Lennox 49M55 Deluxe Programmable Thermostat
IMPORTANT SAFETY INFORMATION
WARNING:
- Always turn off power at the main power source by unscrewing fuse or switching circuit breaker to the off position before installing, removing, or cleaning this thermostat.
- Read all of the information in this manual before programming this thermostat.
- This is a 24V AC low-voltage thermostat. Do not install on voltages higher than 30V AC.
- All wiring must conform to local and national building and electrical codes and ordinances.
- Do not short (jumper) across terminals on the gas valve or at the system control to test installation. This will damage the thermostat and void the warranty.
- This thermostat is equipped with automatic compressor protection to prevent potential damage due to short cycling or extended power outages. The short cycle protection provides a 5-minute delay between heating or cooling cycles to prevent the compressor from being damaged.
- Do not switch system to cool if the temperature is below 45°F (7°C). This can damage the cooling system and may cause personal injury.
- Use this thermostat only as described in this manual.
How do I change the time of day and day of the week?
How do I turn on the heating or cooling cycles?
How do I cycle the fan?
How do I cycle the fan?
INTERMITTENT will turn the fan on for a set period of time for a given interval.
The thermostat will cycle the fan on for the set ON cycle. The fan will remain off for the set OFF cycle.
If the HVAC system runs for a longer period than the ON cycle, the OFF cycle will start counting over again when the system shuts off.
How do I temporarily change the temperature?
Can I set a temporary adjustment for longer than 3 hours?
Can I set the thermostat to hold one temperature indefinitely?
How do I return to the Program Mode after being in HOLD?
Simply press the RESUME PROGRAM button. This works from all HOLD screens 
How do I set the Vacation Mode?
How do I program my thermostat? 
How do I copy one day’s program to another day?
What is an event?
An event is a programming period. This could be the period in the morning when you are preparing for work or school. It could be the period when no one is at home. It could be the period when the household is asleep at night.
The time for an event is selected based on when you want the event to occur. For example, if you wake up at 6:30 AM, set the first event for 6:30 AM. The thermostat will automatically make sure that your home is at the desire temperature selected for that event by the time you wake.
This thermostat can be selected for 2, 4, or 6 events. Two events should be selected if someone is home all day thereby requiring a constant temperature during the day and a different temperature at night.
Four events are the most common for working households. Event 1 (WAKE) is the morning period. Event 2 (DAY) is when everybody has left for school or work. Event 3 (EVE) is the return period, coming home from school or work. Event 4 (NIGHT) is the night period when everybody is asleep.
Six events can be used especially when there is activity during the day. Event 1 (WAKE) is the morning period. Event 2 (MORN) is when everybody has left for school or work. Event 3 (NOON) is the lunch period, when the kids may be home for a break. Event 4 (DAY) is the afternoon period when the house is empty. Event 5 (EVE) is the return period, coming home from school or work. Event 6 (NIGHT) is the night period when everybody is asleep.
How do I know what program is right for me?
The thermostat is set up with the US EPA ENERGYSTAR® recommended times and temperatures for optimal energy savings. You can change these to suit your lifestyle.
The best rule is to examine your schedule and set the times and temperatures that best fit. This thermostat is so versatile, you can easily temporarily change temperatures or programs at a whim.
What are the USER settings?
- The USER SETTINGS can change the way information is displayed on the thermostat and help to optimize comfort. Its one way to truly personalize your new thermostat.
- To get to the USER SETTINGS, press the MENU button from the main screen.
USER SETTINGS are below the FAN settings. Use the DOWN button to scroll below the screen. Press SELECT. - Choose the setting you would like to change. When the SETTING is highlighted, press SELECT. There are 13 USER
SETTINGS in all as listed below. For detailed information on each user setting, please go to the next page.
Detailed Information on the USER SETTINGS (Or what do these USER SETTINGS do?)
To select a USER SETTING, use the UP or DOWN button to highlight the desired value. Press SELECT to select the desired value.
