Lennox International Inc 51M37 51M39 Terminal Designations, Indoor Temperature Measurement Range

Page 34

Technical Specifications

Thermostat Type

Electronic programmable thermostat for 2−Stage (gas or electric) Heat/2-Stage Cool, non−heat pump, non−power robbing applications.

Table 5

51M39 Terminal Designations

Terminal Description

R24VAC

Y1

First-stage cooling

 

 

W1

First-stage heating

 

 

Y2

Second-stage cooling

 

 

W2

Second-stage heating

GFan control

LService Indicator

C24VAC common

TOutdoor temperature sensor connection 1

TOutdoor temperature sensor connection 2

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 18)

 

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 18

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 18).

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, gas or electric heat compatible via DIP switches (also see Thermostat Output section).

I/O Relays

All thermostat relays are latching type to minimize power consumption.

Equipment Protection Timers

Minimum Compressor OFF time: 5 minutes

Minimum Compressor ON time: 4 minutes

Minimum Furnace ON time: 3 minutes

Minimum furnace cycle time (elapsed time between any furnace activation and the next furnace activation): 6 min- utes.

Minimum elapsed time between any compressor activa- tion and the next compressor activation: 6 minutes.

Page 8

505068M 07/05

Page 33 Page 35
Image 34
Page 33 Page 35
Contents 51M37 Merit Series Thermostat Buttons Buttons, Backlight, Timers & SettingsDAY/TIME − Setting the Day and Time Home ScreenHeat − Using the Heat Mode FANCool Mode Disabled Cool − Using the Cool ModeEnabling and Disabling Cool Mode Turn Cool ON/OFFI036 FAN PM I036 FANSettings − Filter/Maintenance Reminders FAN − Controlling the Fan OperationThermostat Reset Settings − Balance PointService Indicator Removing/Installing ThermostatDefault Thermostat Settings Technical SpecificationsOver−Temperature Protection Smart Setback Recovery via DIP switch #6Equipment Protection Timers Maintenance ReminderCooling Demands Thermostat Output TableHeating Demands 51M35 Merit Series 51M35 Merit Series Thermostat505049M 5/1/05 Heat/Cool Mode Disabled Heat − Using the Heat Mode Cool − Using the Cool ModeEnabling and Disabling Heat Mode Turn Heat ON/OFFHold − Using Temperature Hold Modes 1st press Removing and Installing Thermostat I0i451M35 Terminal Designations Gas Heat, Continuous Fan Thermostat OutputsGas Heat, Auto Fan Electric Heat, Auto Fan51M34 Merit Series 51M34 Merit Series Thermostat505048M 5/1/05 51M34 Series 5/2 I036 FAN OFF I0i4 51M34 Terminal Designations Heat Demand Cool Demand No Demand 51M39 Merit Series 51M39 Merit Series ThermostatI026 530 Heat/Cool Mode Disabled Cooling DemandI030 Auto − Using the Autochangeover Mode Copy a Programmed Day to An other Day Filter Maintenance Indicators Displaying Outside TemperatureCheck Outside Temperature Service Indicator FlashingDefault Program Settings Time & Temp Autochangeover Deadband Selection via DIP switch #7 Indoor Temperature Measurement RangeOutdoor Temperature Measurement Range 51M39 Terminal DesignationsThermal-mechanical switch opens W1 and W2 at 93F+/−6F Page 51M42 Merit Series Thermostat 51M42 Merit Series−Day Programmable Thermostat 505069M 07/05 Large Heat Heating Demand FAN Auto MID Reminder Settings Display Using Fan on I026 Default Program Settings − Time & Temp With Electric Backup no outdoor sensorTechnical Specifications 51M42 Terminal Designations 51M38 Merit Series 51M38 Merit Series ThermostatY/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.
Top Page Image Contents