Lennox ML180UHT, Installation Instructions Manual

Page 1: ...r death WARNING Improper installation adjustment alteration service or maintenance can cause property damage person al injury or loss of life Installation and service must be performed by a licensed p...

Page 2: ...ne side return air See Blower Performance Tables for additional informa tion 1 Bottom Return Air Opening GAS PIPING INLET Either Side Side Return Air Opening Either Side 1Bottom Return Air Opening FLU...

Page 3: ...LP Propane is a regulated manufactured gas a Wobbe number is not required to determine acceptability For propane installations the acceptable heating value range is 93 2 mj m3 2500 btu ft3 5 NOTE Lenn...

Page 4: ...system as possible The furnace should also be located close to the chimney or vent termination point Do not install the furnace where drafts might blow direct ly into it This could cause improper com...

Page 5: ...t 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...

Page 6: ...ngular air ducts shall be no less than 75 mm 3 inches In calculating free area the blocking effect of louvers grilles or screens must be considered If the design and free area of protective cov ering...

Page 7: ...ss may be placed under each corner of the furnace as ap propriate to the application The ML180UHT gas furnace can be installed as shipped in either the upflow position or the horizontal position Selec...

Page 8: ...ght in through the bottom or either side of the furnace installed in an upflow application If the furnace is installed on a platform with bottom return make an airtight seal between the bottom of the...

Page 9: ...ust not extend beyond the markings on the furnace cabinet 2 To minimize pressure drop the largest opening height possible up to 356 mm 14 in is preferred FURNACE FRONT AIR FLOW 1 Unit side return air...

Page 10: ...ove installations are shown in figure 10 This furnace may be installed in either an attic or a crawl space Either suspend the furnace from roof rafters or floor joists as shown in figure 11 or install...

Page 11: ...33 21 405 X 635 X 25 1 16 X 25 X 1 508 X 635 X 25 1 20 X 25 X 1 D 622 24 1 2 405 X 635 X 25 2 16 X 25 X 1 610 X 635 X 25 1 24 X 25 X 1 Duct System Use industry approved standards to size and install t...

Page 12: ...nd or make up box as needed per the follow ing steps See figures 14 through 20 1 Remove the four mounting screws figure 13 which secure the combustion air inducer pressure switch assembly to the orifi...

Page 13: ...excess wire and secure to the gas manifold Pressure Switch Vent Pipe Flue Transition Cover Plate Collector Box FLOW AIR HORIZONTAL RIGHT POSITION Side Vent Discharge FIGURE 18 FLOW AIR Pressure Switc...

Page 14: ...ee be used Drive one self drilling screw through the front and one through each side of the vent pipe and collar See figure 21 Install the first vent connector elbow at a minimum of six inches 152 mm...

Page 15: ...relined with suitable materials or replaced with a gas vent or chimney suitable for venting ML180UHT series units The chimney passageway must be checked periodically to ensure that it is clear and fre...

Page 16: ...ity listed in the common venting tables should be reduced by 20 the equivalent of two 90 elbows 0 80 x maximum common vent capacity The horizontal length of the offset shall not exceed 1 1 2 feet 46 m...

Page 17: ...ance Height H feet Lateral L feet Vent and Connector Diameter D inches 3 Inch 4 Inch 5 Inch 6 Inch Appliance Input Rating in Thousands of Btu Per Hour MIN MAX MIN MAX MIN MAX MIN MAX 6 0 0 78 0 152 0...

Page 18: ...1 21 50 33 89 47 142 64 220 2 22 53 35 96 49 153 66 235 3 24 55 36 102 51 163 68 248 20 1 21 54 33 99 46 157 62 246 2 22 57 34 105 48 167 64 259 3 23 60 35 110 50 176 66 271 30 1 20 62 31 113 45 181...

Page 19: ...em is venting properly step 3 return all doors widows exhaust fans fireplace damp ers and any other gas burning appliances to their pre vious mode of operation 7 If a venting problem is found during a...

Page 20: ...OFF VALVE With 1 8 in NPT Plugged Tap Shown NOTE BLACK IRON PIPE ONLY TO BE ROUTED INSIDE OF CABINET FIGURE 24 GROUND JOINT UNION DRIP LEG MANUAL MAIN SHUT OFF VALVE GROUND JOINT UNION DRIP LEG MANUAL...

Page 21: ...rating for thermostat connections 5 Electrically ground the unit according to local codes NOTE The ML180UHT furnace contains electronic components that are polarity sensitive Make sure that the furna...

Page 22: ...tion System TERMINAL DESIGNATIONS HUM Humidifier 240VAC LINE Input 240VAC XFMR Transformer 240VAC EAC Electronic Air Cleaner 240VAC COOL Cool Speed 240VAC PARK1 PARK2 Dead terminals for alternate spee...

Page 23: ...Page 23 FIGURE 28 ML180UHT Schematic Wiring Diagram...

Page 24: ...does not get hot when there is no call for heat on units with an automatic ignition system WARNING If you do not follow these instructions exactly a fire or explosion may result causing property dama...

Page 25: ...tment Gas Flow To check for proper flow to combustion chamber deter mine Btu input from appliance rating plate Divide this input rating by the Btu per cubic foot of available gas Result is the require...

Page 26: ...t is located on the heating compartment vestibule panel The secondary limits if equipped are lo cated in the blower compartment attached to the back side of the blower These auto reset limits are fact...

Page 27: ...egrated control to begin the ignition sequence Service WARNING ELECTRICAL SHOCK FIRE OR EXPLOSION HAZARD Failure to follow safety warnings exactly could result in dangerous operation serious injury de...

Page 28: ...on Rings Cross Over Ignitor Sensor Rollout Switches Repair Parts List The following repair parts are available through independent Lennox dealers When ordering parts include the complete furnace model...