honeywell rth111b manual
Honeywell RTH111B Manual: A Comprehensive Guide (Updated 12/13/2025)
Today’s date is 12/13/2025․ This manual serves as your essential guide for operating and maintaining the Honeywell RTH111B, ensuring optimal performance and comfort․
Welcome! The Honeywell RTH111B is a widely-used, programmable thermostat designed for reliable and efficient home climate control․ This thermostat offers a user-friendly interface, allowing for customized heating and cooling schedules to maximize comfort and minimize energy consumption․
This guide provides comprehensive instructions for installation, operation, programming, and troubleshooting․ Whether you’re a homeowner or a professional installer, this manual will equip you with the knowledge to effectively utilize all the features of your RTH111B․
The RTH111B is compatible with a variety of heating and cooling systems, offering flexibility for diverse home setups․ Understanding its capabilities will empower you to create a comfortable and energy-efficient living environment․ Let’s begin exploring the features and functions of your new thermostat!
What’s Included in the Box
Upon opening your Honeywell RTH111B package, please verify that all components are present․ The box should contain the following items:
- Honeywell RTH111B Thermostat: The main unit with the LCD display and control buttons․
- Thermostat Baseplate: The mounting plate for securing the thermostat to the wall․
- Screws and Wall Anchors: For securely attaching the baseplate to various wall types․
- Wire Labels: Small adhesive labels to help identify the wires during installation․
- This User Manual: Your comprehensive guide to setup, operation, and troubleshooting․
Carefully inspect each item for any signs of damage․ If any components are missing or damaged, please contact Honeywell Support immediately for assistance․ Retain the original packaging for potential returns or warranty claims․
Safety Precautions & Warnings
Important Safety Instructions: Before installing or operating your Honeywell RTH111B thermostat, please read and understand these crucial safety precautions․ Electrical Hazard: Disconnect power to your heating and cooling system at the breaker box before beginning any wiring․ Failure to do so could result in electrical shock or damage to equipment․
Professional Installation Recommended: If you are uncomfortable with electrical wiring, consult a qualified HVAC technician․ Improper wiring can lead to system malfunction or safety hazards․ Keep the thermostat dry and avoid exposing it to extreme temperatures․ This device is intended for indoor use only․ Do not disassemble or attempt to repair the thermostat yourself․
Installation & Wiring
Begin installation by ensuring power is OFF at the breaker․ Carefully follow the wiring diagram for your specific heating and cooling system configuration․
Compatible Systems (Heating & Cooling)
The Honeywell RTH111B thermostat is designed for broad compatibility with most 24-volt heating and cooling systems․ Specifically, it supports single-stage and multi-stage conventional heating systems, including gas, oil, and electric furnaces․
For cooling, it works seamlessly with central air conditioners and heat pumps, though heat pump compatibility may require specific wiring configurations – consult a professional if unsure․
It is NOT compatible with line voltage systems (110V/220V) or millivolt systems․ Before installation, verify your system’s voltage to avoid damage․ The RTH111B is ideal for homes with forced air, hot water, or steam heating, and standard central air conditioning setups․ Always double-check your existing wiring to ensure a proper match․
Wiring Diagram – Detailed Explanation
The RTH111B utilizes a standard 5-wire connection․ Rh connects to the heating power, Rc to the cooling power․ W controls the heating, Y the cooling, and G the fan․
If your system uses a common wire (C), connect it to the ‘C’ terminal; this provides constant power and enhances functionality․ Without a C-wire, some features may be limited․
Carefully match the wire colors to the corresponding terminals․ Incorrect wiring can damage the thermostat or your HVAC system․ If you have a heat pump, additional wiring may be needed for reversing valve control․ Always power off the HVAC system at the breaker before making any connections․ A detailed diagram is included within the packaging for visual guidance․
Mounting the Thermostat Base
Before mounting, ensure the HVAC system power is OFF at the breaker․ Use the included mounting screws and wall anchors for secure installation․ Position the base plate on the wall, ensuring it’s level for accurate temperature readings․
Mark the screw locations with a pencil, then drill pilot holes if necessary․ Insert the wall anchors into the holes, then attach the base plate using the screws․
Ensure the base is firmly attached and doesn’t wobble․ Route the thermostat wires through the opening in the base plate․ A properly mounted base is crucial for stable operation and accurate temperature control․ Double-check all connections before proceeding․
Installing Batteries & Powering On
The Honeywell RTH111B requires two AA batteries for operation, even with a common wire (C-wire) connected․ Insert the batteries into the battery compartment, observing the correct polarity (+ and -) as indicated․
Once the batteries are installed, the thermostat display should illuminate․ If it doesn’t, double-check the battery polarity and ensure the batteries are fresh․ If a C-wire is connected, the thermostat will draw primary power from the HVAC system, with batteries serving as backup․
