Carrier Programmable Thermostats Instructions and recipes

Programmable Thermostats
Installation, Start-Up, and Operating Instructions
NOTE: Read the entire instruction manual before starting the
installation. SAFETY CONSIDERATIONS
Read and follow manufacturer instructions carefully. Follow all
local electrical codes during installation. All wiring must conform
to local and national electrical codes. Improper wiring or installa-
tion may damage thermostat.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol on the equipment and in the instruction
manual, be alert to the potential for personal injury.
Understand the signal words DANGER, WARNING, and CAU-
TION. These words are used with the safety-alert symbol. DAN-
GER identifies the most serious hazards which will result in severe
personal injury or death. WARNING signifies a hazard which
could result in personal injury or death. CAUTION is used to
identify unsafe practices which would result in minor personal
injury or product and property damage.
INTRODUCTION
Carrier’s 7-day programmable thermostats are wall-mounted, low-
voltage thermostats which maintain room temperature by control-
ling the operation of a heating and air conditioning system.
Separate heating and cooling setpoints, plus auto changeover allow
setback programming for maximum energy savings. All of the
thermostats allow up to 4 time/temperature settings to be pro-
grammed per 24 hr period and store programs for 7 independent
days. Batteries are not required; during a power interruption, the
internal memory stores programs for an unlimited time and the
clock continues to run for at least 72 hrs.
INSTALLATION CONSIDERATIONS
Power
Note that all TSTAT models have no batteries and are not ″power
stealing″. They do require 24VAC (R and C terminals) to be
connected for proper operation. Thermostat will not operate
without these 2 connections.
Models
There are 3 different models. The 9th and 10th letters of the part
number indicate the model. These 2 letters appear on the package
and on the circuit board. Be sure to have the proper thermostat for
the intended application. Models are:
AC - 1-stage cool, 1-stage heat - for AC systems only.
HP - 1-stage cool, 2-stage heat - for either HP or AC with 2-stage
heat.
2S - 2-stage cool, 2-stage heat - for 2-speed AC systems, or
2-stage cool, 3-stage heat - for 2-speed HP systems, or
1-stage cool, 4-stage heat - for 1-speed HP with special
3-stage electric heat.
Use each only for its intended purpose. (See Table 1.)
INSTALLATION
Step 1—Thermostat Location
Thermostat should be mounted:
• Approximately 5 ft (1.5m) from floor.
• Close to or in a frequently used room, preferably on an inside
partitioning wall.
• On a section of wall without pipes or duct work.
Thermostat should NOT be mounted:
• Close to a window, on an outside wall, or next to a door leading
to the outside.
• Exposed to direct light and heat from a lamp, sun, fireplace, or
other temperature-radiating object which may cause a false
reading.
• Close to or in direct airflow from supply registers and return-air
grilles.
• In areas with poor air circulation, such as behind a door or in
an alcove.
Step 2—Set DIP Switches
There are 4 small switches on the back of the circuit board which
must be set by the installer. The ON position is indicated by small
letters on the switch itself. Ignore numbers 1-4 on the switch. The
switch designation (A through D) is on the circuit board next to the
switch. To change a switch position use the corner of a small
screwdriver to slide it between on and off. Make these selections
BEFORE installing the thermostat--it is much easier.
Switch A - Zoning Select (Active on all models)
This switch selects or defeats the 4 cycles per hour limit and a
5-minute compressor timeguard. These timers MUST be enabled
for normal operation and disabled for zoning applications. (In
zoning applications the zone control center performs these timing
functions.)
TO SET:
OFF— for normal operation. This is the factory default.
ON—for zoned installations ONLY.
Switch B - Setback Recovery (Active on all models)
Selects between normal and smart recovery from setback. Normal
recovery changes to the new setpoint at the programmed time.
Smart recovery, which is active in heating mode only, starts earlier
Fig. 1—Carrier Programmable Thermostat
A94134
®
HEIGHT (IN.) WIDTH (IN.) DEPTH (IN.)
4-1/4 7-1/2 1-3/8
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab misc. misc. PC 101 Catalog No. 92-33TS-TA15C Printed in U.S.A. Form TSTAT-4SI Pg 1 4-95 Replaces: TSTAT-1SI

