Lennox Merit Series Installation Instructions Manual
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LENNOX MERIT SERIES
TABLE OF CONTENTS
Furnace Specifications ........... 2
™
Gas Furnace ............................ 3
™
Shipping and Packing List........................................... 3
Requirements ............................................................... 3
General ......................................................................... 4
Shipping and Packing List........................................... 4
General ......................................................................... 4
Location/Placement ..................................................... 4
Duct System ................................................................. 5
Installing Optional Cooling Coil ................................... 5
Venting ......................................................................... 6
Gas Piping .................................................................. 17
Electrical .................................................................... 18
INSTALLATION INSTRUCTIONS
E or EC Series ......... 17
™
GAS FURNACE
™
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 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.
CAUTION
!
As with any mechanical equipment, personal
injury can result from contact with sharp
sheet metal edges. Be careful when you
handle this equipment.
Filters ......................................................................... 19
Duct System ............................................................... 19
Venting ....................................................................... 19
Gas Piping .................................................................. 19
Electrical .................................................................... 21
Integrated Control ...................................................... 22
Schematic wiring diagram ... 23
™
Unit Start-Up .............................................................. 24
Gas Pressure Adjustment .......................................... 25
Proper Combustion .................................................... 26
High Altitude .............................................................. 26
Other Unit Adjustments ............................................. 27
Service ....................................................................... 28
Repair Parts ............................................................... 31
506998-01
08/2013 Supersedes 06/2012
1
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Summary of Contents for Lennox Merit Series
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Page 1: Table Of Contents
Gas Pressure Adjustment .......... 25 Installing Optional Cooling Coil ........5 Proper Combustion ............ 26 High Altitude .............. 26 Venting ................. 6 General Lennox Merit Series E or EC Series ..17 Other Unit Adjustments ..........27 ™ Gas Piping ..............17 Service ............... -
Page 2: Lennox Merit Series™ Furnace Specifications
LENNOX MERIT SERIES™ FURNACE SPECIFICATIONS MODEL DIMENSIONS mm ML18007036A-E ML18007036A-EC ML18011060C-E ML18011060C-EC ML18013560D-E ML18013560D-EC NOTE: DUCT CONNECTIONS ARE INTERCHANGEABLE FROM SIDE TO SIDE... -
Page 3: Lennox Merit Series Gas Furnace
1 x Bag assembly containing the following: Unit must be adjusted to obtain a temperature rise within 2 x Screws the range specified on appliance rating plate. This Lennox 1 x Snap bushing Merit Series furnace must be installed so that its electrical ™... -
Page 4: General
˜ Place the furnace as close to the center of the air distribution system as possible. Installation of Lennox outdoor central furnaces must be in accordance with these instructions, local gas fitting ˜ Do not block the furnace combustion air openings with regulations, municipal building codes, electrical wiring clothing, boxes, doors, etc. -
Page 5: Duct System
Refer to the dimensioned drawing on page 2 to locate and 1. Remove Lennox Merit Series Gas Furnace unit rear size the plenum entry into the side of the building. -
Page 6: Venting
VENTING The Lennox Merit Series™ unit is shipped standard for top flue discharge. A flue adapter is supplied with the furnace. It must be installed on the outside of the furnace. FLUE TERMINATION CLEARANCES Figure 1 Minimum clearances mm Ref. Item... - Page 7 VENTING 1 − Remove the four mounting screws ( gure 2) which A 4−inch diameter ue transition is factory-installed on the combustion air inducer outlet of all models. Figure 3 secure the combustion air inducer / pressure switch assembly to the ori ce plate. Lift the assembly and ro- shows the combustion air inducer as shipped from the tate it 90 degrees clockwise or counterclockwise to ei- factory.
- Page 8 VENTING HORIZONTAL LEFT POSITION HORIZONTAL RIGHT POSITION Top Vent Discharge Top Vent Discharge Vent Pipe Vent Pipe Pressure Switch Pressure Flue Switch Transition Cover Plate Flue Transition FLOW Collector Box FLOW Make−Up Box Cover Plate Collector Box Make−Up Box Disconnect pressure switch hose from barbed tting on the Gas supply piping must be brought into the unit from the bot- pressure switch assembly.
- Page 9 VENTING The Lennox Merit Series Gas Furnace units Masonry chimneys used to vent Category I central fur- naces must be either tile-lined or lined with a listed metal are classi ed as fan−assisted Category I furnaces lining system or dedicated gas vent. Unlined masonry when vertically vented according to the latest edition chimneys are prohibited.
- Page 10 VENTING 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 recognised standards, lined or relined with SEALED suitable materials, or replaced with a gas vent or chimney suitable for venting the units.
- Page 11 VENTING 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.
- Page 12 VENTING 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 ue collar outlet. systems operating under positive pressure such as 20 −...
- Page 13 VENTING Capacity of Type B Double−Wall Vents with Single−Wall Metal Connectors Serving a Single Category I Appliance Vent and Connector Diameter − D (mm) Height Lateral 76mm 100mm 125mm 150mm Appliance Input Rating in Thousands of Btu Per Hour NOTE − Single appliance venting con gurations with zero lateral lengths are assumed to have no elbows in the vent system. For all other vent con gurations, the vent system is assumed to have two 90°...
- Page 14 VENTING 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 (mm) Vent Connector 25mm 50mm 125mm 150mm Height Rise Appliance Input Rating in Thousands of Btu Per Hour Common Vent Capacity Type B Double−Wall Vents with Type B Double−Wall Connectors Serving Two or More Category I Appliances...
