RTH230B User Manual: A Comprehensive Guide
Welcome! This manual guides you through setup, operation, and maintenance of your Honeywell RTH230B thermostat, ensuring optimal performance and energy savings.
The Honeywell RTH230B is a widely-used programmable thermostat designed for efficient home climate control. This model offers reliable performance and user-friendly operation, making it suitable for various heating and cooling systems. It allows for customized scheduling to optimize comfort and reduce energy consumption.
This manual provides comprehensive instructions, from initial setup and wiring to advanced programming features. Whether you’re a first-time thermostat user or experienced with programmable controls, this guide will help you maximize the benefits of your RTH230B. Understanding its capabilities ensures a comfortable and cost-effective home environment. Remember to consult the safety precautions before installation and operation.
Unboxing and Package Contents
Upon opening your Honeywell RTH230B package, carefully verify that all components are present and undamaged. The standard package should include the thermostat base, the programmable thermostat unit itself, a mounting plate, wire labels for easy identification during installation, and this comprehensive user manual.
Additionally, you should find screws and anchors for secure wall mounting. Some packages may also contain batteries, though it’s always prudent to have fresh ones on hand. If any items are missing or appear damaged, immediately contact the retailer or Honeywell customer support. Retain the original packaging for potential returns or warranty claims. A complete inventory ensures a smooth installation process.
Safety Precautions
Prior to installing or servicing your Honeywell RTH230B thermostat, always disconnect power to your heating and cooling system at the breaker box to avoid electrical shock. This is a crucial safety step. Do not attempt repairs beyond the scope of this manual; contact a qualified HVAC technician for complex issues.
Keep the thermostat dry and avoid exposing it to extreme temperatures or direct sunlight. This product is designed for indoor use only. Ensure wiring connections are secure and comply with local electrical codes. Improper installation can lead to system malfunction or safety hazards. Follow all instructions carefully and prioritize personal safety throughout the process.

Installation Guide
Begin installation by carefully following these steps: mounting the base, connecting the wiring, inserting batteries, and powering on for initial setup.
Mounting the Thermostat Base
Proper mounting is crucial for accurate temperature sensing and reliable operation. First, switch off power to your heating/cooling system at the breaker. Remove your old thermostat, carefully noting the wire connections – a photo is helpful! Use the included mounting screws and wall anchors to securely attach the RTH230B baseplate to the wall.

Ensure the base is level for a professional appearance and accurate readings; Feed the thermostat wires through the opening in the baseplate. Double-check that no wires are pinched or damaged during this process. The baseplate should be positioned away from direct sunlight, drafts, or other sources of interference that could affect temperature readings. A stable and level mounting ensures optimal performance of your new Honeywell thermostat.
Wiring Diagram and Connections
Carefully connect the wires to the corresponding terminals on the thermostat base, referencing the wiring diagram included with your RTH230B. Common terminals include Rh (power), Rc (cooling power), W (heating), Y (cooling), and G (fan). If you have a C-wire (common wire), connect it to the ‘C’ terminal for consistent power.
Incorrect wiring can damage your system! If unsure, consult a qualified HVAC technician. Ensure each wire is securely inserted into its terminal. Gently tug on each wire to confirm a solid connection. Double-check your connections against the diagram before restoring power. A properly wired thermostat is essential for safe and efficient operation of your heating and cooling system.
Battery Installation
The RTH230B requires two AA alkaline batteries for backup power and to maintain settings during power outages. Locate the battery compartment on the thermostat base – typically at the bottom or side. Open the compartment cover and insert the batteries, ensuring correct polarity (+ and -) as indicated inside.
Use only fresh, non-rechargeable AA alkaline batteries for optimal performance. Avoid mixing old and new batteries. Properly aligned batteries ensure reliable operation. Close the battery compartment cover securely. The thermostat will display a battery icon indicating battery status. Replace batteries when the low battery indicator appears to prevent loss of settings.
Powering On and Initial Setup
After battery installation, the RTH230B should power on automatically. If not, verify battery polarity and ensure they are fresh. The display will illuminate, initiating the setup process. You’ll be prompted to set the current date and time. Use the up and down buttons to adjust the values, and the ‘Set’ or ‘Confirm’ button to save each setting.
Next, the thermostat may ask for your zip code to accurately determine local weather conditions. Follow the on-screen instructions to complete this step. Finally, select your heating and cooling system type. Proper setup ensures accurate temperature control and efficient operation. Refer to the wiring diagram if needed.

