Wiring
Power Supply
1
Factory-installed jumper,
2
remove only when installing on 2-transformer system.
Use either O or B terminals for changeover valve.
3
A 24 VAC 500mA common connection is required with this thermostat.
4
Typical 1H/1C system: 1 transformer
4
Typical 1H/1C heat pump system
2
1
4
3
Typical heat only system
2
4
5
Technician Setup Menu
To enter tech setup:
1. Press and hold the + and - buttons for 3 seconds.
2. Press and hold the TECH button for 3 seconds.
3. Configure the installer options as desired using the table below. Use the + or - buttons to
change settings and the lower left and right buttons to move from one step to another.
4. To exit tech setup: press and hold the + and - buttons for 3 seconds, or wait 60 seconds.
Tech Setup Steps
This feature allows the installer to
Room
change the calibration of the room
Temperature
temperature display. For example, if the
thermostat reads 70 degrees and you
Calibration
would like it to read 72 then select +2.
The compressor short cycle delay
protects the compressor from "short
Compressor
cycling". This feature will not allow
Short Cycle
the compressor to be turned on for 5
Delay
minutes after it was last turned off.
The swing setting often called "cycle
rate", "differential", or "anticipation" is
adjustable. A smaller swing setting will
Cooling
cause more frequent cycles and a larger
Swing
swing setting will cause fewer cycles.
The swing setting often called "cycle
rate", "differential", or "anticipation" is
adjustable. A smaller swing setting will
Heating
cause more frequent cycles and a larger
Swing
swing setting will cause fewer cycles.
When set to ON this thermostat
will operate a heat pump system
(default). If set to OFF this
Heat Pump
thermostat will operate a
conventional system, and the next
tech step will not appear.
You can configure the system switch for
the particular application. Heat - Off -
System Set
Cool, Heat - Off, Cool - Off, Heat - Off -
Cool – Auto.Note: Emergency Heat is
available in heat pump mode only.
Swing Setting Tip
Temperature swing, sometimes called differential or cycle rate, can be
customized for this individual application. For most applications choose a swing
7
setting that is as wide as possible without making the occupants uncomfortable.
Typical 1H/1C system: 2 transformers
4
Typical heat only systems w/o fan
4
Typical cool-only sytem
2
1
4
LCD Will Show
Adjustment Options
You can adjust the room
0
temperature display to read
4˚above or below the factory
calibrated reading.
CALIBRATE
Selecting "ON" will not allow
the compressor to be turned
0N
on for 5 minutes after the
last time the compressor was
switched off. Select "OFF" to
remove this delay.
COMP DELAY
The cooling swing setting is
adjustable from 0.2˚ to 2˚. A
swing setting of 0.5˚will begin
cooling at approximately 0.5˚
above the setpoint and stop
approximately 0.5˚ below the
setpoint.
COOL SWING
The heating swing setting is
adjustable from 0.2˚ to 2˚. A
swing setting of 0.5˚will begin
heating at approximately 0.5˚
below the setpoint and begin
approximately 0.5˚ above the
HEAT SWING
setpoint.
ON - Configured to operate
heat pump system.
OFF - Configured to operate
conventional system
See page 5 for terminal
designations.
HEAT PUMP
Use the + or - buttons until the
SYSTEM SET
desired application is flashing.
AUTO = (Auto Changeover)
Off
Em.Heat
AutoCool
Wiring
Replacement Thermostat Wiring
1.
If you are replacing a thermostat, make
note of the terminal connections on the
thermostat that is being replaced. In some
cases the wiring connections will not be
color coded. For example, the green wire
may not be connected to the G terminal.
2.
Loosen the terminal block screws. Insert
wires then retighten terminal block screws.
3.
Place nonflammable insulation into wall
opening to prevent drafts.
4.
This thermostat requires a 24V common
wire to the C terminal.
Installation Tip
Do not overtighten terminal block screws, as this can damage the terminal block.
A damaged terminal block can keep the thermostat from fitting on the subbase
correctly or cause system operation issues.