- Page 15 VENTING Vent Connector Capacity Type B Double−Wall Vents with Single−Wall Metal Connectors Serving Two or More Category I Appliances Vent and Connector Diameter − D (mm) Height Lateral 76mm 100mm 125mm 150mm Appliance Input Rating in Thousands of Btu Per Hour NOTE −...
- Page 16 VENTING Removal of the Furnace from Common Vent 3 − Close all building doors and windows and all doors be- tween the space in which the appliances remaining In the event that an existing furnace is removed from a connected to the common venting system are located venting system commonly run with separate gas ap- and other spaces of the building.
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Page 17: General Lennox Merit Series ™ E Or Ec Series
3. Gas piping must not run in or through air ducts, clothes GENERAL E OR EC SERIES chutes, chimneys or gas vents, dumb waiters or elevator shafts. THERMOSTAT INSTALLATION 4. Piping should be sloped 6mm per 380mm upward toward Install a room thermostat according to the instructions the meter from the furnace. -
Page 18: Electrical
4. Install a separate disconnect switch (protected by either IMPORTANT fuse or circuit breaker) near the unit so power can be turned off for servicing. When testing pressure of gas lines, gas valve 5. Before connecting thermostat or power wiring, check must be disconnected and isolated. -
Page 19: Filters
VENTING 6. In some localities, codes may require the installation of a manual main shut off valve and union (furnished by the The Lennox Merit Series Gas Furnace is a fan-assisted ™ installer) external to the unit. The union must be of the furnace equipped with an integral mechanical means to ground joint type. - Page 20 IMPORTANT Compounds used on threaded joints of gas piping must be resistant to the actions of liquified petroleum gases. NOTE: If emergency shut-off is necessary, shut off the main manual gas valve and disconnect main power to the furnace. The installer should properly label these devices. Figure 14 Left Side Piping MANUAL...
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Page 21: Electrical
CAUTION control. Some soaps used for leak detection are A power wiring harness is shipped with each Lennox Merit corrosive to certain metals. Carefully rinse Series furnace. An IEC receptacle is provided on the right ™... -
Page 22: Integrated Control
˜ Generator should have a wave form distortion of less than there is no cooling or heating demand. 5% THD (total harmonic distortion) 2. When the Lennox Merit Series is running in the heating ™ mode, the indoor blower will run on the heating speed. -
Page 23: Lennox Merit Series ™ Schematic Wiring Diagram
SCHEMATIC WIRING DIAGRAM LENNOX MERIT SERIES GAS FURNACE ™ Figure 18... -
Page 24: Unit Start-Up
PORT heavier than air and will settle on the floor. The gas valve on GAS VALVE SHOWN IN OFF POSITION the Lennox Merit Series unit will be equipped with a gas ™ control switch. Use only your hand to move the switch. Never use tools. -
Page 25: Gas Pressure Adjustment
TURNING OFF GAS TO UNIT 6. If flame is not detected after first ignition trial, the ignition control will repeat steps 3 and 4 four more 1. Set the thermostat to the lowest setting. times before locking out the gas valve (“WATCHGUARD” 2. -
Page 26: Proper Combustion
PROPER COMBUSTION HIGH ALTITUDE Furnace should operate a minimum 15 minutes with correct The manifold pressure may require adjustment and manifold pressure and gas flow rate before checking combustion air pressure switch may need replacing to combustion. Take combustion sample beyond the flue outlet ensure proper combustion at higher altitudes. -
Page 27: Other Unit Adjustments
Table 5 Pressure Switch and Gas Conversion kits at all Altitudes High Altitude Natural Gas to LP/ LP/Propane to High Altitude Natural Gas Propane Gas Change Natural Gas Burner Orifice Pressure Switch kit over kit Change over kit Model Input 1525- 0-1524m Size... -
Page 28: Service
ELECTRICAL SERVICE 1. Check all wiring for loose connections. 2. Check for the correct voltage at the furnace (furnace WARNING operating). Correct voltage is 230VAC + 10%. 3. Check amp-draw on the blower motor with inner blower panel in place. ELECTRICAL SHOCk, FIRE, OR EXPLOSION HAZARD. - Page 29 5. Reinstall burner box, manifold assembly and burner box cover. 6. Re-install gas supply and turn on electrical power to furnace. Figure 21 LENNOX MERIT SERIES™ BURNER ASSEMBLY & REMOVAL ML180UHA BURNER ASSEMBLY & REMOVAL Retention Rings Ignitor Rollout Switches...
- Page 30 COILING FITTING INSTRUCTIONS COIL FITTING INSTRUCTIONS Figure 22 Figure 23 Page 19 of 26...
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Page 31: Repair Parts
DOOR INTERLOCK SWITCH REPAIR PARTS LIST The following repair parts are available through independent Lennox dealers. When ordering parts, include the complete furnace model number listed on the CSA International nameplate - Example: ML18007036A-E. All service must be performed by a licensed professional installer (or equivalent), service agency, or gas supplier. - Page 32 LENNOX MERIT SERIES™ EXTERNAL PARTS ARRANGEMENT Figure 25 Figure 26 LENNOX MERIT SERIES™ EXTERNAL WITH COIL PARTS ARRANGEMENT...
- Page 33 Australia 13 23 50 New Zealand 0800 653 330 Web www.lennoxaus.com.au...