply with the Lennox Limited Warranty, your system should be checked by a licensed professional technician (or equivalent) as follows: IMPORTANT If a highefficiency filter is being installed as part of this system to ensure better indoor air quality, the filter must be properly sized. Highefficiency filters have a higher static pressure drop than standardefficiency glass/foam filters. If the pressure drop is too great, system capacity and performance may be reduced. The pressure drop may also cause the limit to trip more frequently during the winter and the indoor coil to freeze in the summer, resulting in an increase in the number of service calls. Before using any filter with this system, check the specifications provided by the filter manufacturer against the data given in the appropriate Lennox Product Specifications bulletin. Additional information is provided in Service and Application Note ACC002 (August 2000). WARNING Fire Hazard. Use of aluminum wire with this product may result in a fire, causing property damage, severe injury or death. Use copper wire only with this product. WARNING Failure to use properly sized wiring and circuit breaker may result in property damage. Size wiring and circuit breaker(s) per Product Specifications bulletin (EHB) and unit rating plate. 1 - Check wiring for loose connections, voltage at indoor unit and amperage of indoor motor. 2 - Check the condition of the belt and shaft bearings if applicable. 3 - Inspect all gas pipe and connections for leaks. 4 - Check the cleanliness of filters and change if necessary (monthly). Furnace Cabinet Width A - 14-1/2" B - 17-1/2" C - 21" D - 24-1/2" TABLE 15 Filter Size Side Return Bottom Return 16 X 25 X 1 (1) 14 X 25 X 1 (1) 16 X 25 X 1 (1) 16 X 25 X 1 (1) 16 X 25 X 1 (1) 20 x 25 x 1 (1) 16 X 25 X 1 (2) 24 x 25 x 1 (1) 5 - Check the condition and cleanliness of burners and heat exchanger and clean if necessary. 6 - Check the cleanliness of blower assembly and clean the housing, blower wheel and blower motor if necessary . The blower motors are prelubricated for extended bearing life. No further lubrication is needed. 7 - Inspect the combustion air inducer and clean if necessary. 8 - Evaluate the heat exchanger integrity by inspecting the heat exchanger per the AHRI heat exchanger inspection procedure. This procedure can be viewed at www.ahrinet.org 9 - Ensure sufficient combustion air is available to the furnace. Fresh air grilles and louvers (on the unit and in the room where the furnace is installed) must be properly sized, open and unobstructed to provide combustion air. 10 - Inspect the furnace venting system to make sure it is in place, structurally sound, and without holes, corrosion, or blockage. Vent system must be free and clear of obstructions and must slope upward away from the furnace . Vent system should be installed per the National Fuel Gas Code. 11 - Inspect the furnace return air duct connection to ensure the duct is sealed to the furnace. Check for air leaks on supply and return ducts and seal where necessary. 12 - Check the condition of the furnace cabinet insulation and repair if necessary. 13 - Perform a complete combustion analysis during the furnace inspection to ensure proper combustion and operation. Consult Service Literature for proper combustion values. 14 - Verify operation of CO detectors and replace batteries as required. Perform a general system test. Turn on the furnace to check operating functions such as the start-up and shut-of operation. 