Power on the HVAC system at the breaker․ The thermostat should now display the current temperature and operating mode․ Verify proper functionality before proceeding with programming․
Understanding the Display & Controls
The RTH111B features a clear LCD display and intuitive buttons for effortless operation․ Familiarize yourself with icons and controls for optimal use․
LCD Display Icons & Meanings
The Honeywell RTH111B’s LCD display utilizes several icons to convey system status at a glance․ A flame icon indicates active heating, while a snowflake signifies cooling is in progress․ A fan icon shows the fan is running, and its status (auto or on) is also displayed․
Battery indicators alert you to low battery levels, prompting replacement․ The “Hold” icon illuminates when a temporary or permanent hold is active, overriding the programmed schedule․ A clock icon confirms the current time is accurately set․
Understanding these icons is crucial for quickly assessing your home’s climate control․ Refer to the display for immediate feedback on system operation and any potential issues requiring attention․ A flashing icon often indicates a specific condition or error needing investigation․
Button Functions: Mode, Temp Up/Down, Hold
The Honeywell RTH111B features intuitive button controls for easy operation․ The “Mode” button cycles through available system settings: Heat, Cool, Auto, and Off․ Use the “Temp Up” and “Temp Down” buttons to adjust the desired temperature, displayed prominently on the LCD screen․ Increments are typically one degree Fahrenheit․
The “Hold” button allows you to temporarily override the programmed schedule, maintaining a constant temperature․ Pressing “Hold” again typically cancels the temporary hold, reverting to the scheduled program․ A prolonged press may activate a permanent hold․
Familiarize yourself with these buttons to effortlessly manage your home’s comfort levels․ Experimenting with each function will quickly reveal the thermostat’s responsive and user-friendly design․
Backlight Control & Settings
The Honeywell RTH111B thermostat incorporates a convenient backlight feature for enhanced visibility in low-light conditions․ Typically, the backlight activates automatically with button presses, illuminating the LCD display for easy reading․ Some models offer adjustable backlight settings, allowing you to customize the brightness or duration․
To access backlight settings (if available), navigate through the thermostat’s menu using the Mode and Temp buttons․ Look for options related to “Display” or “Backlight;” You may be able to choose between different brightness levels or set the backlight to remain continuously on․
Conserving battery life is important; consider utilizing the automatic backlight feature to minimize energy consumption․
Programming Your RTH111B
Effortlessly customize your comfort! This section details how to set schedules, utilize hold functions, and activate vacation mode for optimal temperature control․
Setting the Current Date & Time
Accurate timekeeping is crucial for proper scheduling․ To set the date and time on your Honeywell RTH111B, begin by pressing the “Mode” button until the display shows “Set Date”․
Use the “Temp Up/Down” buttons to adjust the month, then press “Mode” again to select the day․ Continue this process for the year, hour, and minute․
Confirm each selection by pressing “Mode” after each adjustment․ The thermostat will automatically save your settings․
Ensure the correct AM/PM designation is selected during hour setting․ A properly configured date and time ensures your programmed schedules operate as intended, maximizing energy savings and comfort throughout your home․
Creating a 7-Day Programmable Schedule
The RTH111B allows for a unique temperature schedule for each day of the week, maximizing comfort and energy efficiency․ Begin by pressing “Mode” until “Set Schedule” appears․
Select the day you wish to program using the “Temp Up/Down” buttons․ Then, press “Mode” to enter the time and temperature settings for the first period of that day – typically “Wake”․
Adjust the time and temperature using the “Temp Up/Down” buttons, confirming each with “Mode”․ Repeat this process for “Leave”, “Return”, and “Sleep” periods․
Once programmed, the thermostat will automatically follow this schedule․ Repeat for each day to create a personalized, 7-day heating and cooling plan․
Temporary Hold vs․ Permanent Hold
The Honeywell RTH111B offers two hold options for overriding your programmed schedule: Temporary and Permanent․ A “Temporary Hold” maintains the selected temperature until the next scheduled programming period․
To activate, simply adjust the temperature using the “Temp Up/Down” buttons, and the thermostat will hold that setting until the next programmed change․ A “Permanent Hold”, however, overrides the schedule indefinitely․
To set a Permanent Hold, press and hold the “Hold” button until the display indicates “Permanent Hold”․ The thermostat will maintain this temperature until you manually cancel the hold by pressing “Hold” again․
Understanding this distinction allows for flexible temperature control, catering to both short-term and long-term needs․
Vacation Mode: Setting & Usage
The Honeywell RTH111B’s “Vacation Mode” is designed to save energy while you’re away from home for extended periods․ Activating this mode sets a lower heating temperature and a higher cooling temperature, minimizing energy consumption․
To enter Vacation Mode, press the “Mode” button until “Vacation” appears on the display․ Then, use the “Temp Up/Down” buttons to set your desired vacation temperature․ The thermostat will maintain this temperature until you exit Vacation Mode․