- TEMPERATURE: Fahrenheit or Celsius
The temperature will be displayed in F or C.
- CLOCK SETTINGS
Displays time in standard 12-hour format or military format. - SETPOINT TEMPERATURE
Each event has a set point temperature. Choose whether to display this value or not.
- NUMBER OF EVENTS PER DAY
Select events per day. Choose from 2, 4, or 6 events per day.
More Detailed Information on the USER SETTINGS
DIFFERENTIAL SETTINGS
The temperature differential is your comfort level. A lower differential means your system may cycle with greater frequency but will control closer to desired setpoint temperature.The second stage delay is a timed delay to indicate how much time should pass before the second stage is turned on. This is an energy-saving feature. To use less energy, set this higher. For greater comfort, set it lower.
HEATING and COOLING LIMITS
To prevent individuals (probably your kids) from adjusting the thermostat too hot or too cold, you can limit the maximum setting for the heating and cooling modes. This will help you save on energy costs.
LANGUAGE SETTING
This screen allows you to choose the displayed language; English, French, or Spanish.
SECURITY SETTINGS
In order to prevent tampering with the program and your desired settings, two levels of security are available. The first will allow only temporary changes to the temperature. It protects all other programmed setpoints. The second will restrict changes to EVERYTHING, including temporary changes to the temperature.
SECURITY CODE
On this screen, you enter a four-digit code. Use the UP or DOWN button to change the first value, and press SELECT. The second digit will be highlighted. Repeat for all four values. And dont forget your code. If you do, you will have to reset the entire thermostat and that will erase all the schedules you’ve programmed into the unit.
When would I need to change the USER settings?
The only features you may need to change are the temperature differentials (if you desire additional comfort) and the security settings. All the other settings probably will not need to be changed.
What are the INSTALLER settings?
The INSTALLER SETTINGS are setup during the initial installation. They tell the thermostat how to function with your heating or cooling equipment. The following is a brief overview and discussion of these settings.
- SYSTEM SETUP
Choose the system component which the thermostat will control.
- 1st STAGE HEATING
The 49M55 and the 49M56 can have gas/oil or electric first-stage heating.
Choose the energy source for 1st stage heating. - AUXILIARY HEAT
The 49M57 can be set to use your 2H/2C heat pump internal auxiliary heating or to use an external add-on source. The add-on feature will be used most often when a single stage heat pump uses a gas or electric furnace as its second stage of heating.
- RESIDUAL COOL
In order to get greater efficiency from the cooling system, the fan can be programmed to run for 0 (OFF), 30, 60, 90, or 120 seconds after the air conditioner has shut off. Residual cool may interfere with proper system operation. Refer to the system operating manual. - BALANCE POINTS
This screen will appear only when the optional outdoor sensor (46M98) is connected to the thermostat. When this sensor is used with the 49M57, you can set the lower and upper temperatures to disable or enable 2nd stage heat.
- AUTO CHANGEOVER
When turned on, the thermostat will switch automatically between heating and cooling to maintain the optimal temperature in your home. - ENERGY-EFFICIENT RECOVERY
When turned on, the thermostat will look up to two hours before the next event and anticipate when to turn on to reach the desired temperature.
- DEADBAND SETPOINT
Deadband is used with the AUTO CHANGEOVER feature. The deadband is the temperature difference from the setpoint temperature during which the heating or cooling will not be turned on.
This is adjustable from 2-8°F (1.0-4°C). - SECURITY CODE
Enter a code to prevent changes to the INSTALLER settings.
- CONTACT INFORMATION
This allows the servicing HVAC contractor to put their name and phone number into the thermostat to remind you when service may be required.
- SERVICE MONITOR MENU
Two menus are available, the Service Monitor and the Filter Monitor. Both can be set for either the HVAC system run time or based on the calendar. See Reminder Interval. The Service Monitor can be set from OFF to 360 Days in 30 day increments or OFF to 980 in 20-hour increments.
