Installer’s Guide

Thermostat
2 Heat/2 Cool Programmable Thermostat
provides electronic control of 24 Vac heating
and coooling systems

MON THU FRI SUN

DONE

TB7220U TB8220U

Model Number (TB7220U) Used With

BAYSTAT050A T_C/ W_C/ Y_C 036 -120 2-TEC 018 -060
ASYSTAT090A TC_/ WC_/ YC_ 150 -301 2TFB-B 018 -030
X13511212-010 TC_/ WC_/ YC_ 330 - 600 2TGB 018 - 048
X13511217-010 TTA 075 - 240 2TEH 018 -060
THT02551 TWA 075 -240 TUX-C 040 -120C
THT02556 CTA 090 - 180 TDX-C 040 -120C
4TTC 018 -060 TUD-C 040 - 140C
Model Number (TB8220U) 2YCC3 018 - 060 TDD-C 040 - 140C
BAYSTAT052A 4YCC3 036 - 060 GEH_/GEV_ 006 -240
ASYSTAT092A YCZ 036 - 060 GET_ 009 - 036
X13511213-010 2WCC3 018 - 060 GER_ 036 -300
X13511218-010 4WCC3 036 - 060 WPH_ 021 - 057
THT02552 WCZ 036, 060 WPV_ 018 -072
THT02557 2TWA0 030 - 072 EXW_ 240
2TWA3 030 - 060 WPW_ 024 -072
2TWB3 018 - 060 GSS_ 024 - 072
2TTA0 030 - 072 GSW_ 024 -072
2TTA3 030 - 060 GSU_ 018 - 072
2TTB3 018 - 060 GEC_ 006 - 018

October 2006 ACC-SVN61A-EN

 Contents
Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Terminal "A" Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Heat Pump System Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Sensor Wiring for Temperature Averaging . . . . . . . . . . . . . . . . . . . . . . . . 13
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Power the Thermostat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Mount Thermostat to Wallplate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Setting Calendar and Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Installer Setup Numbers, Settings, and Tests . . . . . . . . . . . . . . . . . . . . . 15
Economizer/TOD Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

ACC-SVN61A-EN 4
 Installation
Warnings and Cautions appear at Installation Select Thermostat
appropriate sections throughout this
manual. Read these carefully. 1. Read these instructions carefully. Location
Failure to follow them could Select a location for the thermostat
damage the product or cause a about 5 ft (1.5m) above the floor in an
 WARNING 2.
hazardous condition.
Check ratings given in
area with good air circulation at
average temperature. See Figure 1.
Indicates a potentially hazardous instructions and on the product
situation which, if not avoided, could to ensure the product is suitable
result in death or serious injury. for your application.
3. Installer must be a trained,
 CAUTION experienced service technician.
Indicates a potentially hazardous 4. After installation is complete, YES NO

situation which, if not avoided, may check out product operation as

NO
result in minor or moderate injury. It provided in these instructions.
may also be used to alert against NO 5 FEET
[1.5 METERS]
unsafe practices.

CAUTION  WARNING
Indicates a situation that may result Hazardous Voltage!
in equipment or property-damage- Disconnect all electric power,
only accidents. including remote disconnects before
Figure 1. Select thermostat
servicing. Follow proper lockout/
tagout procedures to ensure the location
Application
power cannot be inadvertently
The Programmable Thermostat energized. Failure to disconnect Do not install the thermostat where it
provides electronic control of 24 Vac power before servicing could result can be affected by:
heating and cooling systems. in death or serious injury. • Drafts or dead spots behind
See Table 1 for a description. Disconnect power supply before doors and in corners.
installation. • Hot or cold air from ducts.
Table 1. Thermostat Description • Radiant heat from sun or
Feature Description
appliances.
Powering Battery only • Concealed pipes and chimneys.
Methods Direct connection to a 24 Vac transformer only
Direct connection to a 24 Vac transformer with battery backup • Unheated (uncooled) areas such
System Types Conventional (up to 2 Heat, 2 Cool stages)
as an outside wall behind the
Heat Pump (up to 3 Heat, 2 Cool stages) thermostat.
Changeover Manual or automatic changeover (selectable)
System Setting Heat-Off-Cool-Auto
Fan Setting Auto-On

Note: If this control is replacing a

control that contains mercury
in a sealed tube, do not place
your old control in the trash.
Dispose of properly. Contact
your local waste
management authority for
instructions regarding
recycling and the proper
disposal of an old control.

