Honeywell TH8321U Touch Screen Programmable Thermostat Installation Guide

: June 17, 2024
: Honeywell

Table of Contents

Honeywell TH8321U Touch Screen Programmable Thermostat
Wallplate installation
Power options
Wiring
Remove the tab and mount thermostat
Special functions
Accessories & replacement parts
Specifications
CONTACT
References
Read User Manual Online (PDF format)
Download This Manual (PDF format)

Honeywell TH8321U Touch Screen Programmable Thermostat

This manual covers the following models

TH8110U: For 1 Heat/1 Cool systems
TH8320U: For up to 3 Heat/2 Cool systems
TH8321U: For up to 3 Heat/2 Cool systems with dehumidification (Pull thermostat from wallplate and turn over to find model number)

System Types

Gas, oil, or electric heat with air conditioning
Warm air, hot water, highefficiency furnaces, heat pumps, steam, gravity
Heat only — two-wire systems, power to open and close zone valves (Series 20), and normally open zone valves
Heat only with a fan
Cool only
750 mV heating systems

This thermostat contains a Lithium battery which may contain Perchlorate material. Perchlorate Material—special handling may apply, See www.dtsc.ca.gov/hazardouswaste/perchlorate.

Wallplate installation

Separate wallplate from thermostat.
Mount the wallplate as shown below.

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
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.

Power options

Wiring

Terminal Designations

Shaded areas below apply only to TH8320/TH8321.

Conventional Terminal Letters

R Heating power. Connect to the secondary side of the heating system transformer.
Rc Cooling power. Connect to the secondary side of the cooling system transformer.
C Common wire from the secondary side of the cooling transformer (if 2 transformers).
W 1st stage heat relay.
W2 2nd stage heat relay.
Y 1st stage compressor contactor.
Y2 2nd stage compressor contactor.
G Fan relay.
S1 Optional outdoor or remote sensor.
S2 Optional outdoor or remote sensor.

Heat Pump Terminal Letters

R Heating power. Connect to the secondary side of the heating system transformer.
Rc Cooling power. Connect to the secondary side of the cooling system transformer.
C Common wire from the secondary side of the cooling system transformer.
Y 1st stage compressor contactor.
Y2 2nd stage compressor contactor.
Aux/E Auxiliary/Emergency heat relay.
G Fan relay.
L Heat pump reset (powered continuously when System is set to Em Heat; system monitor when set to Heat, Cool or Off).
O/B Changeover valve for heat pumps.
S1 Optional outdoor or remote sensor.
S2 Optional outdoor or remote sensor.

Wiring guide—conventional systems

Shaded areas below apply only to TH8320/TH8321.

See [notes] below

[1] Power supply. Provide disconnect means and overload protection as required.
[2] Remove jumper for 2-transformer systems.
[3] Optional 24VAC common connection.
[4] Common connection must come from the cooling transformer.

Wiring guide—heat pump systems

Shaded areas below apply only to TH8320/TH8321.

See [notes] below

[1] Power supply. Provide disconnect means and overload protection as required.
[3] Optional 24VAC common connection.
[5] O/B is set to control as either O or B in the installer setup.
[6] If the L terminal is used, 24VAC common (terminal C) must be connected.
[7] Heat pump reset (powered continuously when the thermostat is set to Em. Heat; system monitors when set to Heat, Cool, or Off).

Remove the tab and mount thermostat

Set date and time

Installer setup

Setup functions Settings & Options (factory default in bold)
Shaded areas below apply only to TH8320/TH8321.

Setup functions Settings & Options (factory default in bold)
Shaded areas below apply only to TH8320/TH8321.

Setup functions Settings & Options (factory default in bold)

0500| Furnace filter

change reminder

| 0 Off

1 10-day run time (about 1 month)

2 30-day run time (about 3 months)

3 60-day run time (about 6 months)

4 90-day run time (about 9 months)

5 120-day run time (about 1 year)

6 365-day run time (about 3 years)

---|---|---
0510| Humidifier pad

change reminder

| 0 Off

1 90 calendar days

2 180 calendar days

3 365 calendar days

0520| UV lamp change reminder| 0 Off

1 365 calendar days

0530| Adaptive Intelligent Recovery™| 1 On ** See page 11

0 Off

0540| Program periods| 4 4 program periods (Wake, Leave, Return, Sleep)

2 2 program periods (Wake, Sleep)

0580| Compressor protection| 5 5 minute compressor off time See page 11 [Other options: 0, 1, 2, 3 or 4-minute off time]
0600| Heat temperature range stop| 90 Max. heat temperature setting is 90°F (32°C) [Other options: 40-89°F (4.5°C to 32°C)]
0610| Cool temperature range stop| 50 Min. cool temperature setting is 50°F (10°C) [Other options: 51-99°F (10.5°C to 37°C)]
0640| Clock format| 12 12-hour time (i.e., “3:30 pm”)**

