The Honeywell RTH221B is a user-friendly, 1-week programmable thermostat designed for compatibility with various heating and cooling systems. It offers intuitive controls, programmable scheduling, and energy-saving features like built-in compressor protection, ensuring efficient temperature management. Battery-operated with a clear display, it’s an ideal solution for homeowners seeking reliable climate control.
1.1 Key Features and Benefits
The Honeywell RTH221B thermostat offers a range of features designed for convenience and energy efficiency. Its programmable scheduling allows users to set up to four periods per day, optimizing comfort and energy savings. The thermostat is compatible with gas, oil, electric, and hot water systems, making it versatile for various home setups. It includes built-in compressor protection to prevent damage to cooling systems and a backlit display for easy readability. Battery operation eliminates the need for hardwiring, while the simple interface ensures intuitive control. These features make the RTH221B a practical and reliable choice for homeowners.
1.2 Compatibility with Various Heating and Cooling Systems
The Honeywell RTH221B thermostat is compatible with a wide range of heating and cooling systems, including gas, oil, and electric furnaces, as well as central air conditioning and hot water systems. It can also be used with millivolt systems, making it a versatile option for different household setups. However, it is not suitable for heat pumps with backup heat or multistage systems. This broad compatibility ensures that the RTH221B can be effectively integrated into various home environments, providing reliable temperature control without requiring extensive system modifications.
Installation Guide
Install batteries, set the fan operation switch, and ensure compatibility with your system. Follow the manual for proper setup, ensuring the thermostat works efficiently with your heating/cooling setup.
2.1 Identifying System Type
To ensure proper installation, identify your system type. The Honeywell RTH221B is compatible with gas, oil, or electric furnaces, central air conditioners, hot water systems, and millivolt systems. It is not suitable for heat pumps with backup heat or multistage systems. Refer to the manual for detailed system identification guidance. Match your system type to the thermostat’s compatibility to ensure correct setup and operation. This step is crucial for optimal performance and to avoid potential damage to your HVAC system.
2.2 Installing Batteries
Install two fresh AAA batteries in the thermostat to power it. When the “Lo Batt” indicator appears, replace the batteries within 60 days. Ensure the system switch is set to “Off” before removing the batteries to prevent the heating/cooling system from activating. Replace batteries annually or when away for an extended period. After replacement, the clock and day settings must be reset, as other settings are stored in non-volatile memory. Proper battery installation ensures reliable operation and maintains your programmed settings.
2.3 Setting the Fan Operation Switch
The fan operation switch on the Honeywell RTH221B thermostat controls the fan’s operation during heating and cooling cycles. For gas or oil systems, leave the switch in the default position to allow the system to control the fan. For electric or heat pump systems, switch to the alternate position to enable thermostat-controlled fan operation. This setting ensures the fan operates efficiently, reducing energy usage and improving comfort. Proper configuration is essential for optimal system performance and to avoid unnecessary wear on the HVAC system components.
2.4 Advanced Installation Considerations
For advanced setups, ensure the Honeywell RTH221B is compatible with your system type, such as heat pumps or high-efficiency furnaces. If installing on a heat pump without auxiliary heat, connect the O or B terminal, not both. For systems requiring a jumper wire, place it between Y and W terminals. Avoid using the C or X terminals, and wrap any bare wire ends with electrical tape to prevent short circuits. Always test the system after installation to ensure proper operation. If unsure, refer to the manual or contact Honeywell support for assistance. Correct installation is crucial to avoid equipment damage and ensure optimal performance.
Thermostat Features
The Honeywell RTH221B features a backlit display, easy-to-use buttons, and a fan/system switch. It offers compressor protection, temporary/permanent overrides, and compatibility with various HVAC systems. Battery-operated with adaptive controls.
3.1 Display Screen Overview
The RTH221B’s display screen is a clear LCD that shows the current temperature, setpoint, and system status. It also indicates the day and time, ensuring easy monitoring. The screen displays messages like “Lo Batt” for low battery warnings and “Cool On” or “Heat On” during compressor protection. The interface is user-friendly, with intuitive indicators for fan operation and system mode (Heat/Cool). The display is backlit, allowing easy visibility in low-light conditions, and flashes during overrides or errors to alert users about system changes. This feature ensures seamless interaction and efficient temperature management.
3.2 Setting the Time and Day
To set the time and day on the Honeywell RTH221B, press the “Set” button until the time/day begins to flash. Use the up or down arrows to adjust the current time and day. Holding the button speeds up the adjustment. Once set, press “Run” to confirm. The display will show the correct time and day, ensuring accurate scheduling. This feature is essential for programming and maintaining your temperature preferences. Note that after battery replacement, the clock and day must be reset manually, as they are stored in volatile memory.
3.3 Built-in Compressor Protection
The Honeywell RTH221B features built-in compressor protection, designed to prevent damage to your air conditioning or heat pump system. This feature ensures the compressor waits at least five minutes before restarting after shutdown. During this period, the display shows “Cool On” or “Heat On” to indicate the compressor is in a protective delay. This safeguard helps extend the lifespan of your HVAC equipment by reducing wear and tear from frequent starts. The feature is automatically enabled and requires no additional setup, providing peace of mind and system longevity.