1 - Check the operation of the ignition system, inspect and clean flame sensor. Check microamps before and after. Check controls and safety devices (gas valve, flame sensor, temperature limits). Consult Service Manual for proper operating range. Thermal Limits should be checked by restricting airflow and not disconnecting the indoor blower. For additional details, please see Service and Application Note H049. 2 - Verify that system total static pressure and airflow settings are within specific operating parameters. Page 26 3 - Clock gas meter to ensure that the unit is operating at the specified firing rate. Check the supply pressure and the manifold pressure. On two-stage gas furnaces check the manifold pressure on high fire and low fire. If manifold pressure adjustment is necessary, consult the Service Literature for unit specific information on adjusting gas pressure. Not all gas valves are adjustable. Verify correct temperature rise. Cleaning the Heat Exchanger and Burners NOTE - Use papers or protective covering in front of the furnace during cleaning. 1 - Turn off both electrical and gas power supplies to furnace. 2 - Remove flue pipe and top cap (some applications top cap can remain) from the unit. 3 - Label the wires from gas valve, rollout switches, primary limit switch and make-up box then disconnect them. 4 - Remove the screws that secure the combustion air inducer/ pressure switch assembly to the collector box. Carefully remove the combustion air inducer to avoid damaging blower gasket. If gasket is damaged, it must be replaced to prevent leakage. 5 - Remove the collector box located behind the combustion air inducer. Be careful with the collector box gasket. If the gasket is damaged, it must be replaced to prevent leakage. 6 - Disconnect gas supply piping. Remove the four screws securing the burner manifold assembly to the vestibule panel and remove the assembly from the unit. BURNER, COMBUSTION AIR INDUCER ASSEMBLY & HEAT EXCHANGER REMOVAL Flue Transition Pressure Switch Gasket Rollout Switches Ignitor Flame Sensor Orifice Plate Collector Box Combustion Air Inducer Heat Exchanger Retention Rings Manifold And Gas Valve FIGURE 25 Cross Over Page 27 7 - NOX units only - Remove screw securing NOX insert. Remove NOX insert. See figure 26. 8 - Remove screws from both sides, top and bottom of vestibule panel. 9 - Remove heat exchanger. It may be necessary to spread cabinet side to allow more room. If so, remove five screws from the left side or right side of cabinet. See figure 27. 10 - Backwash using steam. Begin from the burner opening on each clam. Steam must not exceed 275°F. 11 - To clean burners, run a vacuum cleaner with a soft brush attachment over the face of burners. Visually inspect inside the burners and crossovers for any blockage caused by foreign matter. Remove any blockage. Figure 25 shows burner detail. 12 - To clean the combustion air inducer visually inspect and using a wire brush clean where necessary. Use compressed air to clean off debris and any rust. 13 - Reinstall heat exchanger in vestibule. (Replace the five screws in the cabinet from step 10 if removed). 14 - NOx units only - Replace NOx inserts. 15 - Reinstall collector box and combustion air assembly. Reinstall all screws to the collector box and combustion air inducer. Failure to replace all screws may cause leaks. Inspect gaskets for any damage and replace if necessary. 16 - Reinstall burner box and manifold assembly. 17 - Reconnect all wires. 18 - Reconnect top cap and vent pipe to combustion air inducer outlet. 19 - Reconnect gas supply piping. 20 - Turn on power and gas supply to unit. 21 - Set thermostat and check for proper operation. 22 - Check all piping connections, factory and field, for gas leaks. Use a leak detecting solution or other preferred means. 