Lennox Merit Series Gas Furnace - Manual

Lennox Merit Series Gas Furnace

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Table of Contents:

  • Page 2 – SUPPLY AIR; FRONT VIEW
  • Page 3 – Parts Arrangement; FIGURE 1
  • Page 4 – Shipping and Packing List; Package 1 of 1 contains; Safety Information; DANGER; WARNING; Certifications
  • Page 5 – Heating Unit Installed Upstream of Cooling Unit; Gas Unit; Use of Furnace as Construction Heater
  • Page 6 – Product contains fiberglass wool.; CAUTION
  • Page 7 – FIGURE 3
  • Page 8 – FIGURE 4
  • Page 9 – Setting Equipment; The unit must be level.; Upflow Applications; Upflow Application Installation Clearances; FIGURE 8
  • Page 10 – − Single side return air with transition to accommodate 20; Refer to Engineering Handbook for additional information.; Transition; Single Side Return Air; SIDE VIEW; SIDE RETURN
  • Page 11 – Horizontal Applications; NOTE −
  • Page 12 – Filters; TABLE 1; Duct System
  • Page 13 – Venting; Mounting Screws Location; Upflow Position; Top Vent Discharge; IMPORTANT; − Remove the four mounting screws (figure 15) which; Left Side Vent Discharge; UPFLOW POSITION; Right Side Vent Discharge
  • Page 14 – HORIZONTAL LEFT POSITION; Side Vent Discharge; HORIZONTAL RIGHT POSITION
  • Page 15 – VENT CONNECTION UPFLOW AND HORIZONTAL POSITION
  • Page 16 – Common Venting Using Metal−Lined Masonry Chimney; General Venting Requirements
  • Page 17 – TABLE 2; Connector Diameter
  • Page 23 – Gas Piping; Gas Supply; NOTE − Capacity given in cubic feet (m
  • Page 24 – Horizontal Application
  • Page 25 – Leak Check; Electrical; Precautions and Procedures
  • Page 26 – Indoor Blower Speeds
  • Page 27 – ML180UH Schematic Wiring Diagram and Sequence of Operation
  • Page 28 – TYPICAL ML180UH FIELD WIRING DIAGRAM; INTEGRATED CONTROL
  • Page 29 – Unit Start−Up
  • Page 30 – Gas Pressure Adjustment; NOTE; Proper Combustion; High Altitude
  • Page 31 – Other Unit Adjustments; After the furnace has been started, and supply and return
  • Page 33 – BLOWER DATA
  • Page 35 – Service; Blower
  • Page 39 – Integrated Control Diagnostic Codes; DIAGNOSTIC CODES; DESCRIPTION
  • Page 40 – Troubleshooting: Heating Sequence of Operation; HEATING SEQUENCE OF OPERATION; NORMAL HEATING MODE; (Flame sensed without gas valve energized)
  • Page 41 – HEATING SEQUENCE CONTINUED
  • Page 42 – Troubleshooting: Cooling Sequence of Operation; COOLING SEQUENCE OF OPERATION; NORMAL COOLING MODE
  • Page 43 – Troubleshooting: Continuous Fan Sequence of Operation; CONTINUOUS HEAT SPEED FAN SEQUENCE OF OPERATION
Loading the manual

Page 1

06/11

*2P0611*

506816−01

*P506816-01*

2011 Lennox Industries Inc.

Dallas, Texas, USA

AIR FLOW

UPFLOW

AIR FLOW

AIR FLOW

HORIZONTAL RIGHT

HORIZONTAL LEFT

INSTALLATION
INSTRUCTIONS

ML180UH

MERIT

®

SERIES GAS FURNACE

UPFLOW / HORIZONTAL AIR DISCHARGE

506816−01
06/2011
Supersedes 506778−01

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, person-
al 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.

Table of Contents

Unit Dimensions

2

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Parts Arrangement

3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ML180UH Gas Furnace

4

. . . . . . . . . . . . . . . . . . . . . . . . . .

Shipping and Packing List

4

. . . . . . . . . . . . . . . . . . . . . . . .

Safety Information

4

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Use of Furnace as a Construction Heater

5

. . . . . . . . . . .

General

5

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Combustion, Dilution & Ventilation Air

6

. . . . . . . . . . . . . .

Setting Equipment

9

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Filters

12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Duct System

12

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Venting

13

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Piping

23

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Electrical

25

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Integrated Control

28

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Unit Start−Up

29

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Gas Pressure Adjustment

30

. . . . . . . . . . . . . . . . . . . . . . .

High Altitude

30

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Proper Combustion

30

. . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Other Unit Adjustments

31

. . . . . . . . . . . . . . . . . . . . . . . . . .

Blower Performance Data

33

. . . . . . . . . . . . . . . . . . . . . . .

Service

35

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Planned Service

38

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Repair Parts List

38

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Integrated Control Diagnostic Codes

39

. . . . . . . . . . . . . .

Troubleshooting

40

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Summary

Page 2 - SUPPLY AIR; FRONT VIEW

Page 2 Unit Dimensions − inches (mm) 2 Flue outlet may be horizontal but furnace must be vented vertically 3 Optional external side return air filter kit cannot be used with the optional RAB Return Air Base. 1 NOTE − 60C and 60D units that require air volumes over 1800 cfm (850 L/s) must have one of...

Page 3 - Parts Arrangement; FIGURE 1

Page 3 Parts Arrangement FIGURE 1 Secondary Limits Blower Assembly Control Box (includes integrated control, interlock switch and transformer) Gas Valve Burner Box (includes sensor, ignitor and rollout switches) Combustion Air Inducer Combustion Air Inducer Pressure Switch Heat Exchanger Upper Acces...

Page 4 - Shipping and Packing List; Package 1 of 1 contains; Safety Information; DANGER; WARNING; Certifications

Page 4 ML180UH Gas Furnace The ML180UH unit is shipped ready for installation in theupflow or horizontal right position (for horizontal left posi-tion the combustion air pressure switch must be moved).The furnace is shipped with the bottom panel in place. Thebottom panel must be removed if the unit ...

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