3.4 Thermostat Controls and Buttons
The Honeywell RTH221B thermostat features intuitive controls and buttons for easy operation. The “Set” button allows you to adjust the time, day, and program schedule, while the “Hold” button overrides the programmed temperature settings permanently. The “Run” button resumes the program schedule, and the “System Switch” toggles between heating and cooling modes. The “Fan Switch” offers “Auto” or “On” modes for fan operation. Temperature adjustment is done using the up and down buttons, ensuring precise control. These controls provide a user-friendly interface for managing your home’s climate efficiently.
Programming the Thermostat
The Honeywell RTH221B allows programmable scheduling with four daily time periods, enabling different settings for weekdays and weekends. Temporary or permanent overrides are available for flexibility. The display shows the current program period and allows adjustments, ensuring customized temperature control to suit your lifestyle and preferences.
4.1 Understanding the Programming Schedule
The Honeywell RTH221B offers a programmable schedule with four time periods daily, allowing distinct settings for weekdays and weekends. This feature helps reduce energy costs by automating temperature adjustments. Users can set specific temperatures for morning, day, evening, and night, ensuring comfort and efficiency. The pre-set schedule suggests optimal temperatures to minimize heating and cooling expenses. The display clearly shows the active period, making it easy to manage and adjust settings as needed.
4.2 Temporary vs. Permanent Overrides
The Honeywell RTH221B allows users to temporarily or permanently override programmed settings. Temporary overrides adjust the temperature until the next scheduled period, shown by “Temporary” on the display. Permanent overrides, activated by pressing HOLD, disable the program entirely, maintaining the set temperature continuously. To exit temporary mode, press RUN, while permanent mode requires pressing RUN to resume scheduling. This flexibility ensures users can adapt temperature settings to their needs without losing programmed efficiency. The display clearly indicates the active mode, helping users manage overrides effectively.
4.3 Adjusting the Program Schedule
The Honeywell RTH221B allows users to customize their program schedule with up to four time periods daily. Press the Set button to navigate through the schedule and adjust temperatures using the up or down arrows. The display shows the current period, enabling precise adjustments. Weekday and weekend settings can be tailored independently. Pre-set recommendations are provided to optimize energy use. After adjustments, press Run to resume the schedule. This feature ensures flexibility and efficiency, allowing users to align temperature settings with their daily routines. The thermostat also offers a Hold option for permanent overrides if needed. Adjustments are intuitive and user-friendly.
Advanced Settings and Customization
The Honeywell RTH221B offers advanced features like selecting Fahrenheit or Celsius, restoring default settings, and adjusting compressor protection. These options enhance customization for optimal system performance and efficiency.
5.1 Selecting Fahrenheit or Celsius
The Honeywell RTH221B allows users to choose between Fahrenheit and Celsius for temperature display. This feature is easily accessible through the system setup menu. To select, press and hold the appropriate buttons until the display changes. Once set, the thermostat retains this preference, ensuring consistent temperature readings. This customization option accommodates user preferences, making the thermostat versatile for various regions and user needs. The process is straightforward, requiring minimal navigation through the menu, and does not affect other settings. This flexibility enhances user satisfaction and ease of use.
5.2 Restoring Default Settings
To restore the Honeywell RTH221B to its factory default settings, press and hold both the “SET” and “RUN” buttons simultaneously for approximately 5 seconds. This action resets the program schedule, compressor protection settings, and system preferences to their original configuration. Note that the clock and day settings will be lost and must be reconfigured. This feature is useful for troubleshooting or if you wish to start fresh with the thermostat’s programming. Ensure all settings are reprogrammed according to your preferences after performing the reset.
5.3 Compressor Protection Settings
The Honeywell RTH221B features built-in compressor protection, which prevents rapid restarts that could damage your cooling system. This setting forces the compressor to wait 5 minutes before restarting, reducing wear and tear. During this period, the display shows “Cool On” or “Heat On” to indicate the compressor is in a cooldown phase. This feature is enabled by default and is crucial for maintaining the longevity of your HVAC system. Users can adjust or disable this setting via the advanced menu if specific system requirements differ. Always refer to the manual for precise instructions on modifying these settings.
Troubleshooting Common Issues
Address common issues like “Lo Batt” by replacing batteries. Ensure system compatibility and check temperature settings. Refer to the manual for detailed solutions and resets.
6.1 Addressing “Lo Batt” Indications
The “Lo Batt” message indicates low battery levels. Replace the two AAA batteries when this alert appears. Set the system switch to Off before removing the batteries to avoid system activation. Install fresh batteries promptly, as the thermostat will stop functioning once batteries are depleted. The “Lo Batt” warning appears 60 days before batteries run out, allowing ample time for replacement. After replacing, reset the clock and day, as these are not stored in memory. Regular annual replacements are recommended to ensure uninterrupted operation.