23 - If a leak is detected, shut gas and electricity off and repair leak. CAUTION Some soaps used for leak detection are corrosive to certain metals. Carefully rinse piping thoroughly after leak test has been completed. Do not use matches, candles, flame or other sources of ignition to check for gas leaks. 24 - Repeat steps 24 and 26 until no leaks are detected. 25 - Replace access panel. NOx INSERTS NOx Insert FIGURE 26 Remove 5 screws if necessary (either side of cabinet) 1 2 3 4 5 FIGURE 27 Page 28 VII- Wiring and Sequence of Operation Schematic Wiring Diagram and Sequence of Operation 3 10 1 5 8 6 5 2 7 9 4 1 1 - Line voltage is applied to L1 and N. the T1 low voltage transformer is energized, and line voltage is applied to B3 indoor blower. 2 - S47 rollout switch(es) must be closed in order for 24V from transformer to be output on integrated control "R" to power thermostat. 3 - When there is a call for heat, W1 of the thermostat energizes W of the furnace control with 24VAC. 4 - A92 integrated control runs a self-check. S10 primary limit and S21 secondary limit contacts are found to be closed. Call for heat can continue. 5 - A92 integrated control energizes B6 combustion air inducer. S18 combustion air pressure switch closes . Once S18 closes, a 15-second pre-purge follows. 6 - A92 integrated control energizes R33 ignitor. A 20-second warm-up period begins. 7 - GV1 gas valve opens for a 4-second trial for ignition 8 - Flame is sensed, gas valve remains open for the heat call. 9 - After 30-second delay (from flame sensed), A92 integrated control applies 24vVAC to Heat speed of B3 indoor blower. 10 - When heat demand is satisfied, W1 of the indoor thermostat de-energizes W of A92ignition control which de-energizes GV1 gas valve. B6 combustion air inducer continues a 5-second post-purge period, and B3 indoor blower completes a selected OFF time delay. Page 29 HEATING SEQUENCE OF OPERATION NORMAL HEATING MODE POWER ON CONTROL SELF-CHECK OKAY? ABNORMAL HEATING MODE GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. NO INDOOR BLOWER DELAY OFF. LED SLOW FLASH (RESET CONTROL BY TURNING MAIN POWER OFF.) YES IS POLARITY CORRECT? NO LED FLASHES CODE 1 - POLARITY REVERSED. YES IS THERE A PROPER GROUND? YES NO IS VOLTAGE ABOVE 70 VOLTS? NO LED FLASHES CODE 2 - IMPROPER GROUND. LED FLASHES CODE 13 - LOW LINE VOLTAGE. CONTROL WILL NOT RESPOND TO A CALL FOR HEATING UNTIL VOLTAGE RISES ABOVE 75 VOLTS. YES ROLLOUT SWITCH CLOSED? YES LED FLASHES CODE 8 - ROLLOUT SWITCH OPEN. NO GAS VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR BLOWER ON. SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES AND POWER IS RESET OR T'STAT IS INTERRUPTED FOR MINIMUM OF 1 SECOND. BURNER OFF? NO LED FLASHES CODE 12 - FLAME SENSED WITHOUT GAS VALVE ENERGIZED. (Flame sensed without gas valve energized) GAS VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR BLOWER ON HEATING SPEED. YES NO NORMAL OPERATION: LED SLOW FLASH YES THERMOSTAT CALLS FOR HEAT: LED SLOW FLASH YES LED FLASHES CODE 7 - PRIMARY LMIT OPEN. COMBUSTION AIR INDUCER OFF.INDOOR BLOWER ON NO 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 CONTINUED NEXT PAGE LED FLASHES CODE 11 - PRESSURE SWITCH CLOSED. NO GAS VALVE OFF COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF WITH DELAY. (Sequence holds until pressure switch opens or thermostat resets control.) LED FLASHES CODE 9 - PRESSURE SWITCH FAILED NO TO CLOSE OR OPENED DURING HEAT DEMAND. PRESSURE SWITCH IS IN WATCHGUARD MODE. GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF WITH DELAY. IS 5-MINUTE RESET PERIOD COMPLETE? YES Page 30 