Understanding the Display and Controls
Explore the intuitive interface! This section details the LCD screen’s icons and button functions, enabling effortless temperature adjustments and programming.
LCD Screen Overview
The RTH230B’s LCD screen provides essential information at a glance. You’ll find the current room temperature prominently displayed, alongside the setpoint temperature – the temperature the thermostat is actively working to achieve. Icons indicate the current heating or cooling mode, whether the system is actively running, and battery status.
A clock displays the current time, crucial for scheduled programming. Additional icons may illuminate to signal features like a temporary hold or a filter change reminder. The display clearly shows if the thermostat is in manual or auto mode. Understanding these indicators allows for quick assessment of your home’s climate control status and efficient operation of the thermostat. Familiarize yourself with each icon for optimal use.
Button Functions Explained
The RTH230B features intuitive button controls for easy operation. The “Up” and “Down” buttons adjust the setpoint temperature, increasing or decreasing it as desired. The “Mode” button cycles through heating, cooling, and off settings, allowing you to select your preferred climate control. “Hold” temporarily overrides the programmed schedule, maintaining a constant temperature.
The “Run” button confirms selections and activates programmed settings. Use “Set/Menu” to access programming options like date, time, and scheduling. A brief press displays current settings, while a longer press enters the menu. Understanding each button’s function ensures effortless control over your home’s temperature and maximizes energy efficiency.
Temperature Display Units (Fahrenheit/Celsius)
The RTH230B thermostat allows you to display temperatures in either Fahrenheit (°F) or Celsius (°C), catering to personal preference and regional standards. To switch between units, navigate to the thermostat’s settings menu using the “Set/Menu” button. Within the menu, locate the “Temperature Units” option.
Use the “Up” or “Down” buttons to toggle between Fahrenheit and Celsius. Confirm your selection with the “Run” button. The display will immediately reflect the chosen unit. This flexibility ensures comfortable and accurate temperature readings, regardless of your familiarity with either scale. Remember to note the selected unit for accurate temperature interpretation.

Programming the Thermostat
Customize your comfort! Easily set schedules, temporary holds, and permanent holds to optimize heating and cooling, saving energy and maximizing convenience.
Setting the Current Date and Time
Accurate time is crucial for proper scheduling. To set the date and time on your Honeywell RTH230B, navigate to the ‘Set Date/Time’ option within the thermostat’s menu. Use the up and down arrow buttons to adjust the month, day, and year. Confirm each selection by pressing the ‘Set’ or ‘OK’ button.
Next, adjust the hour and minute, again confirming each selection. Ensure you correctly identify AM or PM. Some models may offer a 24-hour clock format option within the settings. Incorrect date and time settings will affect programmed schedules, leading to inaccurate heating and cooling cycles. Double-check your entries for accuracy before exiting the settings menu.

Creating a Heating/Cooling Schedule
Programmed schedules maximize energy efficiency and comfort. Access the ‘Schedule’ menu on your RTH230B. You’ll typically define separate schedules for weekdays and weekends, or create a unique 7-day schedule. For each period (Wake, Leave, Return, Sleep), set the desired temperature for both heating and cooling modes.
Use the arrow buttons to adjust temperatures and the ‘Set’ or ‘OK’ button to confirm. Consider your daily routines when setting these periods. For example, lower the temperature while you’re away and at night. Review your schedule carefully to ensure it aligns with your preferences and lifestyle, optimizing both comfort and energy savings.
Temporary Hold Function
The Temporary Hold allows you to override the programmed schedule for a specified duration. Press the ‘Hold’ button on your RTH230B. This will prompt you to enter a desired temperature using the arrow keys. The thermostat will maintain this temperature until the next scheduled program period begins.
This is ideal for unexpected changes in your routine, like a spontaneous evening at home or a late return from work. The duration of the hold is automatically determined by the programmed schedule. After the hold period ends, the thermostat seamlessly resumes its regular programming, ensuring continued energy efficiency and comfort.
Permanent Hold Function
Utilizing the Permanent Hold feature on your Honeywell RTH230B overrides the programmed schedule indefinitely. After activating ‘Hold’, set your preferred temperature with the up/down arrow keys. Unlike the Temporary Hold, this setting remains active until you manually cancel it and revert back to the scheduled program.
This is useful for extended periods where a consistent temperature is desired, such as during vacations or when seasonal changes necessitate a new, unchanging setting. To cancel the Permanent Hold, simply press the ‘Hold’ button again, returning the thermostat to its regularly programmed operation. Remember to adjust your schedule accordingly!