6.2 Resolving System Compatibility Problems
If your Honeywell RTH221B thermostat isn’t functioning correctly, ensure it’s compatible with your heating or cooling system. This thermostat works with gas, oil, or electric furnaces, central air conditioners, and hot water systems but isn’t suitable for heat pumps with backup heat or multistage systems. Verify wire connections and system type settings. If issues persist, refer to the installation manual or contact Honeywell customer support at 1-800-468-1502 for assistance. Proper system matching is essential for reliable operation.
6.3 Fixing Temperature Control Malfunctions
If your Honeywell RTH221B thermostat isn’t controlling temperatures correctly, check the temperature settings and ensure the system switch is set to the correct mode (Heat/Cool). Verify that the program schedule is properly configured and that temporary or permanent overrides aren’t interfering. Ensure batteries are fresh, as low battery warnings can disrupt operation. If issues persist, reset the thermostat by removing the batteries and waiting 30 seconds before reinserting them. For further assistance, refer to the user manual or contact Honeywell customer support at 1-800-468-1502.
Maintenance and Care
Regularly replace batteries, clean the display screen, and ensure proper wiring connections. Check for software updates and maintain a dust-free environment around the thermostat for optimal performance.
7.1 Replacing Batteries
To maintain optimal performance, replace the Honeywell RTH221B thermostat batteries annually or when the “Lo Batt” indicator appears. Use two fresh AAA alkaline batteries. Set the system switch to “Off” before removing the old batteries to prevent the heating/cooling system from remaining active. After replacing, reseat the batteries securely and set the clock and day, as these settings are not stored in memory. Properly seated batteries ensure accurate temperature control and prevent display issues. Replace batteries when away for extended periods to avoid system interruptions.
7.2 Ensuring Proper System Operation
Regularly check the Honeywell RTH221B thermostat’s settings and connections to ensure proper system operation. Verify that the system switch matches your heating or cooling setup, whether it’s gas, oil, electric, or a heat pump. Ensure the fan operation switch is correctly set based on your system type—either “Gas/Oil” or “Electric/Heat Pump.” Clean the thermostat’s display and internal components to maintain accuracy. Schedule periodic inspections of wiring and connections to prevent malfunctions. Proper operation ensures efficient heating, cooling, and energy savings, aligning with the thermostat’s designed performance capabilities and user preferences for optimal comfort. Always refer to the user manual for detailed guidance.
7.3 Checking and Cleaning the Thermostat
Regularly inspect and clean the Honeywell RTH221B thermostat to ensure optimal performance. Turn off the power at the circuit breaker before cleaning. Gently wipe the display and exterior with a soft, dry cloth to remove dust and debris. Avoid using harsh chemicals or abrasive materials that could damage the screen or housing. Check for dust buildup inside the thermostat, which can interfere with temperature sensing. Cleaning ensures accurate temperature readings and maintains the thermostat’s functionality. Refer to the user manual for detailed cleaning instructions to preserve your device’s efficiency and longevity. Proper maintenance guarantees reliable operation and extends the product’s lifespan.
Customer Assistance and Support
For assistance, visit http://yourhome.honeywell.com or call Honeywell Customer Care at 1-800-468-1502. Online resources, manuals, and troubleshooting guides are available to support your RTH221B thermostat needs effectively.
8.1 Contacting Honeywell Customer Care
For assistance with your Honeywell RTH221B thermostat, contact Honeywell Customer Care toll-free at 1-800-468-1502. Visit http://yourhome.honeywell.com for online support, manuals, and troubleshooting resources. Before calling, ensure you have your model number and date code readily available. This service is available to address installation, programming, or operational inquiries, ensuring your thermostat functions optimally. Honeywell also offers a one-year warranty on the product, excluding batteries, covering defects in workmanship and materials under normal use.
8.2 Online Resources and Manuals
For comprehensive support, Honeywell provides online resources and downloadable manuals for the RTH221B thermostat. Visit http://yourhome.honeywell.com to access the Instruction Manual (56 pages) and Use and Care Manual. These guides cover installation, programming, and troubleshooting. Additional resources, such as user guides and troubleshooting tips, are also available. PDF manuals for RTH221B models (e.g., RTH221B1000, RTH221B1047) can be downloaded free of charge, ensuring easy access to detailed instructions for optimal thermostat performance and maintenance.
8.3 Warranty Information
Honeywell offers a one-year limited warranty for the RTH221B thermostat, covering defects in materials and workmanship under normal use. The warranty excludes the battery and does not cover removal or reinstallation costs. If the product malfunctions due to defects, Honeywell will repair or replace it. For warranty-related inquiries, contact Honeywell Customer Relations at 1985 Douglas Dr, Golden Valley, MN 55422, or call 1-800-468-1502. This warranty provides specific legal rights, and additional rights may vary by state. Full warranty details are outlined in the product manual.
The Honeywell RTH221B programmable thermostat is a valuable addition to any home, offering ease of use and reliable temperature control. With its energy-efficient design and customizable scheduling options, it helps reduce energy consumption while maintaining comfort. The comprehensive manual provides clear guidance for installation, programming, and troubleshooting. By following the instructions, users can optimize their heating and cooling systems’ performance. Honeywell’s commitment to quality and customer support ensures a hassle-free experience. Make the most of your RTH221B to enjoy consistent comfort and energy savings throughout the year.