Summary of the content on the page No. 1
AIR FLOW
INSTALLATION
2011 Lennox Industries Inc.
INSTRUCTIONS
Dallas, Texas, USA
ML180UHE
®
MERIT SERIES GAS FURNACE
UPFLOW / HORIZONTAL AIR DISCHARGE
506810−01
06/2011
Supersedes 506732−01
Litho U.S.A.
THIS MANUAL MUST BE LEFT WITH THE
HOMEOWNER FOR FUTURE REFERENCE
This is a safety alert symbol and should never be ignored.
When you see this symbol on labels or in manuals, be alert
to the potential for personal injury or death.
WARNING
Improper installation, adjustment, alteration, service
o
Summary of the content on the page No. 2
Unit Dimensions − inches (mm) 1 NOTE − 60C and 60D units that require air volumes 3 −1/8 (79) over 1800 cfm (850 L/s) must have one of the following: 1. Single side return air with transition to accommodate 20 x 25 x 1 in. (508 x 635 x 25 mm) cleanable air D filter. (Required to maintain proper air velocity.) 2. Single side return with optional return air base. 3. Bottom return air. 4. Return air from both sides. SUPPLY AIR OPENING 5. Bottom and one side return air. See Blower Performance Tabl
Summary of the content on the page No. 3
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 Control Box (under (includes integrated control, combustion interlock switch and transformer) air inducer) Upper Access Panel Secondary Limits Blower Assembly Blower Access Panel Power Choke (4 and 5 Ton Only) FIGURE 1 Page 3
Summary of the content on the page No. 4
ML180UHE Gas Furnace CAUTION The ML180UHE unit is shipped ready for installation in the As with any mechanical equipment, personal injury upflow or horizontal right position (for horizontal left posi- can result from contact with sharp sheet metal tion the combustion air pressure switch must be moved) edges. Be careful when you handle this equipment. fueled by natural gas. A conversion kit (ordered separate- Certifications ly) is required for use in LP/Propane gas applications. The ML180UHE unit
Summary of the content on the page No. 5
Installed in Combination with a Cooling Coil This furnace design has not been CSA International certified for installation in mobile homes, recreational When this furnace is used with cooling units, it shall be vehicles, or outdoors. installed in parallel with, or on the upstream side of, cooling units to avoid condensation in the heating compartment. Use of Furnace as Construction Heater See figure 2. With a parallel flow arrangement, a damper (or Lennox does not recommend the use of ML180UHE u
Summary of the content on the page No. 6
Do not install the furnace where drafts might blow direct- information has been reprinted with permission from the ly into it. This could cause improper combustion and un- National Fuel Gas Code (ANSI-Z223.1). This reprinted ma- safe operation. terial is not the complete and official position of the ANSI on the referenced subject, which is represented only by the Do not block the furnace combustion air openings with standard in its entirety. clothing, boxes, doors, etc. Air is needed for pro
Summary of the content on the page No. 7
Unconfined Space Air from Inside An unconfined space is an area such as a basement or If the confined space that houses the furnace adjoins a large equipment room with a volume greater than 50 cubic space categorized as unconfined, air can be brought in by 3 feet (1.42 m ) per 1,000 Btu (.29 kW) per hour of the com- providing two permanent openings between the two bined input rating of all appliances installed in that space. spaces. Each opening must have a minimum free area of 1 2 This space al
Summary of the content on the page No. 8
EQUIPMENT IN CONFINED SPACE ALL AIR FROM OUTSIDE (Inlet Air from Crawlspace and Outlet Air to Ventilated Attic) CHIMNEY OR GAS VENT VENTILATION LOUVERS (Each end of attic) OUTLET AIR WATER FURNACE HEATER INLET VENTILATION AIR LOUVERS (For unheated crawl space) NOTE−The inlet and outlet air openings shall each have a free area of at least one square inch (645 2 mm ) per 4,000 Btu (1.17 kW) per hour of the total input rating of all equipment in the enclosure. FIGURE 4 EQUIPMENT IN EQUIPMENT IN CON
Summary of the content on the page No. 9
Upflow Applications Setting Equipment Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum clearances for closet or al- WARNING cove installations are shown in figure 8. Do not install the furnace on its front or its back. Do Upflow Application Installation Clearances not connect the return air ducts to the back of the fur- nace. Doing so will adversely affect the operation of Top the safety control devices, which could result in per- sonal injury or death. T
Summary of the content on the page No. 10
Return Air −− Upflow Applications Single Side Return Air Return air can be brought in through the bottom or either (with transition and filter) 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 furnace and the platform to ensure that the furnace operates properly and safely. The furnace is equipped with a removable bottom 20” X 25” X 1” panel to facilitate installation. (508mm X 63
Summary of the content on the page No. 11
