Honeywell Home Programmable Thermostat

Owner's Manual

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For help please visit honeywellhome.com

The thermostat features a digital display and control buttons (Set, Hold, Run) for managing heating and cooling systems. It also includes system and fan switches.

Thermostat Diagram Description: The front of the thermostat shows a digital screen displaying time, day, temperature, and system status (e.g., Heat On, Cool On). Below the screen are three main buttons: Set, Hold, and Run. To the right are up and down arrow buttons for temperature adjustment. A System switch (Heat/Off/Cool) and a Fan switch (Auto/On) are typically located on the side or bottom of the unit.

Identify System Type

This thermostat is compatible with the following systems:

• Gas, oil, or electric furnace
• Central air conditioner
• Hot water system with or without pump
• Millivolt system
• Central heating and cooling system
• Heat pump without auxiliary/backup heat

Note: This thermostat cannot be used on heat pumps with backup heat or on multistage systems.

Customer Assistance and Safety Notices

Mercury Recycling Notice: ⚠️ This product does not contain mercury. However, it may replace a product that does. Products containing mercury should not be discarded in household trash. For recycling information in the United States, visit www.thermostat-recycle.org. In Canada, visit www.switchthestat.ca.

Notice: To avoid possible compressor damage, do not run the air conditioner if the outside temperature drops below 50°F (10°C).

For assistance with this product, please visit honeywellhome.com/support. To save time, note your model number and date code before calling. The model number and date code can be found by removing the thermostat from its wallplate and turning it over.

Installation Guide

Follow these steps to install your thermostat:

1. Turn Off Power: Disconnect power to the heating/cooling system at the circuit breaker box or the system power switch.
2. Remove Old Thermostat: Carefully remove the old thermostat, leaving the wallplate and wires attached. If the old thermostat contains a mercury tube, consult specific disposal instructions.
3. Label Wires: As you disconnect wires from the old thermostat, use the provided wire labels to mark each wire according to its terminal designation. A diagram shows the typical wire labels and corresponding terminals (e.g., R, Rc, G, Y, W, C, etc.).
4. Separate Wallplate: Remove the new thermostat from its wallplate.
5. Mount Wallplate: Mount the new wallplate onto the wall using the included screws and anchors. Drill pilot holes as needed for drywall or plaster.
6. Connect Wires: Match the labeled wires to the corresponding terminals on the new wallplate. Refer to the "Alternate Wiring" section if labels do not match terminal letters. A diagram illustrates the wire connections to the terminal block. If you have both R and Rc wires, remove the metal jumper between them.
7. Install Batteries: Install two AAA alkaline batteries into the back of the thermostat.
8. Set Fan Operation Switch: Move the switch to the appropriate setting for your system (Gas/Oil or Electric/Heat Pump).
9. Install Thermostat: Attach the thermostat unit to the mounted wallplate.
10. Turn Power Back On: Restore power to the heating/cooling system.

Advanced Installation

Enter System Setup: To enter system setup, press and hold both the up and down arrow buttons until the display changes (approximately 5 seconds).

Changing Settings:

1. Press the up or down button to change the setting.
2. Press the up and down buttons simultaneously for one second to advance to the next function.
3. Press the RUN button to exit and save settings.

Note: If no button is pressed for 60 seconds during setup, changes are automatically saved and the menu exits.

The thermostat offers various setup functions, including:

• Function 5: System Selection - Choose the correct system type (Gas/Oil furnace, Electric furnace, Heat pump/Hot water/High-efficiency furnace, Gas/oil steam/Gravity system) for optimal operation.
• Function 14: Temperature Display - Select Fahrenheit (°F) or Celsius (°C).
• Function 15: Compressor Protection - Enable (1) or disable (0) compressor protection.
• Function 20: Clock Display - Choose between 12-hour (0) or 24-hour (1) display.
• Function 21 (RTH2300 only): Change Filter Timer - Set a reminder for filter replacement (Off, 30 days, 90 days, 6 months, 9 months, 1 year).
• Function 40 (RTH2300 only): Restore Program Schedule - Reset to default program settings (Off, On).

Compressor Protection: This feature waits approximately 5 minutes before restarting the compressor to prevent damage. During this wait, "Cool On" or "Heat On" will flash on the screen.