To cancel Vacation Mode, simply press the “Mode” button again until your regular programmed schedule resumes․ This feature is ideal for longer absences, ensuring comfort upon your return and reducing utility bills․
Advanced Features & Troubleshooting
Explore enhanced functionalities and solutions to common issues with your Honeywell RTH111B․ This section details filter resets, calibration, error codes, and factory defaults․
Filter Change Reminder – How to Reset
The Honeywell RTH111B thermostat features a helpful filter change reminder, ensuring optimal air quality and system efficiency․ After replacing your air filter, you’ll need to reset this reminder․ To do so, press and hold the “Hold” button for approximately five seconds․
You’ll notice the filter icon on the LCD display begin to flash․ Continue holding the button until the flashing stops and the icon disappears․ This confirms the reminder has been successfully reset․ Ignoring the filter change reminder can lead to reduced airflow, increased energy consumption, and potential damage to your HVAC system․ Regularly scheduled filter replacements are crucial for maintaining a healthy and efficient home environment․
Temperature Calibration – Adjusting Accuracy
The Honeywell RTH111B allows for temperature calibration, enabling you to fine-tune the thermostat’s readings for greater accuracy․ If you suspect the displayed temperature differs from a trusted thermometer, you can adjust it․ Access the calibration mode by simultaneously pressing and holding the “Mode” and “Temp Down” buttons for five seconds․
The display will show the current temperature offset․ Use the “Temp Up” and “Temp Down” buttons to increase or decrease the offset in one-degree increments․ Once you’ve set the desired offset, press the “Mode” button to save the calibration․ Accurate temperature readings are vital for consistent comfort and efficient heating/cooling․
Common Error Codes & Solutions
The Honeywell RTH111B displays error codes to indicate potential issues․ “Lo” signifies low batteries; replace them immediately․ “Hi” indicates a short circuit in the wiring – consult a qualified technician․ A flashing “Call for Heat/Cool” icon, despite proper settings, suggests a system malfunction; check your furnace or air conditioner․
If the display shows “Err”, attempt a thermostat reset by removing and reinserting the batteries․ Persistent errors require professional assistance․ Always disconnect power before inspecting wiring․ Ignoring error codes can lead to system damage or inefficient operation․ Refer to the full troubleshooting section for detailed guidance and safety precautions․
Resetting the Thermostat to Factory Defaults
To restore your Honeywell RTH111B to its original factory settings, simultaneously press and hold the “Mode” and “Temp Down” buttons for five seconds․ The display will briefly flash, confirming the reset․ This action clears all programmed schedules, temperature preferences, and custom settings, returning the thermostat to its out-of-the-box configuration․
Maintenance & Support
Regular cleaning and battery checks ensure optimal performance․ For further assistance, Honeywell provides comprehensive support resources and contact information for users․
Cleaning the Thermostat
Maintaining a clean thermostat is crucial for accurate temperature readings and overall longevity․ Before cleaning, always ensure the system is switched off at the breaker to prevent electrical shock; Use a soft, dry cloth to gently wipe the thermostat’s faceplate and casing․
Avoid using liquid cleaners, abrasive materials, or strong chemicals, as these can damage the LCD display and plastic components․ For stubborn dirt, lightly dampen the cloth with water, ensuring it’s wrung out thoroughly to prevent moisture from entering the unit․
Pay attention to the vents around the thermostat, carefully dusting them to ensure proper airflow․ Regular cleaning, approximately every three months, will help keep your Honeywell RTH111B functioning optimally and looking its best․
Battery Replacement Guide
The Honeywell RTH111B typically requires two AA alkaline batteries for operation․ A low battery indicator will appear on the LCD display, signaling the need for replacement․ Always use fresh, high-quality alkaline batteries for optimal performance․
To access the battery compartment, gently remove the thermostat faceplate from the base․ Locate the battery compartment and observe the correct polarity (+ and -) markings․ Insert the new batteries accordingly․
After replacing the batteries, reattach the faceplate securely․ The thermostat should power on automatically․ If it doesn’t, double-check the battery installation and ensure proper contact․ Dispose of old batteries responsibly, following local regulations․
Honeywell Support Contact Information & Resources
For comprehensive assistance with your Honeywell RTH111B thermostat, several support channels are available․ Visit the Honeywell Home website at honeywellhome․com for FAQs, troubleshooting guides, and downloadable manuals․
You can also reach Honeywell’s support team directly via phone at 1-800-468-1513․ Their representatives are available during standard business hours to address your queries․ For online support, explore the Honeywell community forums where users share solutions and tips․
Additional resources include instructional videos on YouTube and detailed articles on various home automation websites․ Remember to have your model number readily available when contacting support for faster assistance․