Operating ManualThis is a legacy product documentsupported by Resideo. It is no
longer manufacturedTH4000 SeriesProgrammable Thermostat
Quick Reference CardGrasp and pull to see basic operating instructions at a glance.This manual covers the following models:TH4110D: For 1 Heat/1 Cool systemsTH4210D: For 2 Heat/1 Cool heat pump systems only (Pull thermostat from wallplate and turn over to find the model number.)
CAUTION: EQUIPMENT DAMAGE HAZARD.To prevent possible compressor damage, do not operate the cooling system when the outdoor temperature is below 10°C (50°F).
Read and save these instructions.Patents pending.Copyright © 2013 Honeywell International Inc. All rights reserved.
About your new thermostat
Your new thermostat has been designed to give you many years of reliable service and easy-to-use, push-button climate control.Features
- Separately programmable weekday/weekend schedules.
- One-touch temp control overrides program schedule at any time.
- Energy-saving settings for maximum cost savings.
- The large, clear, backlit display is easy to read.
- Displays both room temperature and temperature settings.
- Built-in compressor protection.
This thermostat is ready to go!
Your new thermostat is pre-programmed. Just set the time and day. Then check the settings below and change if needed:
- Set time and day (required for proper operation) ………………………… See page 6
- Select system setting: Preset to Off ……………………………………………. See page 7
- Select fan setting: Preset to Auto ………………………………………………… See page 8
- Program schedules: Preset to energy-saving levels (assumes you wake at 6 am, leave at 8 am, return at 6 pm and sleep at 10 pm) …………………………………………………. See pages 11-13
ONE-TOUCH TEMP CONTROL: You can override the program schedule at any time, and manually adjust the temperature (see pages 12-13).
A quick reference to controls
temperature adjustment (see page 11-13)
Fan Switch (see page 8)On: Fan runs continuously.Auto: Fan runs only when the heating or cooling system is on.
- Set: Press to set time/day/ schedule.
- Hold: Press to override programmed temperature control.
- Run: Press to resume program schedule.
System switch (see page 7)
- Cool: Cooling system control.
- Off: All systems off.
- Heat: Heating system control.
- Em Heat: Emergency & Auxiliary Heat control. The compressor is locked out. (Select models only.)
A quick reference to display screen
Set the time and day
Press SET, then adjust the time.
Press SET, then select a current day.
1. Press the SET button, then press 
or 
to set the clock time.2. Press the SET button, then press or to select the day of the week.3. Press RUN to save & exit.Note: If the display flashes Set Clock, the thermostat will follow your settings for the weekday “Wake” time period until you reset the time and day.
System switch
The SYSTEM switch can be set to control your heating or cooling system, depending on the season.
- Cool: Cooling system control.
- Off: All systems are off.
- Heat: Heating system control.
- Em Heat: Emergency & Auxiliary Heat control. The compressor is locked out. (Select models only.)
CAUTION: EQUIPMENT DAMAGE HAZARD. Do not operate cooling system when outdoor temperature is below 10°C (50°F).
Fan switch
Set the FAN switch to Auto or On.In “Auto” mode (the most commonly used setting), the fan runs only when the heating or cooling system is on.If set to “On,” the fan runs continuously. Use this setting for improved air circulation, or for more efficient air cleaning.
Save money by setting program schedules
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Set to the time you awaken and the temperature you want during the morning, until you leave for the day. |
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Set to the time you leave home and the temperature you want while you are away (usually an energy-saving level). |
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Set to the time you return home and the temperature you want during the evening, until bedtime. |
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Set to the time you go to bed and the temperature you wantovernight (usually an energy-saving level). |
Energy-saving settings for maximum cost savings
This thermostat is pre-set with energy-saving program settings. We recommend these settings since they can reduce your heating/cooling expenses. (See next page to adjust times and temperatures of each time period.)
To adjust program schedules
- Press SET until Set Schedule is displayed.
- Press
or to set your weekday Waketime (Mon-Fri), then press SET. - Press or to set the temperature for this time period, then press SET.
