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To switch a Honeywell thermostat from cooling to heating, select Heat on its System or mode control. If your thermostat has a physical SYSTEM switch, move it from COOL to HEAT. Then set the target temperature above the room temperature to call for heat. The exact controls vary by model, so use the matching manual if your thermostat’s labels or menus differ.
Switch the thermostat to Heat
Choose the method that matches your thermostat’s controls; there is no single button sequence for every Honeywell model.
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Models with a physical SYSTEM switch
On the PRO TH4110B, move the SYSTEM switch to Heat. Its other positions are Cool and Off: Heat controls the heating system, Cool controls the cooling system, and Off turns both off. Other thermostats may have different labels or capabilities, so check your model’s manual.
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Use the thermostat’s System or mode control and select Heat. The control may be on the home screen or in a menu, depending on the model. For example, the RTH6400 supports manual Heat/Off/Cool changeover and can also offer Auto changeover when enabled. Do not change installer settings just to select Heat.
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- 7-Day Flexible Scheduling or Location Based Temperature Control. It’s your choice. 7-day scheduling programs your thermostat. Geofence technology helps make you comfortable by using your smartphone’s location to know when you’re away and when you return.
- Auto Home and Away Mode. Enjoy ideal temperatures at home, then save when away.
- ENERGY STAR certified. Help save energy, track your heating and cooling with monthly energy reports and get personalized tips on reducing energy use.
Set the temperature to call for heat
After selecting Heat, raise the setpoint above the displayed room temperature. If the target temperature is not higher than the room temperature, the thermostat may have no reason to call for heating. If your thermostat follows a schedule, check whether the schedule or a temporary hold is changing the target temperature.
How to identify your Honeywell model
Controls and available modes vary across Honeywell product families. On the PRO 1000, the manual says to pull the thermostat from the wallplate and turn it over to find the model number. The identification method may differ on other families; check the unit’s label, its manual, or Honeywell Home support. Match the manual to the full model number rather than relying on a similar-looking thermostat.
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- ENERGY STAR certified to help save energy, track your heating and cooling and send personalized tips on reducing energy use..Includes : Thermostat, Wall Plate, Screws, Anchors, Quick Start Guide, Thermostat ID Card, Wire Labels, User Guide
- SAVE ENERGY AND GET REWARDED by checking with your energy provider about available energy savings rebates to save on your purchase (rebate finder link above). Plus, eligible customers can enroll in ongoing energy savings incentives with their energy provider to keep saving all year long.
- CONTROL FROM ANYWHERE by using the app or compatible smart home partners including AMAZON ALEXA, GOOGLE ASSISTANT, MICROSOFT CORTANA, and more. Flexible programming options are also available if you'd rather set it and forget it but still benefit from energy savings.
- CUSTOMIZABLE COLOR SCREEN: Easily change the high-definition display of the Wi-Fi thermostat to any color you choose.
- ON-SCREEN COMFORT INFORMATION: See indoor and outdoor temperature and humidity information right on the home screen, plus daily weather forecast available on the smart thermostat.
Some models support heat pumps or emergency and auxiliary heat, while others do not. Use the mode labels shown for your thermostat and equipment; do not select an emergency or auxiliary heat option unless your model and heating system support it.
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Heat tells the thermostat to control heating. Auto, when available, lets the thermostat choose between heating and cooling based on indoor temperature and configured thresholds. Auto availability and setup are model-specific: the RTH6400 manual describes it as an optional changeover mode, and the RTH8500 guide documents a separate installer setting for enabling or disabling System Changeover. You generally do not need Auto or an installer setting to switch the thermostat to Heat.
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- The screen is brightly backlit with a cool blue color and provides an easy-to-read indoor temperature, including indoor humidity readouts.
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- The advanced design of this thermostat provides maximum comfort by sensing whether your home needs heating or cooling with the Smart Response Learning technology.
If the heating does not start
- Confirm the mode: Check that the display or switch shows Heat, not Cool or Off.
- Check the setpoint: Set the target temperature above the displayed room temperature.
- Check schedule behavior: If your model uses a schedule, see whether it is overriding your target or whether a temporary hold is active.
- Allow the thermostat time to respond: Follow any delay shown on the thermostat or described in its manual. Compressor-protection delays chiefly apply to cooling; do not repeatedly toggle settings to force a start.
- Consult the model manual: If the thermostat still does not call for heat, follow the manual’s troubleshooting steps. Seek qualified HVAC service if the equipment does not respond; changing installer configuration or opening wiring is not needed for a basic mode switch.
Cooling safety note
Honeywell manuals warn against operating cooling when the outdoor temperature is below 50°F (10°C) because the compressor may be damaged. The warning appears in manuals for representative models, including the PRO TH4110B and PRO 1000; follow the warning and instructions in your own model’s manual. Some thermostats also impose a compressor-protection delay before cooling starts.
Quick Recap
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- PRECISE TEMPERATURE CONTROL: Precise temperature control of +/- 0.5 degree Celsius.
- DIGITAL DISPLAY: Easy-to-read digital display.
- SIMPLE TO USE: Simple, soft-touch buttons allow you to select the temperature quickly and easily.
- EASY-ACCESS: Easy-access battery compartment and change battery reminder.
- SET POINT RETAINED: Set point is retained in memory in the event of a power outage.
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