and adjusts the setpoint slowly so that room temperature will arrive
at the programmed temperature at the programmed time.
TO SET:
OFF—for smart recovery. This is the factory default.
ON—for normal recovery.
Switch C - HP/AC Select (Active on HP and 2S models only)
Use to select between AC and HP installations. HP and 2S models
have an extra relay to control the HP reversing valve. When a HP
thermostat is placed in the AC mode, this extra relay is converted
to a second stage heat output. This allows thermostat control of
2-stage furnaces or 2-stage strip heat with AC systems. (AC mode
also uses W rather than Y for first-stage heat.)
TO SET:
OFF—for HP applications. Extra relay controls reversing valve.
This is factory default.
ON—for AC applications. Extra output can be used for 2-stage
heat.
Switch D - Staging Select (Active on 2S models only)
This switch converts a 2-speed heat pump thermostat with 1 stage
of auxiliary heat into a 1-speed heat pump thermostat with 3 stages
of auxiliary heat for comfortable leaving air temperature. It
requires selected heaters with 2:1 ratio element sizes plus an FK4
fan coil. Refer to FK4 fan coil literature for details.
TO SET:
OFF—for normal 2-speed operation. This is factory default.
ON—for special 3-stage heat with FK4 fan coil.
Step 3—Install Thermostat
Before installing thermostat, turn off all power to unit. There
may be more than 1 power disconnect. Electrical shock can
cause personal injury or death.
1. Turn OFF all power to unit.
2. If an existing thermostat is being replaced:
a. Remove existing thermostat from wall.
b. Disconnect wires from existing thermostat, 1 at a time. Be
careful not to allow wires to fall back into the wall.
c. As each wire is disconnected, record wire color and
terminal marking.
d. Discard or recycle old thermostat.
NOTE: Mercury is a hazardous waste and MUST be disposed of
properly.
3. Open thermostat rear door (mounting base) to expose mount-
ing holes. The base can be removed to simplify mounting.
Snap apart carefully at hinge to separate mounting base from
remainder of thermostat.
4. Route thermostat wires through large hole in mounting base.
Allow an extra 10 to 12 in. of wire for connection to terminals.
Remove outer sheath over this entire length for added flex-
ibility.
5. Level mounting base against wall and mark wall through 2
mounting holes.
6. Drill two 3/16-in. mounting holes in wall where marked.
7. Secure mounting base to wall with 2 screws and anchors
provided, making sure all wires extend through mounting
base.
8. Adjust wire length and routing to allow proper closure of
thermostat. Strip each wire end no more than 1/4 in. to prevent
adjacent wires from shorting together. Match and connect
equipment lead wires to the correct terminals of the thermostat
connector. (See Table 1 and Fig. 2 through 14.) Both R and C
must be connected for proper thermostat operation.
Improper wiring or installation may damage the thermostat.
Check to make sure wiring is correct before proceeding with
installation or turning on unit.
9. Push excess wiring into wall. Seal hole in wall to prevent
drafts.
10. Snap hinge back together.
11. Close thermostat door.
12. Turn ON power to unit.
On power up, display shows selected setup mode AC, HP, A2, H2,
or HS for a few seconds depending on model and DIP switch
settings.
Step 4—Set Thermostat Configuration
Configuration options, like DIP switch settings, are intended to be
selected at installation and normally are not modified by the
homeowner. These options are not discussed in the homeowner’s
manual and therefore must be made as part of the installation. A
special procedure allows entry into the configuration mode. The
thermostat will automatically exit this mode if no button is pressed
for 10 seconds. While in configuration mode, 5 option choices can
be made:
1. Fahrenheit or Celsius—Selection.
2. Fan (G) ON with heat (Any W)—Selection.
3. High ambient heat lockout (HP only)—Selection and Value
Adjustment.
4. Clean filter timer—Selection and Value Adjustment.
5. ’Anticipator’—Value Adjustment.
An explanation for each of these and how to enter the configura-
tion mode follows.
To enter the configuration mode:
Press and hold FAN button for approximately 10 sec until room
temperature disappears and display reads "--". You are now in the
configuration mode.
NOTE: If no button is pressed for 10 sec, thermostat will exit
mode and resume normal operation. To re-enter configuration
Table 1—Model Selection and Wiring Diagram Chart
OUTDOOR
UNIT AIR CONDITIONER HEAT PUMP
1 Speed 2 Speed 1 Speed 2 Speed
1-Stage
Furnace Model AC See Fig. 2 Model 2S See Fig. 8 Requires Interface Control or Dual Fuel Thermostat Model 2S See Fig. 11
2-Stage
Furnace Model AC See Fig. 3 Model HP See Fig. 4 Model 2S See Fig. 9 Requires Interface Control or Dual Fuel Thermostat Model 2S See Fig. 12
Fan Coil Model AC
See Fig. 5 Model HP See Fig. 6 Model 2S See Fig. 10 Model HP See Fig. 7 Model 2S See Fig. 13
FK4
Fan Coil Model AC See Fig. 5 Model HP See Fig. 6 Model 2S See Fig. 10 Model 2S See Fig. 14 Model 2S See Fig. 13
2