- Set time and temperature for the next time period (Leave). Repeat steps 2 and 3 for each weekday time period.
- Press SET to set weekend time periods (SatSun), then press RUN to save & exit.
Note: Make sure the thermostat is set to the system you want to program (Heat or Cool). Note: To cancel an unwanted time period (except Wake), press and hold s + HOLD for 4 seconds while n the Set Schedule mode.
Program schedule override (temporary)
Note: Make sure the thermostat is set to the system you want to control (heat or cool).
Press or to immediately adjust the temperature. This will temporarily override the temperature setting for the current time period.The new temperature will be maintained only until the next programmed time period begins (see page 9). For example, if you want to turn up the heat early in the morning, it will automatically be lowered later, when you leave for the day. To cancel the temporary setting at any time, press RUN. Press HOLD to permanently adjust
Program schedule override (permanent)
Note: Make sure the thermostat is set to the system you want to control (heat or cool).
the temperature. This will override the temperature settings for all time periods.The “Hold” feature turns off the program schedule and allows you to adjust the thermostat manually, as needed.Whatever temperature you set will be maintained 24 hours a day, until you manually change it, or press RUN to cancel “Hold” and resume the program schedule.This feature helps prevent damage to the compressor in your air conditioning or heat pump system.
Adaptive Intelligent Recovery (AIR)
Adaptive Intelligent Recovery eliminates guesswork when setting your schedule. It allows the thermostat to “learn” how long your furnace and air conditioner take to reach the temperature you want.Just set your program schedule to the time you want the house to reach your desired temperature. The thermostat then turns on the heating or cooling at just the right time to reach your scheduled temperature at your scheduled time.For example: Set the Wake time to 6 am and the temperature to 21°. The heat will come on before 6 am, so the temperature is 21° by the time you wake at 6.
Built-in compressor protection
Damage can occur if the compressor is restarted too soon after shutdown. This feature forces the compressor to wait 5 minutes before restarting.During the wait time, the display will flash the message Cool On (or Heat On if you have a heat pump). When the safe wait time has elapsed, the message stops flashing and the compressor turns on.Batteries are optional (for backup power) if the thermostat was wired to run on AC power when installed.
About your new ther
Install fresh batteries when the REPLACE BATT warning begins flashing. The warning flashes about two months before the batteries are depleted. Replace batteries once a year, or before leaving home for more than a month. If batteries are inserted within one minute, the time and day will not have to be reset. All other settings are permanently stored in memory and do not require battery power.Accessories/replacement partsCover plate assembly* ………………………….
In case of difficulty
If you have difficulty with your thermostat, please try the following suggestions. Most problems can be corrected quickly and easily.
| Display is blank | • Check the circuit breaker and reset if necessary.• Make sure the power switch at the heating & cooling system is on.• Make sure the furnace door is closed securely.• Make sure fresh AA alkaline batteries are correctly installed (see page 16). |
| Heating or cooling system does not respond | • Set system switch to Heat (see page 7). Make sure the temperature is set higher than the Inside temperature.• Set system switch to Cool (see page 7). Make sure the temperature is set lower than the Inside temperature.• Wait 5 minutes for the system to respond. |
| Temperaturesettings do not change | Make sure heating and cooling temperatures are set to acceptable ranges:• Heat: 4.5° to 32°C (40° to 90°F).• Cool: 10° to 37°C (50° to 99°F). |
| “Cool On” or“Heat On” isflashing | • Compressor protection feature is engaged. Wait 5 minutes for the system to restart safely, without damage to the compressor (see page 15). |
| “Heat On” is not displayed | • Set the System switch to Heat and set the temperature level above the current room temperature (see page 7). |
| “Cool On” is not
displayed |
• Set the System switch to Cool, and set the temperature level below the current room temperature (see page 7) |
| To restore default settings | Follow these steps to restore default settings (see page 10):1. Press SET 3 times to display “Set Schedule.”2. Press and hold SET and RUN at the same time for 4 seconds.3. Press RUN. |
Customer assistance
Part No. 50002883-001*Use to cover marks left by old thermostats.
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