This is a legacy product document supported by Resideo. It is no longer manufactured
When Cool On is flashing, this means the compressor protection is engaged (see section 1.7).
NOTE: The clock has lost its settings when the time display flashes. If the thermostat is following the programmed schedule, it will use the temperature settings programmed for the Wake period until you readjust the clock.
System switch
Use the System switch to place the system in one of the following modes.
CAUTION: EQUIPMENT DAMAGE HAZARD
Do not use Cooling mode when the outdoor temperature is below 50 °F (10 °C).
Fan switch
Use the Fan switch to select the fan operation.
Temperature setting
Press the up or down button once to display the setpoint temperature.
Press either button more than once to change the setpoint.
The ambient (measured) temperature is normally displayed. To view the setpoint temperature, press either of the temperature adjustment buttons once. The setpoint temperature will appear for five seconds.
Built-in compressor protection
Your thermostat has a feature that helps prevent damage to the compressor of your air conditioning system. Because damage can occur if the compressor is restarted too soon after shutdown, this feature forces the compressor to wait five minutes before restarting.
During the wait time, the message Cool On flashes on the screen.
When the safe wait time has elapsed, the message stops flashing and the compressor turns on.
Using the schedule
Press the Run button to follow the programmed schedule. You can have up to four periods in one day. Each period can be programmed with a different temperature setting.
Wake | Morning temperature |
Leave | Daytime temperature |
Return | Evening temperature |
Sleep | Night temperature |
To program a period, you need to set its start time and its two temperature settings (one when the thermostat is in cooling mode and another one when it is in heating mode). The same period and settings are repeated every day.
For maximum energy savings without sacrificing comfort, you can program the schedule such that the temperature is at an economical level when you sleep or are away during the day and at a comfortable level when you are awake and at home.
Factory settings
Period | Start time | Heat | Cool |
Wake | 6:00 a.m. | 70 °F (21 °C) | 75 °F (24 °C) |
Leave | 8:00 a.m. | 62 °F (16.5 °C) | 83 °F (28.5 °C) |
Return | 6:00 p.m. | 70 °F (21 °C) | 75 °F (24 °C) |
Sleep | 10:00 p.m. | 62 °F (16.5 °C) | 78 °F (25.5 °C) |
To temporarily ignore the programmed schedule, press up or down until the desired temperature is displayed. The word Temporary will appear on the screen and the period display will flash to indicate that the current period has been overridden. The new temperature will be used until the next period begins.
NOTE: Pressing up or down once will display the setpoint temperature. To change the setpoint temperature, press either button more than once. Press the Run button if you wish to cancel the temporary setting before the beginning of the next period.
Permanent override of schedule
To permanently ignore the programmed schedule, press up or down until the desired temperature is displayed. Then, press the Hold button to maintain the new temperature indefinitely. The word Hold will appear on the screen.
Press the Run button if you wish to cancel the override and resume the programmed schedule. The word Hold will disappear and the thermostat will be set to the temperature programmed for the current period.
Set the System switch to Off before removing the batteries. Otherwise, the heating/cooling system could remain activated even when batteries are removed.
Install two fresh AAA batteries when Lo Batt (low batteries) flashes on the screen. The icon appears for 60 days before the batteries are depleted. Replace batteries once a year, or when you will be away for more than a month.
Most settings are stored in non-volatile (permanent) memory. Only the clock must be set if the thermostat was without batteries.
Screen is blank: Ensure two fresh AAA alkaline batteries are correctly installed.
Temperature settings cannot be changed:
Honeywell warrants this product, excluding battery, to be free from defects in the workmanship or materials, under normal use and service, for a period of one (1) year from the date of purchase by the consumer. If at any time during the warranty period the product is determined to be defective or malfunctions, Honeywell shall repair or replace it (at Honeywell’s option).
If the product is defective,
This warranty does not cover removal or reinstallation costs. This warranty shall not apply if it is shown by Honeywell that the defect or malfunction was caused by damage which occurred while the product was in the possession of a consumer.
Honeywell’s sole responsibility shall be to repair or replace the product within the terms stated above. HONEYWELL SHALL NOT BE LIABLE FOR ANY LOSS OR DAMAGE OF ANY KIND, INCLUDING ANY INCIDENTAL OR CONSEQUENTIAL DAMAGES RESULTING, DIRECTLY OR INDIRECTLY, FROM ANY BREACH OF ANY WARRANTY, EXPRESS OR IMPLIED, OR ANY OTHER FAILURE OF THIS PRODUCT. Some states do not allow the exclusion or limitation of incidental or consequential damages, so this limitation may not apply to you.
THIS WARRANTY IS THE ONLY EXPRESS WARRANTY HONEYWELL MAKES ON THIS PRODUCT. THE DURATION OF ANY IMPLIED WARRANTIES, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, IS HEREBY LIMITED TO THE ONE-YEAR DURATION OF THIS WARRANTY. Some states do not allow limitations on how long an implied warranty lasts, so the above limitation may not apply to you.
This warranty gives you specific legal rights, and you may have other rights which vary from state to state.
If you have any questions concerning this warranty, please write Honeywell Customer Relations, 1985 Douglas Dr, Golden Valley, MN 55422 or call 1-800-468-1502. In Canada, write Retail Products ON15-02H, Honeywell Limited/Honeywell Limitée, 35 Dynamic Drive, Scarborough, Ontario M1V4Z9.
Customer Assistance
If you have any questions regarding your thermostat, please go to http://yourhome.honeywell.com, or call Honeywell Customer Care toll-free at 1-800-468-1502.
Download Manual:Honeywell RTH221B Programmable Thermostat Installation Guide
Honeywell Home RTH221B Programmable Thermostat Installation Guide
Johnson Controls T7000e LCD Digital Thermostat Johnson Controls T7000e LCD Digital Thermostat Installation Guide
Honeywell T8635L Microelectronic Communicating Programmable Thermostat Honeywell T8635L Microelectronic Communicating Programmable Thermostat USER’s GUIDE
Hetta HS01RF WIRELESS THERMOSTAT Kit PAIRING INSTRUCTIONS Insert batteries into the Thermostat. Ensure that the…
HEAT-MAT NGT-567-0010 Underfloor Heating Thermostat Menu Introduction The NGT thermostat can switch your underfloor heating…
Honeywell RLV450 PROGRAMMABLE THERMOSTAT READ BEFORE INSTALLING DESCRIPTION * LP appears only for the first…
Honeywell RLV431 Programmable Thermostat Description The RLV431 thermostat can be used to control an electric…