mode, FAN button must be pressed and held again.
While in Configuration Mode, these selections are available:
Fahrenheit or Celsius—Selection
Select between Fahrenheit or Celsius operation. Factory default is
Fahrenheit.
TO SELECT:
1. Enter configuration mode.
2. Press CHANGE DAY button to display F or C.
3. Use either up or down button to change between F and C.
G OFF or ON with W—Selection
Select whether the G (fan) output is to be OFF or ON when a W
(furnace or strip heat) output is ON. Factory default is OFF.
TO SELECT:
1. Enter configuration mode.
2. Press HOLD button to display OF (off) or ON (on).
3. Use either up or down button to change between OF (off) and
ON (on).
High Ambient Electric Heat Lockout—Selection and Adjustment
Present in HP models only. Outdoor temperature sensor must be
attached. Selection allows lockout of any W (Electric Heat) when
outdoor temperature is above a selected value. Temperatures of 15
to 55°F (or equivalent values in °C) can be selected. Feature can be
enabled or disabled. EMERGENCY HEAT mode disables. Fac-
tory default is OFF (disabled).
TO SELECT:
1. Enter configuration mode.
2. Press COPY PREVIOUS DAY button.
3. Use up and down buttons to move between OF (off), 15, 20,
25, 30, 35, 40, 45, 50, or 55.
Clean Filter Timer—Selection and Adjustment
Select hours of blower operation before CLEAN FILTER icon is
displayed. Timer accumulates total blower hours. Selection can
range from 400 to 3600 hours or can be turned off. Factory default
is 2 (800 hours). Recommended selections are: disposable
filter—400 to 800 hours, media filter—1200 to 1600 hours, or
electronic air cleaner—1600 to 2400 hours of blower operation.
TO SELECT:
1. Enter configuration mode.
2. Press RESET FILTER button to display OF (off) or digits 1
through 9.
3. Use up and down buttons to move between selections. Total
hours equals 400 times the displayed number. OF (off) turns
feature off.
4. During the selection process, the CLEAN FILTER icon will
remain on, even if OF (off) is chosen.
’Anticipator’—Adjustment
This adjustment controls the sensitivity and cycle rate of the
thermostat. Higher numbers decrease the sensitivity and slow the
cycle rate. Lower numbers increase sensitivity and increase cycle
rate. However, a limiting feature will not allow more than 4
equipment cycles per hour, regardless of setting. Values can range
from 1 to 9. Default is 3. This default selection will provide
optimum performance in nearly all installations. Try it first. Do not
change setting unless there is evidence of need to do so.
Unlike conventional anticipators, this setting is not to be deter-
mined by current draw. There is no need to measure, know, or
compensate for current. There is also no ’droop’ with this
thermostat, regardless of ’anticipator’ setting.
This adjustment controls only sensitivity and cycle rate—up to the
maximum of 4 cycles per hour.
TO ADJUST:
1. Enter configuration mode.
2. Press MODE button to display value between 1 and 9. Factory
default is 3.
3. Use up and down buttons to move between values.
Step 5—Hold, Fan, Mode Button Operation
1. Pressing HOLD button disables the time/temperature schedule
and ″holds″the current desired temperature. When active, the
HOLD annunciator is turned on. A second press of the HOLD
button releases the hold feature and turns off the annunciator.
2. Pressing the FAN button alternately selects AUTO or ON fan
operation. Fan annunciator displays the current selection.
3. Pressing the MODE button will select OFF, HEAT, COOL,
and AUTO. Heat pumps also have an EHEAT mode. Mode
annunciator displays the current selection.
4. Operation of other buttons is explained in the Homeowner’s
Guide.
Step 6—Check Thermostat Operation
SELECT HOLD
1. Press HOLD button to select ″hold″feature. This will prevent
the setpoint from changing until the desired time/temperature
schedule is entered.
FAN OPERATION
1. Press FAN button, starting fan operation. Fan annunciator
switches from AUTO to ON.
2. Press FAN button, stopping fan operation. Fan annunciator
switches from ON to AUTO.
HEATING OPERATION
1. Press MODE button until HEAT is displayed under the mode
annunciator.
2. Press up button until display reads 10 degrees above room
temperature. Heating system should begin to operate within 5
minutes.
COOLING OPERATION
1. Press MODE button until COOL is displayed under the mode
annunciator.
2. Press down button until display reads 10 degrees below room
temperature. Cooling system should begin to operate within 5
minutes.
Step 7—Select Desired Operation
1. Press FAN button to select AUTO or ON position. Fan
annunciator displays current selection.
2. Press MODE button to select OFF, HEAT, COOL, AUTO.
Heat pumps will also have an EHEAT mode. Mode annun-
ciator displays current selection.
3. Press up or down buttons to select desired temperature.
4. If daily cycles are to be programmed now, refer to Homeown-
er’s Guide for programming instructions.
5. If thermostat has not been programmed, press HOLD button to
retain desired temperature setting.
NOTE: If HOLD button is not left ON, temperature setting will
be lost until time/temperature program is entered.
Step 8—Checklist
1. Put away tools and instruments, and clean up debris.
2. Review Homeowner’s Guide with owner.
3. Leave literature packet with owner.
3