About Your New Thermostat

Your new thermostat is designed for reliable service and easy climate control. Key features include:

• Backlit display (RTH2300).
• Displays ambient (measured) temperature at all times.
• One-touch access to setpoint temperature.
• Preset program settings.
• Temporary and permanent schedule override.
• Built-in compressor protection.

Thermostat Controls and Display

Control Buttons:

• Set: Press to set time, day, or program schedule.
• Hold: Press to override programmed temperature control.
• Run: Press to resume program schedule.

System and Fan Switches:

• System Switch: Controls heating or cooling system (Heat, Off, Cool).
• Fan Switch: Controls the fan (Auto: runs with system; On: runs continuously).

Display Screen Elements:

• Setpoint Indicator: Appears when the setpoint temperature is displayed.
• Current Time/Day: Displays the current time and day (RTH2300 only).
• Current Program Period: Shows the active period (Wake, Leave, Return, Sleep).
• System Status: Indicates if the cooling or heating system is active (Cool On, Heat On). Flashing "Cool On" indicates compressor protection is engaged.
• Low Battery Warning: Icon appears when batteries are low.
• Temperature Adjustment: Use up/down arrows to set desired temperature.
• Temperature Display: Shows ambient temperature. Pressing up/down arrows displays setpoint temperature for five seconds.

Programming Your Thermostat

You can program four time periods per day with different schedules for weekdays and weekends. The recommended pre-set settings can help reduce heating/cooling expenses.

Program Schedule Overview:

• Wake: Time you awaken and desired morning temperature.
• Leave: Time you leave home and energy-saving temperature while away.
• Return: Time you return home and desired evening temperature.
• Sleep: Time you go to bed and desired overnight temperature.

Example Pre-set Schedule:

Note: Leave and Return periods can be canceled on weekends for RTH2300 models.

Adjusting Program Schedules:

For RTH2300: Press SET until "Set Schedule" appears. Use arrow buttons to set time and temperature for each period (Wake, Leave, Return, Sleep) for weekdays (Mo-Fr) and then weekends (Sa-Su). Press RUN to save.

For RTH221: Press SET until "Set Schedule" appears. Use arrow buttons to set time and temperature for each period (Wake, Leave, Return, Sleep) for all days (Mo-Su). Press RUN to save.

Program Schedule Override:

• Temporary Override: Press the up or down arrow buttons to adjust the temperature. The change lasts until the next scheduled period. "Temporary" will appear on the display. Press RUN to cancel the override and return to the schedule.
• Permanent Override (Hold): Press the HOLD button to set a constant temperature. This disables the program schedule. The temperature will be maintained until you manually change it or press RUN to cancel "Hold" and resume the schedule.

Filter Change Reminder

If enabled during installation, "Change Filter" will flash on the screen when the filter needs replacement. After replacing the filter, press and hold the RUN button for 3 seconds to reset the alert.

Battery Replacement

Install two fresh AAA batteries when the "Lo Batt" icon appears. Replace batteries annually or before extended absences. Settings are stored in non-volatile memory, but the clock and day may need to be reset after battery replacement. Ensure the System switch is set to OFF before changing batteries.

Electrical Ratings

Troubleshooting

Display is blank: Ensure batteries are installed correctly. Check the circuit breaker.

Heating or cooling system does not respond: Ensure the System switch is set correctly (Heat/Cool) and the desired temperature is set appropriately (higher than ambient for heat, lower for cool). Allow 5 minutes for the system to respond.

Temperature settings do not change: Verify that heating and cooling temperatures are set within acceptable ranges (Heat: 40°-90°F / 4.5°-32°C; Cool: 50°-99°F / 10°-37°C).

"Cool On" or "Heat On" is flashing: Compressor protection is engaged. Wait 5 minutes for the compressor to restart safely.

"Heat On" not displayed: Set System switch to Heat and temperature level above ambient.

"Cool On" not displayed: Set System switch to Cool and temperature level below ambient.

For further assistance, visit honeywellhome.com/support.

Warranty

This product comes with a 1-year limited warranty. For details, visit honeywellhome.com/support.

Manufacturer Information

Resideo Technologies Inc. 1985 Douglas Drive North, Golden Valley, MN 55422

© 2020 Resideo Technologies, Inc. All rights reserved.