© 2005 American Standard Inc. All rights reserved ACC-SVN61A-EN

 Installation

Separate Wallplate from 5. Pull the wires through the wire

Thermostat hole on the wallplate and
position the wallplate over the
1. Separate the wallplate from the wall anchors.
thermostat. See Figure 2.
6. Insert the mounting screws into
the wall anchors and tighten.
WALLPLATE

WIRE HOLE DRILLED

HOLES (2)
WALL
ANCHORS (2)

THERMOSTAT WALLPLATE
M22267

Figure 2. Separate wallplate from MOUNTING

M22268 SCREWS (2)
thermostat
Figure 3. Install wallplate
Install Wallplate
Mount the thermostat horizontally on
the wall:
1. Pull the wires through the wire
hole on the wallplate.
2. Position the wallplate on the wall
with the arrow pointing up. Level
the wallplate for appearance
only.
3. Use a pencil to mark the
mounting holes.
4. Remove the wallplate from the
wall and drill two 3/16 in. holes in
the wall (if drywall) as marked.
For firmer material such as
plaster, drill two 7/32 in. holes.
Tap the wall anchors (provided)
into the drilled holes until flush
with the wall.

6 ACC-SVN61A-EN
 Wiring

Note: IMPORTANT! All wiring must 8. Loosen screw terminals used for
agree with applicable codes, the application. Table 2. Terminal designation
ordinances and regulations. descriptions
9. Insert the wires into the terminal
Note: Use 18 gauge thermostat block and tighten each screw Terminal
wire. Shielded cable is not terminal. Designation Description
required. RC (see Note 1) Power for cooling-
10. Push excess wire back into the connect to secondary
• Sensor wires must have a cable wall opening and restrict wires side of cooling system
separate from the thermostat to the shaded area. See Figure 6. transformer.
control cable. R (see Note 1) Power for heating-
11. Plug the wall opening with
connect to secondary
• Refer to Table 2 for terminal nonflammable insulation to side of heating system
designation descriptions. prevent drafts from affecting the transformer.
thermostat.
• See Fig. 7 through 32 for wiring Y Compressor output.
diagrams for specific equipment C (see Note 2) Common wire from
applications. WALLPLATE
secondary side of
WIRE cooling system
7. Select set of terminal transformer.
identifications that correspond
W Heat relay.
to your system type
(conventional or heat pump). G Fan relay.
W2 Second stage heat relay.
Y2 Second stage cooling.
Screw Terminals O/B (see Note 3) Changeover valve for
heat pumps.

W1 A (see Note 4) Economizer/Time-Of-

C C W2
Day (TOD) output-
G G Y2 Y2 powered via RC terminal
WALL OPENING
Y Y A A (TB7220U), powered via
O/B W S1 S1 SHADED AREA M22266 R terminal (TB8220U)
RC RC S2 S2 Figure 6. Restrict wires to shaded S1 (See Note 5) Optional outdoor or
R R area of wire hole indoor remote sensor.
S2 (See Note 5) Optional outdoor or
Conventional indoor remote sensor.
L (TB8220U only) Powers red LED behind
Heat Pump plastic in upper right
corner of the thermostat
Figure 4. TB7220U Terminal
identifications for system type 1. When used in a single-transformer system,
leave metal jumper wire in place between
RC and R. If used on a two-transformer
system, remove metal jumper wire between
RC and R.
2. Common wire is optional when thermostat is
Heat Pump used with batteries. When using separate
transformers for heating and cooling, the
Conventional common must come from the cooling
transformer.
3. If thermostat is configured for a heat pump
in the Installer Setup, configure changeover
Y2 Y2 RC RC valve for cool (factory setting) or heat (B).
L L R R 4. Reference economizer literature for wiring
A O/B details. When set for economizer operation,
A W the A terminal provides the occupancy
W1 W2 Y Y signal. (Power indicates occupied.)
S1 S1 G G 5. Sensor wires must have a cable separate
from the thermostat control cable.
S2 S2 C C