The Filter Monitor can be set from OFF to 360 Days in 30-day increments or OFF to 980 in 20-hour increments. - REMINDER INTERVAL
The Reminder Interval can be set for either HVAC System run time or based on the calendar.
If Run Time is chosen, the service reminder will be set in hours. After the HVAC system has been operating for the selected number of hours, a Service Reminder will be displayed informing you that service is suggested for your system.
If Calendar Time is chosen, the service reminders will be set in days. After the selected number of days has passed, a Service Reminder will be displayed informing you that service is suggested for your system.
When would I need to change the INSTALLER settings?
NEVER! The INSTALLER SETTINGS are selected based on the type of equipment you have in your home. This feature should be set only by a certified HVAC technician. Changing these settings could result in higher energy costs and may even damage your equipment. There is a security lock on this feature to prevent tampering. USE IT!
How does Energy Efficient Recovery (EER) work?
Energy Efficient Recovery is an energy-saving feature. During a setback period (or set up in cooling), it allows the thermostat to look up to two hours ahead to determine when to turn on the heating (cooling) system. During this time period, the second stage is locked out to allow the first (and most efficient stage) to bring your home to the desired temperature.
How does my remote outdoor sensor work?
The remote outdoor sensor (part # 46M98) can be used to aid in the comfort of your home or simply as a sensing device to inquire about outdoor conditions. In most applications, the thermostat will have a display of the temperature sensed by the remote outdoor sensor. With your heat pump system, the remote outdoor sensor can help determine when to turn on the second stage of heating for optimal comfort.
Where should I install a remote outdoor sensor?
The remote outdoor sensor should be installed on the northern wall of your home, away from direct sunlight or other heat sources that may affect its sensitivity.
Who should I call for additional help?
For additional troubleshooting information, visit our website at www.lennox.com. To talk with a service representative, give us a call at 800-9LENNOX.
What should I do if my power goes out?
Make sure your family is safe and don’t worry about the thermostat. Your thermostat automatically retains the time of day for approximately two hours in the event of a power outage. All other programmed parameters are stored permanently in memory. So, if your power is out for more than two hours, simply reset the clock. See page 5.
How do I reset the thermostat program to factory conditions?
To reset the thermostat to factory conditions, press the UP button and the LEFT button at the same time. Hold for 3 seconds. The time of day will display 12:00 indicating a reset has occurred.
NOTE: This will erase all programming and return the thermostat to the factory conditions including the installer settings. Use this only as a last resort.
How do I know if the heating or cooling is on?
The display of the thermostat will indicate the operating mode, HEAT or COOL. When the temperature in your home decreases or increases, the HEATING or COOLING cycle will come on based on the displayed mode. When the HVAC system is ON, LEDs along the bottom crease will turn on.
My energy bills are too high. Is there anything I can do?
While we can’t do anything about the high cost of energy, we can try to use less energy thereby lowering our heating and cooling costs.
Generally, the best way to do this is to use the EPA ENERGYSTAR® recommended setpoints for heating and cooling.
| ENERGYSTAR® Setpoints | ||
| Winter | Summer | |
| (Heating) | (Cooling) | |
| Morning | 70°F (21°C) | 78°F (25°C) |
| Day | 62°F (17°C) | 85°F (29°C) |
| Evening | 70°F (21°C) | 78°F (25°C) |
| Night | 62°F (17°C) | 82°F (28°C) |
Another way to contain costs is to cycle the heat pump or air conditioner in moderation. The thermostat controls the cycle rate based on temperature differentials. By maintaining a reasonable differential setpoint, 1°F for 1st stage and 2°F for 2nd stage, your furnace will cycle with moderation.
Finally, using the remote outdoor sensor coupled with the balance point feature (see INSTALLER SETTINGS, page 19) will allow your furnace to cycle to the most efficient stage for your heating or cooling needs.
References:
Download Manual
Lennox 49M55 Deluxe Programmable Thermostat User Manual
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