Advanced Features
Explore enhanced capabilities! Discover energy-saving modes, filter reminders, backlight controls, and swing temperature adjustments for personalized comfort and efficiency.
Energy Saving Modes
Optimize your energy consumption with the RTH230B’s intelligent energy saving modes. These features are designed to reduce heating and cooling costs without sacrificing comfort. The thermostat offers pre-programmed energy saving settings, automatically adjusting temperatures during periods of low activity, like when you are asleep or away from home.
You can customize these settings to perfectly match your lifestyle and preferences. Explore options for scheduling temperature setbacks during specific times of the day or week. By utilizing these modes, you actively contribute to a smaller carbon footprint and lower monthly utility bills. The RTH230B empowers you to take control of your energy usage, promoting both environmental responsibility and financial savings.
Filter Change Reminder
Maintain optimal air quality and system efficiency with the RTH230B’s convenient filter change reminder. A dirty air filter restricts airflow, forcing your heating and cooling system to work harder, increasing energy consumption and potentially leading to costly repairs. The thermostat allows you to set a reminder based on time or usage – typically every 1-3 months, depending on your environment and filter type.
When the reminder activates, a clear notification will appear on the LCD screen, prompting you to replace the filter. Regularly changing your filter ensures cleaner air, improved system performance, and extended equipment lifespan. This simple maintenance task contributes significantly to long-term savings and a healthier home environment.
Backlight Control
Enhance visibility in low-light conditions with the RTH230B’s adjustable backlight feature. The thermostat’s LCD screen is easily readable, even in darkness, thanks to the integrated backlight. You can customize the backlight settings to suit your preferences and conserve energy.
Options typically include turning the backlight on permanently, activating it with a button press, or setting it to automatically illuminate when the thermostat detects low ambient light. Adjusting these settings is straightforward through the thermostat’s menu system. A brighter backlight improves readability, while a dimmer setting extends battery life. Optimize your viewing experience and energy efficiency with personalized backlight control.
Swing Temperature Adjustment
Fine-tune your comfort with the RTH230B’s swing temperature adjustment feature. This setting controls the temperature range around your setpoint before the heating or cooling system activates. A smaller swing temperature provides more consistent temperatures, minimizing fluctuations and enhancing comfort. Conversely, a larger swing temperature allows for greater temperature variation, potentially saving energy.
Adjusting the swing temperature is done through the thermostat’s menu. Experiment with different settings to find the optimal balance between comfort and energy efficiency for your home. Understanding this feature allows you to personalize the thermostat’s operation to perfectly match your needs and preferences, ensuring a consistently comfortable environment.

Troubleshooting Common Issues
Resolve quickly! This section offers solutions for typical problems like power failures, inaccurate readings, connectivity issues, and error code interpretations.
Thermostat Not Powering On
Problem: If your RTH230B thermostat displays a blank screen or shows no signs of life, several factors could be at play. First, verify battery installation – ensure they are fresh and correctly positioned.
Next, check the circuit breaker supplying power to your HVAC system; a tripped breaker will prevent operation. Inspect wiring connections at both the thermostat base and the furnace/air handler, looking for loose or disconnected wires.
Confirm the C-wire (common wire) is properly connected, as this is crucial for consistent power. If a C-wire isn’t present, a C-wire adapter might be necessary. Finally, test the transformer to ensure it’s delivering the correct voltage. If issues persist, consult a qualified HVAC technician.
Incorrect Temperature Readings
Issue: If the RTH230B displays temperatures significantly different from the actual room temperature, several causes are possible. First, ensure the thermostat isn’t exposed to direct sunlight, drafts, or heat sources like lamps. These can skew readings.
Check for obstructions blocking airflow around the thermostat. Verify proper calibration; some models allow temperature offset adjustment. Confirm correct placement – avoid exterior walls or areas with poor circulation.
Inspect wiring for loose connections, as this can sometimes cause erratic behavior. If the problem continues, try resetting the thermostat to factory defaults. If discrepancies remain, consider a replacement thermostat, as the internal temperature sensor may be faulty.
Connectivity Problems
Issue: While the RTH230B is a basic, non-connected thermostat, connectivity issues can arise if attempting integration with external systems (unofficial methods). Ensure proper wiring if interfacing with a third-party hub. Verify compatibility; the RTH230B lacks built-in Wi-Fi.
If using a relay or adapter, check its power supply and connections. Confirm the hub’s software is updated and correctly configured to recognize the thermostat’s signals. Troubleshoot the hub itself – restart it and check its network connection.
Remember, the RTH230B is designed for standalone operation; complex connectivity may be unreliable.
Display Errors and Codes
Error messages on the RTH230B’s LCD screen indicate potential issues. A blank display usually signifies a power problem – check batteries or wiring. “Low Battery” prompts immediate replacement. If the display shows unusual characters or is dim, try resetting the thermostat by removing and reinserting batteries.
While the RTH230B doesn’t feature extensive error codes, consistently incorrect temperature readings suggest a faulty sensor or improper location. Flashing display could indicate a wiring fault. Consult a qualified HVAC technician if errors persist after basic troubleshooting.
Refer to the full manual for detailed explanations.