Screw Terminals
Figure 5. TB8220U Terminal
identifications for system type

ACC-SVN61A-EN 7
 Wiring

Terminal "A" Wiring

Table 4. TB8220U Wiring diagrams
Details for Economizers
Wiring
• Wire the A terminal to the W7212 Wallplate Diagram
"N" terminal, or the W7459 "TR" System Type Terminal ID Figure
terminal. Standard Heat/ Conventional 18, 19
Cool
• When using dual transformers at
the thermostat, the cooling Heat Only Conventional 20
transformer must power the Heat Only with Conventional 21
economizer. Fan
Cool only Conventional 22
• The A signal is powered from the
RC terminal and energizes the Standard Conventional 23, 24
economizer to signal occupied Multistage up to 2
Heat/2 Cool
status and drive the damper to
the set minimum position. Heat Pump (No Heat Pump 25, 26
Auxiliary Heat)
Heat Pump (with Heat Pump 27, 28
Table 3. TB7220U Wiring diagrams Auxiliary Heat)
Wiring Multiple T7770A — 29, 30,
Wallplate Diagram Sensors 31
System Type Terminal ID Figure
Multiple C7189U — 32
Standard Heat/ Conventional 7,8 Sensors
Cool
Heat Only Conventional 9
Heat Only with Conventional 10
Fan
Cool only Conventional 11
Standard Conventional 12, 13
Multistage up to 2
Heat/2 Cool
Heat Pump (No Heat Pump 14, 15
Auxiliary Heat)
Heat Pump (with Heat Pump 16, 17
Auxiliary Heat)
Multiple T7770A — 29, 30,
Sensors 31
Multiple C7189U — 32
Sensors

8 ACC-SVN61A-EN
 Wiring
TB7220U

1 C 3 W2
L1
G Y2 1
C 3
(HOT)
Y A L1 W2
24 VAC W S1 (HOT) G Y2
L2 RC S2 L2 24 VAC Y A
2 R W S1
RC S2
HEAT RELAY 2 R
COMPRESSOR CONTACTOR OUTDOOR/INDOOR
TEMPERATURE
FAN RELAY SENSOR OUTDOOR/INDOOR
HEAT RELAY
TEMPERATURE
SENSOR
ECONOMIZER ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

PROTECTION AS REQUIRED.
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
2 FACTORY INSTALLED JUMPER.
PROTECTION AS REQUIRED.
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. M23011 2 FACTORY INSTALLED JUMPER.
Figure 7. Typical wiring of single transformer 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION IS
1H/1C system (TB7220U). OPTIONAL. M23013

Figure 9. Typical hookup heat-only system

(TB7220U).

L1
1 C 3 W2
(HOT) G Y2
Y A
24 VAC
W S1
1 C 3 W2
L1
L2
RC S2 (HOT) G Y2
COOLING 2 Y A
TRANSFORMER R
24 VAC W S1
L2 RC S2
2 R
FAN RELAY
OUTDOOR/INDOOR
1
TEMPERATURE
L1 COMPRESSOR CONTACTOR
SENSOR
(HOT)
HEAT RELAY
24 VAC ECONOMIZER
HEAT RELAY OUTDOOR/INDOOR
L2 FAN RELAY TEMPERATURE
HEATING SENSOR
TRANSFORMER ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

PROTECTION AS REQUIRED. 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2 REMOVE FACTORY INSTALLED JUMPER.
2 FACTORY INSTALLED JUMPER.
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. WHEN USED, THE COMMON MUST CONNECT 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
TO THE COOLING TRANSFORMER SECONDARY. M23012
IS OPTIONAL. M23014
Figure 8. Typical hook-up of dual transformer 1H/1C Figure 10. Typical hook-up heat-only system with fan
system (TB7220U). (TB7220U).