Wiring Chart
For all systems, the following terminals are wired according to whether you have a
single or dual transformer system as shown:
SINGLE
TRANSFORMER
SYSTEM
DUAL
TRANSFORMER
SYSTEM
*FAILURE TO REMOVE PROVIDED JUMPER ON DUAL TRANSFORMER INSTALLATIONS COULD CAUSE SEVERE DAMAGE TO HVAC SYSTEMS
O Terminal
B Terminal
1
Note: Devices such as a float switch that mechanically break circuits should be installed
so that they break the control wire (Y) not the power (R). Interrupting the power circuit
will shut off power to the thermostat completely and not allow it to operate.
If using in Heat Pump without Auxiliary or Emergency heat application,
please see wiring diagram on previous page.
Technician Setup Menu
Tech Setup Steps
This feature controls the number
Emergency
of stages in Emergency Heat
Heat Stages
mode. It only appears if the
Technician Setup Step for HEAT
(Only displayed if Emergency
PUMP is ON.
Heat is set to ON)
For Dual Fuel applications (Gas/
Dual Fuel
Default
Fossil fuel Auxiliary Heat), turn
Auxiliary for
this setting ON to LOCKOUT the
Heat Pump
Heat Pump (Y) when Auxiliary
O
Heat (W2) is on.
(Only displayed if Heat Pump
is set to ON)
also be used with Electric Auxiliary.
This feature allows the thermostat
to keep multiple stages of heat
Satisfy
energized until setpoint is
Setpoint
satisfied.
ON
This feature allows a delay to occur
Staging
when a second stage is needed.
This allows the previous stage
Delay
extra time to satisfy setpoint.
This feature allows the installer
0.5 ˚F
to select the minimum run
time for the compressor. For
Minimum
example, a setting of 4 will force
Compressor
the compressor to run for at
On Time
least 4 minutes every time the
compressor turns on, regardless
0.5 ˚F
of the room temperature.
This feature allows you to set a
Heating
maximum heat setpoint value. The
Setpoint
setpoint temperature cannot be raised
Limit
above this value.
ON
This feature allows you to set a
minimum cool setpoint value. The
Cooling
setpoint temperature cannot be raised
Setpoint
above this value.
Limit
Heat
Off
Cool
Select F for Fahenheit
temperature read out or select C
F or C
for Celsius read out.
Caution:
Electrical Hazard
Failure to disconnect the power
before beginning to install this
product can cause electrical shock or
equipment damage.
Warning:
All components of the control system
and the thermostat installation must
conform to Class II circuits per the
NEC Code.
Max Torque = 6in-lbs.
RH
RC
24 VAC HOT
JUMPER SHOULD REMAIN
24 VAC Common
INSTALLED
24 VAC Common
24 VAC-Heat
24 VAC-Cool
*REMOVE PROVIDED
*REMOVE PROVIDED
*FROM COOL
JUMPER
JUMPER
TRANSFORMER
Heat pump changeover valve-- Energized during cooling
Heat pump changeover valve-- Energized during heating
LCD Will Show
Adjustment Options
Use the
1
select 1-stage or 2-stage
operation.
OFF will allow Y(1st stage of
OF
Heat) and W2 (Aux Heat) to run
together if called for.
ON Will de-energize Y terminal
If desired- This can
45 seconds after a call for
DUAL FUEL
Auxiliary Heat (W2).
Use the
OF
turn ON or OFF.
SATISFY SP
Use the
OF
select OFF, 5, 10, 15, 30, 45,
60, or 90 minutes.
STG DELAY
You can set the minimum
compressor run time to
"OFF", "3", "4", or "5" minutes.
If 3, 4 or 5 is selected, the
OF
compressor will run for at
least the selected time
before turning off. Use the
and
change the setting.
MIN COMP
Use the + and - buttons to select
90
the maximum heat setpoint.
HEAT LIMIT
Use the + and - buttons to select
the minimum cool setpoint.
44
COOL LIMIT
F for Fahrenheit
FC
o
F
C for Celsius
C
G
Blower / Fan
500mA
500mA
Blower / Fan
6
Default
or
key to
1
OFF
or
key to
OFF
or
key to
OFF
OFF
buttons to
90
44
F
8
Need help?
Do you have a question about the T721i and is the answer not in the manual?
Questions and answers