Fig. 2—Single-Speed Air Conditioner with Single-
Stage Furnace—Model AC Thermostat
A94217
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 1

N/A

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
W
Y
24 VAC COMM.

N/A

N/A

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL AC
THERMOSTAT SINGLE-STAGE FURNACE SINGLE-SPEED AIR CONDITIONER
See note 1
Fig. 3—Single-Speed Air Conditioner with 2-Stage
or Variable-Speed Furnace—Model AC Thermostat
A94218
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 1

N/A

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

N/A

N/A

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL AC
THERMOSTAT
TWO-STAGE OR
VARIABLE-SPEED
FURNACE SINGLE-SPEED
AIR CONDITIONER
See notes 1 and 5
W/W1
Y/Y2
W2
A94273
Fig. 4—Single-Speed Air Conditioner with
2-Stage or Variable-Speed Furnace
—Model HP Thermostat
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 1

HEAT STAGE 2

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

N/A

N/A

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL HP
THERMOSTAT TWO-STAGE OR
VARIABLE-SPEED
FURNACE SINGLE-SPEED
AIR CONDITIONER
See note 2
W/W1
Y/Y2
W2
A94219
Fig. 5—Single-Speed Air Conditioner with Typical
Fan Coil—Model AC Thermostat
(Single-Stage Heat Control)
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 1

N/A

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

N/A

N/A

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL AC
THERMOSTAT TYPICAL FAN COIL SINGLE-SPEED AIR CONDITIONER
See notes 1 and 6
W2
Y/Y2
W3
*
Y1 *
*
*
O
L
E
4

Fig. 6—Single-Speed Air Conditioner with Typical
Fan Coil—Model HP Thermostat
(Dual-Stage Heat Control)
A94274
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 1

HEAT STAGE 2

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

N/A

N/A

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL HP
THERMOSTAT TYPICAL FAN COIL SINGLE-SPEED AIR CONDITIONER
See notes 2 and 6
W2
Y/Y2
W3
*
Y1 *
O
L
E
*
*
Fig. 7—Single-Speed Heat Pump with Typical
Fan Coil—Model HP Thermostat
A94220
24 VAC HOT

FAN

HEAT STAGE 2

COOL/HEAT
STAGE 1

RVS COOLING

N/A
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

RVS HEATING

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
MODEL HP
THERMOSTAT TYPICAL FAN COIL SINGLE-SPEED HEAT PUMP
See notes 3 and 6
W2
Y/Y2
O
*
W3
E
L *
*
Y1 *
R
W2
O
A94221
Fig. 8—Two-Speed Air Conditioner with Single-
Stage Furnace—Model 2S Thermostat
COOL STAGE 1

FAN

HEAT STAGE 1

COOL STAGE 2

N/A

24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM.

N/A

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y2
C
MODEL 2S
THERMOSTAT SINGLE-STAGE FURNACE TWO-SPEED AIR CONDITIONER
See note 2
W
R
Y1
R
G
L
Y
Fig. 9—Two-Speed Air Conditioner with 2-Stage or
Variable-Speed Furnace—Model 2S Thermostat
A94222
COOL STAGE 1

FAN

HEAT STAGE 1

COOL STAGE 2

HEAT STAGE 2

24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM.

