Honeywell T822D Heating-Cooling Thermostat
Pre-installation checklist
Check package contents
- Thermostat
- Wall anchors & screws (2 each)
Before you begin, make sure you have
- No. 2 Phillips & small pocket screwdrivers
- Hammer
- Level (optional)
- Pencil
- Drill and bit (3/16” for drywall, 7/32” for plaster)
Must be installed by a trained, experienced technician
Read these instructions carefully. Failure to follow these instructions can damage the product or cause a hazardous condition.
CAUTION: ELECTRICAL HAZARD
It can cause electrical shock or equipment damage. Disconnect power before beginning installation.
MERCURY NOTICE
If this product is replacing a control that contains mercury in a sealed tube, do not place the old control in the trash. Contact your local waste management authority for instructions regarding recycling and proper disposal.
Product application
This thermostat provides control of:
- 24 Vac heating systems (T822)
- 750 mV or 12 Vdc heating systems (T827K)
- 24 Vac cooling systems (T822L)
System Types
- Gas or oil
- Warm air, hot water, high-efficiency furnaces, heat pumps, steam, gravity
- Normally opened hot water valves (T822K)
- 2-wire cooling systems (T822L)
- Normally closed hot water valves (T822L)
System Settings
- Heat, Off (select models only)
Specifications
Temperature Range
- 50° to 90°F (10° to 32°C)
Operating Ambient Temperature
- 0° to 120°F (-18° to 49°C)
Operating Relative Humidity
- 5% to 90% (non-condensing)
Dimensions (vertical model)
- 2.88W x 4.75H x 1.5D (inches)
- 73W x 121H x 38D (mm)
Dimensions (horizontal model)
- 4.75W x 2.88H x 1.5D (inches)
- 121W x73H x 38D (mm)
Electrical Ratings
Base installation
Wiring
- Loosen screw terminals, insert bare wires beneath screws, then re-tighten screws.
- Push any excess wire back into the wall opening.
- Plug the wall opening with nonflammable insulation to prevent drafts from affecting thermostat operation.
Terminal Designations
R Heating power. Connect to the secondary side of the heating system transformer.
W Heat relay.
Y Compressor or normally closed hot water valve. **
** T822L only
Wire specifications
Use 18-gauge thermostat wire. Shielded cable is not required.
Set heat anticipator (model T822K only)
Thermostat mounting
Align the slots on the cover with tabs on the sides of the base, then push gently until the cover snaps into place.
Operation
5-year limited warranty
Honeywell warrants this product to be free from defects in the workmanship or materials, under normal use and service, for a period of five (5) years 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,
- return it, with a bill of sale or other dated proof of purchase, to the place from which you purchased it; or
- Call Honeywell Customer Care at 1-800-468-1502.
Customer Care will determine whether the product should be returned to the following address:
Honeywell Return Goods, Dock 4 MN10-3860, 1885 Douglas Dr. N., Golden Valley, MN 55422, or whether a replacement product can be sent to you.
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 that 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 FIVE-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 warranty questions, 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, Toronto, Ontario M1V4Z9.
Need Help?
For assistance with this product, please visit http://yourhome.honeywell.com or call Honeywell Customer Care toll-free at 1-800-468-1502
Automation and Control Solutions
Honeywell International Inc.
1985 Douglas Drive North
Golden Valley, MN 55422
http://yourhome.honeywell.com
For more manuals by Honeywell, visit ManualsLibraryy
Honeywell T822D Heating-Cooling Thermostat- FAQs
Q1. How does the Honeywell T822D thermostat work?
It uses a temperature-sensing device (thermistor) to detect room temperature and send signals to your heating or cooling system to maintain comfort.
Q2. How do I set the temperature manually?
Simply turn the dial on the thermostat to your desired temperature. The setting will stay until you adjust it again.
Q3. What is the best thermostat setting for energy savings?
In summer, set it to about 78°F when at home and higher when away. In winter, 68°F is recommended while home, and 60–65°F when sleeping or out.
Q4. How can I check if my thermostat is working properly?
Turn up the heat setting and listen for the furnace to start, or lower the cooling setting to check if the AC comes on. If there is no response, troubleshoot or replace.
Q5. What are common problems with Honeywell thermostats?
Issues may include incorrect temperature readings, dead batteries, or unresponsive controls due to dust buildup, wiring faults, or sensor failure.
Q6. How do I reset a Honeywell thermostat?
Turn the thermostat to “off,” wait a few seconds, then switch it back on. For some models, holding the “Menu” or reset button may restore factory settings.
Q7. How long does a Honeywell thermostat last?
Most Honeywell thermostats last around 10 years with proper use and maintenance.
Q8. Do Honeywell thermostats need batteries?
Yes, most models require batteries. A “Low Batt” indicator usually appears, giving you about 60 days to replace them.