Removing the Bottom Panel Horizontal Applications Remove the two screws that secure the bottom cap to the The ML180UHE furnace can be installed in horizontal ap- furnace. Pivot the bottom cap down to release the bottom plications. Order horizontal suspension kit (51W10) from panel. Once the bottom panel has been removed, reinstall Lennox, or use equivalent suspension method. the bottom cap. See figure 11. Allow for clearances to combustible materials as indicated on the unit nameplate. Minimum c
Summary of the content on the page No. 12
TABLE 1 Horizontal Application Unit Installed on Platform Filter Size Furnace Line contact is permissible but not preferred Cabinet Width Side Return Bottom Return See the unit nameplate for clearances. A − 14−1/2" 16 X 25 X 1 (1) 14 X 25 X 1 (1) B − 17−1/2" 16 X 25 X 1 (1) 16 X 25 X 1 (1) C − 21" 16 X 25 X 1 (1) 20 X 25 X 1 (1) D − 24−1/2" 16 X 25 X 1 (2) 24 X 25 X 1 (1) GAS ENTRY VENT Duct System PIPE Use industry-approved standards (such as those pub- lished by Air Conditioning Contractors of
Summary of the content on the page No. 13
1 − Remove the four mounting screws (figure 15) which Venting secure the combustion air inducer / pressure switch assembly to the orifice plate. Lift the assembly and ro- A 4−inch diameter flue transition is factory-installed on the tate it 90 degrees clockwise or counterclockwise to ei- combustion air inducer outlet of all models. Figure 16 ther the 3 o’clock position or to 9 o’clock position. Re− shows the combustion air inducer as shipped from the secure with four screws. Gasket should be le
Summary of the content on the page No. 14
HORIZONTAL RIGHT POSITION HORIZONTAL LEFT POSITION Top Vent Discharge Top Vent Discharge Vent Pipe Vent Pipe Pressure Switch Pressure Flue Switch Transition Cover Plate AIR AIR Flue Transition FLOW FLOW Collector Box Make−Up Box Cover Plate Collector Box Make−Up Box Disconnect pressure switch hose from barbed fitting on the Gas supply piping must be brought into the unit from the bot- pressure switch assembly. Remove pressure switch assembly tom in order to accommodate the flue pipe. (1
Summary of the content on the page No. 15
The ML180UHE series units are classified as fan−assisted lining system or dedicated gas vent. Unlined masonry chimneys are prohibited. See figures 24 and 25 for com- Category I furnaces when vertically vented according to mon venting. the latest edition of National Fuel Gas Code (NFPA 54 / ANSI Z223.1) in the USA. A fan−assisted Category I fur- A chimney with one or more sides exposed to the outside of the structure is considered to be an exterior chimney. nace is an appliance equipped with an i
Summary of the content on the page No. 16
When inspection reveals that an existing chimney is not Common Venting Using Metal−Lined Masonry Chimney safe for the intended purpose, it shall be rebuilt to conform to nationally recognized standards, lined or relined with SEALED suitable materials, or replaced with a gas vent or chimney suitable for venting ML180UHE series units. The chimney MAX. LENGTH −− SEE NOTE 1 passageway must be checked periodically to ensure that it BELOW. 5 ft. (1.5 m) MIN. LENGTH −− AS is clear and free of obstructi
Summary of the content on the page No. 17
Common Venting Using Tile−Lined Interior Masonry Chimney and Combined Vent Connector MINIMUM LENGTH = AS SHORT AS PRACTICAL. INTERIOR TILE−LINED FOR MAXIMUM LENGTH SEE NOTE TO LEFT MASONRY CHIMNEY NOTE− Refer to provided venting tables for installations. NOTE − the chimney must be properly sized per provided venting tables or lined with listed metal lining system. VENT CONNECTOR OTHER PERMANENTLY APPLIANCE SEALED FIREPLACE OPENING FURNACE FIGURE 25 6 − The entire length of single wall metal ven
Summary of the content on the page No. 18
16 − Vent connectors serving Category I appliances shall two consecutive table size diameters over the size of not be connected to any portion of mechanical draft the draft hood outlet or flue collar outlet. systems operating under positive pressure such as 20 − Do not install a manual damper, barometric draft regu- Category III or IV venting systems. lator or flue restrictor between the furnace and the chimney. 17 − If vent connectors are combined prior to entering the common vent, the maximum
Summary of the content on the page No. 19
TABLE 4 Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors Serving a Single Category I Appliance Vent and Connector Diameter − D (inches) Height Lateral 3 Inch 4 Inch 5 Inch 6 Inch H L Appliance Input Rating in Thousands of Btu Per Hour (feet) (feet) MIN MAX MIN MAX MIN MAX MIN MAX 0 38 77 59 151 85 249 126 373 2 39 51 60 96 85 156 123 231 6 4 NA NA 74 92 102 152 146 225 6 NA NA 83 89 114 147 163 220 0 37 83 58 164 83 273 123 412 2 39 56 59 108 83 176 121 261 8 5 NA NA 77 102
Summary of the content on the page No. 20
TABLE 5 Vent Connector Capacity Type B Double−Wall Vents with Type B Double−Wall Connectors Serving Two or More Category I Appliances Vent and Connector Diameter − D (inches) Vent Connector 3 Inch 4 Inch 5 Inch 6 Inch Height Rise H R Appliance Input Rating in Thousands of Btu Per Hour (feet) (feet) MIN MAX MIN MAX MIN MAX MIN MAX 1 22 37 35 66 46 106 58 164 2 23 41 37 75 48 121 60 183 6 3 24 44 38 81 49 132 62 199 1 22 40 35 72 49 114 64 176 2 23 44 36 80 51 128 66 195 8 3 24 47 37 87 53 139 67