ACC-SVN61A-EN 9
 Wiring
TB7220U

C 3 W2
1 C 3 W2 1
L1 L1 G Y2
(HOT) G Y2 (HOT)
Y A
Y A S1
24 VAC W
24 VAC W S1 L2 RC S2
L2 RC S2 COOLING 2
TRANSFORMER R
2 R
FAN RELAY
OUTDOOR/INDOOR
TEMPERATURE
COMPRESSOR CONTACTOR OUTDOOR/INDOOR
1 COOL RELAY 1 COOL RELAY 2 SENSOR
TEMPERATURE
L1
FAN RELAY SENSOR (HOT) HEAT RELAY 2
HEAT RELAY 1
24 VAC ECONOMIZER
ECONOMIZER
L2
HEATING
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD TRANSFORMER
PROTECTION AS REQUIRED.
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
2 FACTORY INSTALLED JUMPER. OVERLOAD PROTECTION AS REQUIRED.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION 2 REMOVE FACTORY INSTALLED JUMPER.
IS OPTIONAL. M23015
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
Figure 11. Typical hook-up cool-only system IS OPTIONAL. WHEN USED, THE COMMON MUST CONNECT
TO THE COOLING TRANSFORMER SECONDARY. M23017
(TB7220U).
Figure 13. Typical hook-up of dual transformer
multistage system (up to 2H/2C) (TB7220U).

1 C 3
L1
W2
Y2
Heat Pump System Wiring
(HOT) G
Y A
24 VAC W S1
L1
L2 RC S2 (HOT)
2 R
3
24 VAC C W1
OUTDOOR/INDOOR L2 G Y2
COOL RELAY 1 COOL RELAY 2 TEMPERATURE
SENSOR 1 Y A
HEAT RELAY 2 4 O/B S1
FAN RELAY
RC S2
HEAT RELAY 1 ECONOMIZER 2
R

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND CHANGEOVER VALVE OUTDOOR/INDOOR

OVERLOAD PROTECTION AS REQUIRED. TEMPERATURE
COMPRESSOR CONTACTOR 5
SENSOR
2 FACTORY INSTALLED JUMPER.
FAN RELAY
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
M23016
IS OPTIONAL. ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

Figure 12. Typical hook-up of single transformer PROTECTION AS REQUIRED.
multistage system (up to 2H/C) (TB7220U).
2 FACTORY INSTALLED JUMPER.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION

IS OPTIONAL.

4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"

IN THE INSTALLER SETUP.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.

WIRES MUST HAVE A CABLE SEPARATE FROM THE
THERMOSTAT CABLE. M23018

Figure 14. Typical hook-up of single-stage heat pump

with no auxiliary heat (1H/1C) (TB7220U).

10 ACC-SVN61A-EN
 Wiring
TB7220U

L1 L1
(HOT) (HOT)
3 3
24 VAC C W1 24 VAC C W1
L2 G Y2 L2 G Y2
1 1 Y A
Y A
4 O/B S1 4 O/B S1
RC S2
RC S2 2
2 R
R

CHANGEOVER VALVE OUTDOOR/INDOOR

FAN RELAY OUTDOOR/INDOOR TEMPERATURE
TEMPERATURE COMPRESSOR 1 5
SENSOR
SENSOR 5
FAN RELAY
CHANGEOVER VALVE AUXILIARY HEAT RELAY
ECONOMIZER
COMPRESSOR 1 COMPRESSOR 2 COMPRESSOR 2
ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED. PROTECTION AS REQUIRED.

2 FACTORY INSTALLED JUMPER. 2 FACTORY INSTALLED JUMPER.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. IS OPTIONAL.

4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B" 4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"
IN THE INSTALLER SETUP. IN THE INSTALLER SETUP.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.
WIRES MUST HAVE A CABLE SEPARATE FROM THE M23021
WIRES MUST HAVE A CABLE SEPARATE FROM THE THERMOSTAT CABLE.
THERMOSTAT CABLE. M23019
Figure 17. Typical hook-up of multi-stage heat
Figure 15. Typical hook-up of multistage heat
pump with auxiliary heat (3H/2C) (TB7220U).
pump with no auxiliary heat (2H/2C) (TB7220U).