N/A

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y2
C
MODEL 2S
THERMOSTAT TWO-STAGE OR VARIABLE-SPEED
FURNACE TWO-SPEED
AIR CONDITIONER
See note 2
R
Y1
R
G
L
W/W1
Y/Y2
W2
5

Fig. 10—Two-Speed Air Conditioner with Typical
Fan Coil—Model 2S Thermostat
A94223
24 VAC HOT

FAN

HEAT STAGE 1

COOL STAGE 2

HEAT STAGE 2

COOL STAGE 1
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

N/A

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y2
C
MODEL 2S
THERMOSTAT TYPICAL FAN COIL TWO-SPEED AIR CONDITIONER
See notes 2 and 6
W2
Y/Y2 *
Y1
E
L*
O*
R
W3
*Y1
L
A94224
Fig. 11—Two-Speed Heat Pump with Single-Stage
Furnace—Model 2S Thermostat
COOL/HEAT
STAGE 1

RVS COOLING

HEAT STAGE 3

COOL/HEAT
STAGE 2

FAN

24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM.

RVS HEATING

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
YY2
C
W2
MODEL 2S
THERMOSTAT SINGLE-STAGE FURNACE TWO-SPEED HEAT PUMP
See note 3
R
Y1
O
R
W3
G
L
W
Fig. 12—Two-Speed Heat Pump with 2-Stage or
Variable-Speed Furnace—Model 2S Thermostat
A94225
COOL/HEAT
STAGE 1

RVS COOLING

HEAT STAGE 3

COOL/HEAT
STAGE 2

FAN

24 VAC HOT R
W/W1
Y/Y2
O/W2
Y1/W2
G
24 VAC COMM.

RVS HEATING

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y2
C
W2
MODEL 2S
THERMOSTAT TWO-STAGE OR VARIABLE-SPEED
FURNACE TWO-SPEED
HEAT PUMP
See notes 3 and 5
R
Y1
O
R
W3
G
L
W/W1
Y/Y2
W2
Fig. 13—Two-Speed Heat Pump with Typical
Fan Coil—Model 2S Thermostat
A94226
24 VAC HOT

FAN

HEAT STAGE 3

COOL/HEAT 
STAGE 2

RVS COOLING

COOL/HEAT 
STAGE 1
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

RVS HEATING

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y2
C
W2
R
O
Y1
W3
L
MODEL 2S
THERMOSTAT TYPICAL FAN COIL TWO-SPEED HEAT PUMP
See notes 3 and 6
W2
Y/Y2
O
*
Y1 *
*
L
E
*
W3
6

Fig. 14—Single-Speed Heat Pump with FK4
Fan Coil and Special 3-Stage Electric Heat
—Model 2S Thermostat
A94275
24 VAC HOT

FAN

HEAT STAGE 2

COOL/HEAT 
STAGE 1

RVS COOLING

HEAT STAGE 3
R
G
W/W1
Y/Y2
O/W2
Y1/W2
R
G
24 VAC COMM.

RVS HEATING

TROUBLE

OUTDOOR

SENSOR

CONNECTION
C
B
L
S1
S2
C
Y
C
R
O
W2
MODEL 2S
THERMOSTAT FK4 FAN COIL SINGLE-SPEED HEAT PUMP
See note 4
W2
Y/Y2
O
W3
L
E
Y1
WIRING DIAGRAM NOTES:
1. Model AC has no connection to its O/W2 or Y1/W2 outputs.
Switch C does nothing. It can only control 1-stage cool and
1-stage heat.
2. Model HP or 2S, when used in air conditioner installations
(Switch C ON), uses O/W2 to control second-stage heat. Refer
to indoor unit instructions for proper setup.
3. Model HP or 2S, when used in heat pump installations (Switch
C OFF), uses O/W2 to control the reversing valve.
4. Special application: Model 2S thermostat with switch C OFF
and switch D ON uses single-speed heat pump, FK4 fan coil
with selected 2:1 size ratio heaters. Provides 3 stages of
auxiliary heat for even heating comfort via W/W1 and
Y1/W2. Refer to FK4 installation instructions.
5. Furnace second-stage is controlled by its internal algorithm.
Refer to furnace instructions for proper setup.
6. Terminals marked with * are not present on all fan coils.
7