Maintenance and Care
Regular cleaning and timely battery replacements ensure optimal performance; Store the thermostat properly when not in use for extended periods, protecting it from extremes.
Cleaning the Thermostat
Maintaining a clean thermostat is crucial for accurate readings and optimal performance. Before cleaning, always power off the thermostat to prevent electrical shock or damage. Use a soft, dry cloth to gently wipe the thermostat’s surface. Avoid abrasive cleaners, solvents, or excessive moisture, as these can harm the display and internal components.
For stubborn dirt or grime, lightly dampen the cloth with water, ensuring it’s not dripping wet. Carefully wipe the affected areas, then immediately dry with a clean, dry cloth. Do not spray any liquids directly onto the thermostat. Pay particular attention to the LCD screen, using a gentle touch to avoid scratches. Regular dusting will prevent buildup and maintain a clear display. Avoid using compressed air, as it can push dust and debris into the thermostat’s internal mechanisms.
Battery Replacement Schedule
Regular battery replacement ensures uninterrupted thermostat operation. The Honeywell RTH230B typically requires battery changes once a year, though usage and battery quality can affect this timeframe. The thermostat will usually display a low battery warning icon when power is dwindling, prompting replacement.
It’s a good practice to replace batteries during seasonal changes, like when adjusting for daylight saving time. Use fresh alkaline batteries of the correct size, as specified in the manual. Avoid mixing old and new batteries. Properly dispose of used batteries according to local regulations. Even if the thermostat appears functional, proactively replacing batteries prevents unexpected shutdowns and maintains accurate temperature control. Consider setting a calendar reminder to facilitate timely battery changes.
Long-Term Storage Instructions
If storing your Honeywell RTH230B for an extended period, proper preparation is crucial. Remove the batteries to prevent corrosion and potential damage to the thermostat’s internal components. Disconnect the wiring carefully, labeling each wire for easy reconnection later. Store the thermostat in a cool, dry place, away from direct sunlight and extreme temperatures.
Keep it in its original packaging, if available, or a protective container. Avoid storing near dust, moisture, or potential physical impacts. Before reusing, inspect the thermostat and wiring for any signs of damage. Replace batteries even if they were removed in good condition, as self-discharge can occur during storage. Refer to the installation guide for reconnection instructions.

Gmail Account Integration (Related Information)
Gmail Login Access
Accessing Gmail is crucial for Honeywell support resources related to your RTH230B thermostat. To login, navigate to mail.google.com. You’ll be prompted to enter your Google account email or phone number, followed by your password.
Security is paramount: If using a public computer, always select the “Sign out” option upon completion to protect your account. Google provides guidance on secure login practices for unfamiliar devices. Remember to regularly review your account activity and security settings.
Account Recovery: Should you encounter login issues, utilize Google’s account recovery options. These include verifying your identity through a recovery email or phone number. For further assistance, explore the official Gmail Help Center for comprehensive tutorials and FAQs.
Gmail Account Recovery
Recovering your Gmail access is vital if you encounter login difficulties while accessing Honeywell support or documentation related to your RTH230B thermostat. Google offers several recovery methods. Begin by clicking the “Forgot password?” link on the Gmail sign-in page.
Verification Options: You’ll be guided through options like receiving a verification code via a recovery email address or phone number previously linked to your account. Answer security questions if configured. If these fail, Google provides a more detailed account recovery form.
Account Verification: Be prepared to provide as much accurate information as possible to verify your ownership. The Gmail Help Center offers extensive resources and troubleshooting steps for successful account recovery. Prioritize account security to minimize recovery needs.
Gmail Security Tips
Protecting your Gmail account is crucial when accessing Honeywell RTH230B thermostat support resources and manuals online. Enable two-factor authentication (2FA) for an extra layer of security, requiring a code from your phone in addition to your password.
Strong Passwords: Use a strong, unique password for your Gmail account – a combination of uppercase and lowercase letters, numbers, and symbols. Avoid reusing passwords across multiple sites. Regularly review connected apps and revoke access to those you no longer use.
Phishing Awareness: Be cautious of phishing emails attempting to steal your login credentials. Never click on suspicious links or provide personal information in response to unsolicited requests. Keep your recovery information updated.
Gmail Help Center Resources
Accessing Gmail’s official Help Center provides valuable assistance while troubleshooting issues related to your Honeywell RTH230B thermostat’s online manual access. The center offers tutorials on using Gmail features, managing settings, and resolving common problems.
Account Recovery: Find detailed instructions on recovering your account if you’ve forgotten your password or lost access. Explore guides on setting up account recovery options, like a recovery email or phone number. Learn about Gmail’s security features and how to protect your account from unauthorized access.
Troubleshooting: Search for solutions to specific issues, such as email delivery problems or spam filtering. Utilize the Help Center’s FAQ section for quick answers to frequently asked questions. Link to Gmail Help















































