L1
(HOT)
3
24 VAC C W1
L2 G Y2
1 Y A
4 O/B S1
RC S2
2
R

CHANGEOVER VALVE OUTDOOR/INDOOR

TEMPERATURE
COMPRESSOR CONTACTOR 5
SENSOR
FAN RELAY

ECONOMIZER AUXILIARY HEAT RELAY

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

PROTECTION AS REQUIRED.

2 FACTORY INSTALLED JUMPER.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION

IS OPTIONAL.

4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"

IN THE INSTALLER SETUP.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.

WIRES MUST HAVE A CABLE SEPARATE FROM THE M23020
THERMOSTAT CABLE.

Figure 16. Typical hook-up of single-stage heat pump

with auxiliary heat (1H/1C) (TB7220U).

ACC-SVN61A-EN 11
 Wiring
TB8220U

Y2 RC 1 Y2 RC 2 1
2
L R L1 L R L1
(HOT) A W (HOT)
A W
24 VAC L2
W2 Y 24 VAC W2 Y
S1 G L2 S1 G
S2 C S2 C
3 3

FAN RELAY OUTDOOR/INDOOR

HEAT RELAY
OUTDOOR/INDOOR TEMPERATURE
TEMPERATURE COMPRESSOR CONTACTOR SENSOR
SENSOR ECONOMIZER
HEAT RELAY

ECONOMIZER 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

PROTECTION AS REQUIRED.
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD 2 FACTORY INSTALLED JUMPER.
PROTECTION AS REQUIRED.
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION IS
2 FACTORY INSTALLED JUMPER. OPTIONAL. M22783A

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION Figure 20. Typical hook-up of a heat-only system
IS OPTIONAL. M22781A
(TB8220U).
Figure 18. Typical wiring of single transformer
1H/1C system (TB8220U).
Y2 RC 2 1
L R L1
A W (HOT)

Y2 RC W2 Y 24 VAC
2 1
L R S1 G L2
L1
A W (HOT) S2 C
W2 Y 24 VAC
3
S1 G L2
S2 C FAN RELAY
3 OUTDOOR/INDOOR
TEMPERATURE HEAT RELAY
SENSOR
FAN RELAY ECONOMIZER
OUTDOOR/INDOOR
TEMPERATURE 1 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
COMPRESSOR CONTACTOR
SENSOR PROTECTION AS REQUIRED.
L1
(HOT)
HEAT RELAY 2
ECONOMIZER 24 VAC FACTORY INSTALLED JUMPER.

L2 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION

IS OPTIONAL. M22784A
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED. Figure 21. Typical hook-up of a heat-only system
2 REMOVE FACTORY INSTALLED JUMPER. with fan (TB8220U).
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. WHEN USED, THE COMMON MUST CONNECT
TO THE COOLING TRANSFORMER SECONDARY. M22782A

Figure 19. Typical wiring of dual transformer 1H/

1C system (TB8220U).

12 ACC-SVN61A-EN
 Wiring
TB8220U

Y2 RC 1 Y2 RC 2
2 1
L R L R
L1 L1
(HOT) A W (HOT)
A W
24 VAC W2 Y 24 VAC
W2 Y S1 G L2
S1 G L2
S2 C
S2 C
3
3 OUTDOOR/INDOOR
TEMPERATURE FAN RELAY
OUTDOOR/INDOOR SENSOR
TEMPERATURE FAN RELAY
1
SENSOR COOL RELAY 2 COOL RELAY 1
HEAT RELAY 2 L1
COMPRESSOR CONTACTOR (HOT)
ECONOMIZER HEAT RELAY 1 24 VAC
ECONOMIZER
L2

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
PROTECTION AS REQUIRED. OVERLOAD PROTECTION AS REQUIRED.

2 REMOVE FACTORY INSTALLED JUMPER.

2 FACTORY INSTALLED JUMPER.
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION IS OPTIONAL. WHEN USED, THE COMMON MUST CONNECT
IS OPTIONAL. M22785A TO THE COOLING TRANSFORMER SECONDARY. M22787A

Figure 22. Typical hook-up of a cool-only system Figure 24. Typical hook-up of a dual transformer
(TB8220U). multistage system (up to 2H/2C) (TB8220U).