24 24-hour time (i.e., “15:30”)

0650| Extended fan timer (heat)| 0 Off

90 Fan runs for 90 seconds after the call for heat ends

0660| Extended fan timer (cool)| 0 Off

90 Fan runs for 90 seconds after the call for cooling ends

0670| Keypad lock| 0 Keypad unlocked (fully functional)

1 Partially locked (access to temperature settings only)

2 Fully locked

0680| Heat temperature control| 2 Standard temperature control (recommended)

1 Choose if the room is warmer than the set temperature

3 Choose if the room does not reach the set temperature

0690| Cool temperature control| 2 Standard temperature control (recommended)

1 Choose if the room is cooler than the set temperature

3 Choose if a room does not reach a set temperature

0700| Temperature display offset| 0 Thermostat displays actual room temperature [Other options: -3, -2, -1, 1, 2, 3°F offset (-1.5°C to 1.5°C)
0710| RESET| 0 No reset

1 Reset installer options & program schedule to factory default (only date and time settings are retained)

Installer system test

Shaded areas below apply only to TH8320/TH8321

System test System status

CAUTION: EQUIPMENT DAMAGE HAZARD. Compressor protection is bypassed during testing. To prevent equipment damage, avoid cycling the compressor quickly.

Special functions

Shaded areas below apply only to TH8320/TH8321.

Auto Changeover (Setup Function 0300): When set to Auto, the thermostat automatically selects heating or cooling depending on the indoor temperature. Heat and cool settings must be at least 2 degrees apart. If function 0380 is set to On, the heat and cool settings must be at least 5 degrees apart.
Remote Sensor (Setup Function 0340): If an optional outdoor sensor is installed, the thermostat can display the outside temperature. If an optional remote indoor sensor is installed, the thermostat will display the temperature at the sensor location (the internal sensor in the thermostat is not used).
Adaptive Intelligent Recovery (Setup Function 0530): Allows the thermostat to “learn” how long the furnace and air conditioner take to reach programmed temperature settings, so the temperature is reached at the scheduled time.
Compressor Protection (Setup Function 0580): Forces the compressor to wait a few minutes before restarting, to prevent damage. During this time, the message “Wait” flashes on the display.
Dehumidification control (Setup Function 0380): TH8321 models monitor the indoor humidity level and automatically activate the cooling system to reduce humidity by lowering the temperature by up to 3 degrees below the current cool setting.
Heat Pump Temperature Lockout (with fossil fuel backup): If the thermostat is installed with an optional outdoor sensor, you can select a compressor lockout temperature (Function 0350). When the outdoor temperature is below the lockout temperature, only the auxiliary heat operates. When the outdoor temperature is above the lockout temperature, only the compressor operates.
Heat Pump Temperature Lockouts (with electric heat backup): If the thermostat is installed with an optional outdoor sensor, you can select a compressor lockout temperature (Function 0350) and/or an auxiliary heat lockout temperature (Function 0360). When the outdoor temperature is below the compressor lockout temperature, only the auxiliary heat operates. When the outdoor temperature is above the auxiliary lockout temperature, only the compressor operates. If the outdoor temperature is between the compressor and auxiliary lockout temperatures, both the compressor and auxiliary heat can operate.

Accessories & replacement parts

Please contact your distributor to order replacement parts.
Outdoor temperature sensor………………………….Part Number C7089U1006
Remote indoor temperature sensor……………….Part Number C7189U1005
Cover plate*…………………………………………………….Part Number 32003796-001
(Use to cover marks left by old thermostats.)

Specifications

Temperature Ranges
- Heat: 40° to 90°F (4.5° to 32°C)
- Cool: 50° to 99°F (10° to 37°C)
Operating Ambient Temperature
- 0° to 120°F (-18° to 48.9°C)
Shipping Temperature
- -30° to 150°F (-34° to 66°C)
Operating Relative Humidity
- 5% to 90% (non-condensing)
Physical Dimensions
- 4-9/16” H x 6” W x 1-3/8” D
- 116 mm H x 152 mm W x 35 mm D

Electrical Ratings

Terminal Voltage (50/60Hz) Running Current
W Heating 20-30 Vac 0.02-1.0 A
(Powerpile) 750 mV DC 100 mA DC
W2 Heating 20-30 Vac 0.02-0.6 A
Y Cooling 20-30 Vac 0.02-1.0 A
Y2 Cooling 20-30 Vac 0.02-0.6 A
Aux/E Aux. heat 20-30 Vac 0.02-1.0 A
Emergency heat
O/B Changeover 20-30 Vac 0.02-0.6 A
L Heat pump reset 20-30 Vac 0.02-0.6 A

Need Help?
For assistance with this product please visit http://customer.honeywell.com or call Honeywell Customer Care toll-free at 1-800-468-1502