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? NO NO NO NO IS VOLTAGE ABOVE 70 VOLTS? YES LED FLASHES CODE 13 LOW LINE VOLTAGE. ONCE VOLTAGE IS ABOVE 75 VOLTS, HEATING SEQUENCE RESTARTS. GAS VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR BLOWER OFF. HAS CONTROL FAILED TO SENSE FLAME FOR NO FIVE CONSECUTIVE TRIES DURING A SINGLE HEAT DEMAND? LED SIGNAL WATCHGUARD FAILURE CODE WATCHGUARD MODE. GAS VALVE OFF. COMBUSTION AIR INDUCER OFF. INDOOR BLOWER OFF WITH DELAY IS 60-MINUTE RESET PERIOD COMPLETE? HAS CONTROL RESET IGNITION SEQUENCE FOUR TIMES? YES YES NO YES YES FLAME SIGNAL 1.5 MICROAMPS OR GREATER? YES NO LED FLASHES CODE 4 - LOW FLAME SIGNAL. (Does not affect operation of control) LED FLASHES CODE 7 - PRIMARY LIMIT OPEN. GAS VALVE, COMB. AIR INDUCER INDOOR BLOWER ON AFTER 30-SECOND DELAY YES PRIMARY LIMIT SWITCH CLOSED? YES NAL LIMIT SWITCH LED FLASHES CODE 7 - PRIMARY LIMIT OPEN GAS VALVE DE-ENERGIZED. NO COMBUSTION AIR INDUCER DE-ENERGIZED. INDOOR BLOWER ON UNTIL SWITCH CLOSES. LIMIT SWITCH CLOSED? YES OPEN UNTIL MAIN POWER IS INTERRUPTED OR T'STAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM. 60-MINUTE HAS PRIMARY LIMIT RESET TIME EXCEEDED 3 MINUTES? YES RIOD STARTS AT TIME LIMIT CLOSES. IS 60-MIN. PERIOD COMPLETE? NO ROLLOUT SWITCH CLOSED? YES COMBUSTION AIR PRESSURE SWITCH CLOSED? NO LED FLASHES CODE 8 - ROLLOT SWITCH OPEN. GAS VALVE POWER OFF. COMBUSTION AIR INDUCER POWER ON. INDOOR BLOWER ON SEQUENCE HOLDS UNTIL ROLLOUT SWITCH IS RESET AND MAIN POWER IS INTERRUPTED OR THERMOSTAT IS CYCLED OFF/ON FOR 1 SEC. MINIMUM. NO YES THERMOSTAT DEMAND SATISFIED. YES LED SLOW FLASH. 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. HAS PRESSURE SWITCH OPENED 5 TIMES IN THE SAME HEAT DEMAND? LED FLASHES CODE 10 NO YES 1 HR PRESSURE GAS VALVE DE-ENERGIZED. COMBUSTION AIR INDUCER ON. INDOOR BLOWER OFF WITH DELAY. HAS CAB PRESSURE SWITCH CLOSED SWITCH WATCHGUARD MODE WITHIN 2.5 MINUTES? NO YES 5-MINUTE PRESSURE SWITCH WATCHGUARD MODE. Page 31 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 NO IS VOLTAGE ABOVE 70 VOLTS? YES ROLLOUT SWITCH MONITORED CONTINUOUSLY. IS ROLLOUT SWITCH CLOSED? YES NO NO NO NO 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. LED FLASHES CODE 2 IMPROPER GROUND CONTROL WILL CONTINUE TO CALL FOR COOLING IN THIS CONDITION. LED FLASHES CODE 1 POLARITY REVERSED CONTROL WILL CONTINUE TO CALL FOR COOLING IN THIS CONDITION. LED FLASHES CODE 13 LOW VOLTAGE. CONTROL WILL CONTINUE TO CALL FOR COOLING IN THIS CONDITION. LED FLASHES CODE 8 ROLLOUT SWITCH OPEN. GAS VALVE OFF. COMBUSTION AIR INDUCER ON. INDOOR BLOWER ON. SEQUENCE HOLDS UNTIL ROLLOUT SWITCH CLOSES AND MAIN POWER IS INTERRUPTED OR THERMOSTAT 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 32 CONTINUOUS FAN SEQUENCE OF OPERATION LED: SLOW FLASH RATE REMAINS UNCHANGED THROUGHOUT SEQUENCE. MANUAL FAN SELECTION MADE AT THERMOSTAT. CONTROL (G) ENERGIZES SYSTEM FAN AT FAN SPEED. EAC TERMINAL IS ENERGIZED. THERMOSTAT CALLS FOR HEAT (W). NO YES THERMOSTAT CALLS FOR COOLING. YES NO SYSTEM FAN SWITCHED TO COOL SPEED. EAC TERM. REMAINS ON. SYSTEM FAN CONTINUES FAN SPEED WITHOUT INTERRUPTION. EAC TERMINAL REMAIN ON. HUM TERMINAL IS ENERGIZED WITH COMBUSTION AIR BLOWER. THERMOSTAT OPENS. MANUAL FAN SELECTION MADE AT THERMOSTAT. CONTROL (G) ENERGIZES SYSTEM FAN AT FAN SPEED. EAC TERM. ENERGIZED. SYSTEM FAN SWITCHES TO HEAT SPEAD AFTER 30 SECOND DELAY. EAC AND HUM TERMINAL REMAIN ON. THERMOSTAT OPENS. HUM. TERMINAL OFF AFTER POST PURGE BY COMBUSTION AIR BLOWER. SYTEM FAN SWITCHES TO FAN SPEED AFTER BLOWER OFF DELAY. EAC CONTINUES WITHOUT INTERRUPTION. Page 33Adobe InDesign 16.1 (Windows) Adobe PDF Library 15.0