Lennox International Inc Comprehensive Guide to the 51M37 Thermostat's Technical Specifications
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Technical Specifications

Thermostat Type

Electronic programmable thermostat for heat pump, 3-stage heat/2-stage cool.

NOTE − 2 stages of heat pump heat and one stage of auxil- iary (gas or electric) backup heat are supported.

Power Supply Range

18VAC − 30VAC (24VAC nominal), 60Hz

CAUTION

24VAC is present on the terminals of the thermostat bracket. If removing the thermostat from the wall, use caution and avoid touching any of the connec- tor terminals on the wall bracket.

Also, when working with the thermostat dip switches, use a non−conductive tool and take cau- tion to avoid making any contact with the circuit board, its imprinted circuitry and its connector prongs.

Temperature Display

Display Scale: Fahrenheit or Celsius user selectable (via DIP switch; see figure 21)

Display range: 35°F (2°C) to 99°F (37°C)

Display resolution: 1°F (1°C)

Display Accuracy: +/−1°F

If the Fahrenheit/Celsius display must be changed, use a plastic, non−conductive tool to push the dip switch to the right position (see figure 21).

 

Changing Fahrenheit/Celsius Setting

1

 

2

 

3

 

4

 

5

 

6

PLUG IN (Use Care To Avoid Bending Prongs.)

7

 

 

F/C (Fahrenheit/Celsius) switch

 

shown in Celsius position

Figure 21

Indoor Temperature Measurement Range

Measurement Scale: Fahrenheit

Measurement Range: 35°F to 99°F

Measurement Resolution: 0.5°F

Measurement Accuracy: +/−1°F

Field Offset: via DIP switches to +/−3°F

Sampling Method: temperature measurements sampled every 15 seconds. Displayed temperature is the average of the last four measurements.

Outdoor Temperature Measurement Range

Measurement Scale: Fahrenheit

Measurement Range: −22°F to 122°F

Measurement Resolution: 1°F

Measurement Accuracy: +/−2°F

Temperature Setpoint Range

Setting range: 50°F (10°C) to 90°F (32°C)

Setting resolution: 1°F (1°C)

Smart Setback Recovery (via DIP switch #6)

Smart Setback Recovery (SSR) affects the way the ther- mostat responds to program events. If SSR is disabled, the thermostat will react to a program event at the time the event occurs. However, if SSR is enabled, the thermostat will react to a program event before the event occurs such that the desired temperature is reached at the time of the event, not after.

Autochangeover Deadband Selection (via DIP switch #7)

Autochangeover deadband can be set to 4 or 6 degrees. When autochangeover is enabled (via the AUTO button), the thermostat will automatically change over from heating to cooling and vice versa, to keep the room temperature in between the heating and cooling setpoints. The deadband is the minimum difference between the heating and cooling setpoints.

Fan Control

AUTO or ON modes.

I/O Relays

All thermostat relays are latching type to minimize power consumption.

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51M42 SERIES 5/2

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Contents 51M37 Merit Series DAY/TIME − Setting the Day and Time Buttons, Backlight, Timers & SettingsThermostat Buttons Home ScreenFAN Heat − Using the Heat ModeEnabling and Disabling Cool Mode Cool − Using the Cool ModeCool Mode Disabled Turn Cool ON/OFFPM I036 FAN I036 FANFAN − Controlling the Fan Operation Settings − Filter/Maintenance RemindersService Indicator Settings − Balance PointThermostat Reset Removing/Installing ThermostatTechnical Specifications Default Thermostat SettingsEquipment Protection Timers Smart Setback Recovery via DIP switch #6Over−Temperature Protection Maintenance ReminderThermostat Output Table Cooling DemandsHeating Demands 51M35 Merit Series Thermostat 51M35 Merit Series505049M 5/1/05 Enabling and Disabling Heat Mode Heat − Using the Heat Mode Cool − Using the Cool ModeHeat/Cool Mode Disabled Turn Heat ON/OFFHold − Using Temperature Hold Modes 1st press I0i4 Removing and Installing Thermostat51M35 Terminal Designations Gas Heat, Auto Fan Thermostat OutputsGas Heat, Continuous Fan Electric Heat, Auto Fan51M34 Merit Series Thermostat 51M34 Merit Series505048M 5/1/05 51M34 Series 5/2 I036 FAN OFF I0i4 51M34 Terminal Designations Heat Demand Cool Demand No Demand 51M39 Merit Series Thermostat 51M39 Merit SeriesI026 Heat/Cool Mode Disabled Cooling Demand 530I030 Auto − Using the Autochangeover Mode Copy a Programmed Day to An other Day Check Outside Temperature Displaying Outside TemperatureFilter Maintenance Indicators Service Indicator FlashingDefault Program Settings Time & Temp Outdoor Temperature Measurement Range Indoor Temperature Measurement RangeAutochangeover Deadband Selection via DIP switch #7 51M39 Terminal DesignationsThermal-mechanical switch opens W1 and W2 at 93F+/−6F Page 51M42 Merit Series 51M42 Merit Series Thermostat−Day Programmable Thermostat 505069M 07/05 Large Heat Heating Demand FAN Auto MID Reminder Settings Display Using Fan on I026 With Electric Backup no outdoor sensor Default Program Settings − Time & TempTechnical Specifications 51M42 Terminal Designations 51M38 Merit Series Thermostat 51M38 Merit SeriesY/TIME button 51M38 Series 5/2 Hold − Using Temperature Hold Modes Repeat steps a and B for as many days as you Settings Thermostat Output Table 51M38 Terminal Designations

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.
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