OPERATIONAL INFORMATION
Five-minute Compressor Timeguard
This timer prevents the compressor from starting unless it has been off for at least 5 minutes. It can be defeated for 1 cycle by simultaneously
pressing the FAN mode button and the INCREASE TEMPERATURE button.
Fifteen-minute Cycle Timer
This timer prevents the start of a heating or cooling cycle until at least 15 minutes after the last start of the same cycle. Its function is to assure
that equipment is not cycled more than 4 times per hour. This timer is defeated for 1 cycle when the desired temperature is manually changed.
It can also be defeated for 1 cycle by simultaneously pressing the FAN mode button and the INCREASE TEMPERATURE button.
Fifteen-minute Staging Timer
In multistage heating or cooling, this timer prevents any higher stage from turning on until the preceeding stage has been on for 15 minutes.
This timer is defeated if the temperature error is greater than 5 degrees (usually due to a large change in desired temperature).
Two-minute Minimum On Time
In normal operation, when a stage turns on, it will not turn off for a minimum of 2 minutes.
Heat/Cool Setpoints (Desired Temperatures)
A minimum difference of 3 degrees is enforced between heating and cooling desired temperatures. This is done by allowing one setting to
″push″the other, to maintain this difference.
Auto Changeover
When the auto changeover mode is selected, a change from heat to cool (or vice versa) will not occur until an opposite mode demand has existed
for 20 minutes. If the setpoint is changed, the 20 minute requirement is deleted.
Power On Check
When AC power is first applied, all segments of the display are turned on for a few seconds. Following this, the temperature display indicates
the model/configuration via the following 2 digit code:
AC—1-speed air conditioner, HP—1-speed heat pump, A2—2-speed air conditioner, H2—2-speed heat pump, HS—1-speed heat pump with
3-stage auxiliary heat.
Error Codes
E1 - If the thermostat cannot properly read room temperature, the display will indicate E1 and all outputs (except the fan if on) will turn off.
This is to prevent operation of the equipment if the thermostat has failed.
E2 - If the AC line voltage drops below a minimum (brownout) level, all outputs are turned off and the display indicates E2. This condition
will remain for 15 seconds after proper line voltage is restored. If the AC line voltage disappears completely, the display will immediately
go blank.
Energy Savings Icon
This icon is displayed under these conditions:
1-speed HP heating without auxiliary heat.
2-speed HP on LO or HI speed heating without auxiliary heat.
2-speed HP or AC on LO speed cooling.
Smart Recovery
With Smart Recovery selected, the transition out of a heating setback begins a fixed time period before the selected recovery time and gradually
adjusts room temperature so that the desired temperature will be achieved at the selected recovery time. The fixed time period is 1 hr for
furnaces and 1.5 hrs for heat pumps. Thermostat Troubleshooting
SYMPTOM WHAT TO CHECK
No LCD on temperature display Check for 24 VAC between R and C at terminal connections. Both R and C must be connected for proper opera-
tion.
″E2″on temperature display Brownout condition or too low of voltage to thermostat. Double check wiring and check for 24 VAC between R and
C. E2 will clear 15 seconds after proper voltage is restored.
″E1″on temperature display Temperature sensor reading out of range. Check sensor for damage. If recycling power does not clear display,
thermostat should be replaced.
″Clean Filter″on temperature display After the selected number of hours of blower operation ″clean filter″will display on LCD. This is to remind the ho-
meowner to ″check″filter. Press ″reset filter″button to clear display and reset timer to 0.
″Trouble″on temperature display This will indicate a problem with system equipment. 24 VAC is present on the ″L″terminal connection.
″--″on temperature display If the outdoor sensor is open, not connected, or shorted ″--″will be displayed.
Cooling will not come on Select COOL mode. Decrease cooling setpoint to 10 degrees below room temperature. Simultaneously press FAN and INCREASE TEMPERATURE buttons to defeat timers. Check for 24 VAC at Y/Y2 terminal. If present, thermo-
stat is OK and problem is with equipment or wiring. If not present, replace thermostat.
Heating will not come on
Select HEAT mode. Increase heating setpoint to 10 degrees above room temperature. Simultaneously press FAN
and INCREASE TEMPERATURE buttons to defeat timers. Check for 24 VAC at Y/Y2 (with HP) or W/W1 (with
AC) terminal. If present, thermostat is OK and problem is with equipment or wiring. If not present, replace thermo-
stat.
Copyright 1995 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 tstat4si
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1 4
Tab misc. misc. PC 101 Catalog No. 92-33TS-TA15C Printed in U.S.A. Form TSTAT-4SI Pg 8 4-95 Replaces: TSTAT-1SI