E2005 Lennox Industries Inc.

Dallas, Texas, USA

RETAIN THESE INSTRUCTIONS

FOR FUTURE REFERENCE

51M38 Merit® Series Thermostat

The Lennox Merit® Series 7 day programmable electronic thermostat 51M38 provides excellent temperature control and a large, easy-to-read display. This product includes a programmable filter change reminder, an equipment maintenance reminder, and a system check indicator to notify the user when the equipment requires service.

Thermostat 51M38 is suitable for non−heat pump, single- stage heat/single-stage cool applications with either gas or electric furnace. Also, the thermostat provides auto- changeover capability.

OPERATION

MANUAL

51M38 Merit® Series

7 Day Programmable Thermostat

CONTROLS

505,067M

 

 

Litho U.S.A.

07/05

 

 

Table of Contents

51M38 Series Thermostat . . . . . . . . . . . . . . . . . . . . . . 1

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Initial Thermostat Power-up . . . . . . . . . . . . . . . . . . . . . 1

Buttons, Backlight, Timers & Settings . . . . . . . . . . . . 2

DAY/TIME − Set Day and Time . . . . . . . . . . . . . . . . . . 2

HEAT − Heat Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

COOL − Cool Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

AUTO − Using the Autochangeover Mode . . . . . . . . . 3

HOLD − Temperature Hold Mode . . . . . . . . . . . . . . . . 4

PROG − Thermostat Programming . . . . . . . . . . . . . . . 4

COPY − Copy a Program . . . . . . . . . . . . . . . . . . . . . . . 5

FAN − Controlling Fan Operation . . . . . . . . . . . . . . . . . 5

Displaying Outside Temperature . . . . . . . . . . . . . . . . . 5

SETTINGS − Filter /Maintenance Reminder . . . . . . . 5

Service Indicator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Thermostat RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Removing/Installing Thermostat . . . . . . . . . . . . . . . . . 6

Default Thermostat Settings . . . . . . . . . . . . . . . . . . . . 6

Thermostat Output Table . . . . . . . . . . . . . . . . . . . . . . . 7

Technical Specifications . . . . . . . . . . . . . . . . . . . . . . . . 7

General

These instructions are intended as a general guide and do not supersede local codes in any way. Consult authorities having jurisdiction before installation.

Check equipment for shipping damage. If you find any damage, immediately contact the last carrier.

Introduction

This document describes the operation of Lennox thermo- stat 51M38. Refer to the installation manual for instructions regarding installation and wiring of the thermostat.

Initial Thermostat Power-up

When power is initially applied to the thermostat, the dis- play will appear as shown in figure 1.

Initial Power−Up Display

Copy tofrom MO TU WE TH FR SA SU

PROG

AM

 

 

A B C D

 

 

HOLD

PM I8:88

FAN ON

COOL SETPOINT

 

AUTO

 

 

°

 

FILTER SERVICE

 

COOL

MAINTENANCE

 

 

 

OFF

 

 

 

OUTROOM

 

AUTO

HEAT SETPOINT

EMG.

 

°

 

°

HEAT

i88

 

Hi

 

Lo

Figure 1

All display segments are momentarily activated. This oc- curs as a normal part of thermostat initialization.

07/05

Page 1

505,067M

*2P0705*

*P505067M*

 

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Lennox International Inc 51M37 operation manual 51M38 Merit Series Thermostat

51M37 specifications

Lennox International Inc, a prominent player in the heating, ventilation, and air conditioning (HVAC) market, has made significant strides in innovation and technology in recent years. Among its notable offerings is the Lennox 51M37, a well-engineered component designed to enhance HVAC efficiency and reliability.

The 51M37 is primarily known for its advanced motor technology, incorporating ECM (Electronically Commutated Motor) design, which significantly reduces energy consumption compared to traditional motor systems. This motor type is key to Lennox's commitment to sustainability, as it not only maintains optimal performance but also minimizes the carbon footprint associated with residential and commercial heating and cooling tasks.

A standout feature of the 51M37 is its intelligent control system, which allows for more precise management of airflow and temperature. This technology can adapt to specific environmental conditions and consumption patterns, optimizing performance and providing substantial cost savings on energy bills. The integration of smart technology aligns with modern demands for energy efficiency and control, making the 51M37 a vital component in achieving higher energy ratings for HVAC systems.

In terms of compatibility, the 51M37 is engineered to work seamlessly with a variety of Lennox heating and cooling units, ensuring versatility for both new installations and retrofits. This compatibility enhances system integration, resulting in improved overall performance.

The construction of the 51M37 emphasizes durability and reliability, featuring high-quality materials that withstand the challenges of constant operation. Its robust design is perfect for diverse environments, ensuring that it functions reliably in both residential settings and commercial applications.

Another characteristic worth noting is the user-friendly installation process, allowing HVAC technicians to install the 51M37 with relative ease. This not only reduces labor costs but also ensures that the system can commence operation quickly without extensive downtime.

Overall, Lennox International's 51M37 embodies innovation, efficiency, and reliability in HVAC technology. With its advanced ECM motor, intelligent controls, and durable construction, it stands as a prime example of how modern HVAC solutions can lead to enhanced performance and energy savings. As the industry continues to evolve, products like the 51M37 will play a critical role in shaping the future of heating and cooling, aligning with sustainability goals and meeting the needs of consumers.