Heat Pump System Wiring

Y2 RC 2 1
L R
L1 L1
A W (HOT) (HOT)
W2 Y 24 VAC Y2 RC 24 VAC
2
S1 G L2 L R L2
S2 C A O/B 4 1
W1 Y
3
S1 G
OUTDOOR/INDOOR S2 C
FAN RELAY 3
TEMPERATURE
SENSOR
OUTDOOR/INDOOR FAN RELAY
COOL RELAY 2 COOL RELAY 1
HEAT RELAY 2 TEMPERATURE
5 COMPRESSOR CONTACTOR
SENSOR
ECONOMIZER HEAT RELAY 1
CHANGEOVER VALVE
ECONOMIZER
1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND
OVERLOAD PROTECTION AS REQUIRED. 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED.
2 FACTORY INSTALLED JUMPER.
2 FACTORY INSTALLED JUMPER.
3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. M22786A 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL.
Figure 23. Typical hook-up of a single
4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"
transformer multistage system (up to 2H/2C) IN THE INSTALLER SETUP.

(TB8220U). 5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.

AVAILABLE ON SELECT MODELS. WIRES MUST HAVE A
CABLE SEPARATE FROM THE THERMOSTAT CABLE. M22788A

Figure 25. Typical hook-up of single stage heat

pump with no auxiliary heat (TB8220U).

ACC-SVN61A-EN 13
 Wiring
TB8220U

L1 L1
(HOT) (HOT)
Y2 2 RC 24 VAC Y2 2 RC 24 VAC
L R L2 L R L2
A O/B 4 1 A O/B 4 1
W1 Y W1 Y
S1 G S1 G
S2 C S2 C
3 3

OUTDOOR/INDOOR FAN RELAY

OUTDOOR/INDOOR FAN RELAY
TEMPERATURE TEMPERATURE
5 5 COMPRESSOR 1
SENSOR SENSOR
CHANGEOVER VALVE CHANGEOVER VALVE
AUXILIARY HEAT RELAY
ECONOMIZER
COMPRESSOR 2 COMPRESSOR 1 COMPRESSOR 2
ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD 1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD
PROTECTION AS REQUIRED. PROTECTION AS REQUIRED.

2 FACTORY INSTALLED JUMPER. 2 FACTORY INSTALLED JUMPER.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION 3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION
IS OPTIONAL. IS OPTIONAL.

4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B" 4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"
IN THE INSTALLER SETUP. IN THE INSTALLER SETUP.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR. 5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.
AVAILABLE ON SELECT MODELS. WIRES MUST HAVE A AVAILABLE ON SELECT MODELS. WIRES MUST HAVE A
CABLE SEPARATE FROM THE THERMOSTAT CABLE. M22789A CABLE SEPARATE FROM THE THERMOSTAT CABLE. M22791A

Figure 26. Typical hook-up of multistage heat Figure 28. Typical hook-up of multistage heat
pump with no auxiliary heat (2H/2C) (TB8220U). pump with auxiliary heat (3H/2C) (TB8220U).

L1
(HOT)
Y2 2 RC 24 VAC
L R L2
A O/B 4 1
W1 Y
S1 G
S2 C 3

OUTDOOR/INDOOR FAN RELAY

TEMPERATURE COMPRESSOR CONTACTOR
5
SENSOR
CHANGEOVER VALVE
AUXILIARY HEAT RELAY ECONOMIZER

1 POWER SUPPLY. PROVIDE DISCONNECT MEANS AND OVERLOAD

PROTECTION AS REQUIRED.

2 FACTORY INSTALLED JUMPER.

3 WHEN USING BATTERIES, THE 24V COMMON CONNECTION

IS OPTIONAL.

4 "O/B" TERMINAL SET TO CONTROL AS EITHER "O" OR "B"

IN THE INSTALLER SETUP.

5 OPTIONAL OUTDOOR OR INDOOR REMOTE SENSOR.

AVAILABLE ON SELECT MODELS. WIRES MUST HAVE A
CABLE SEPARATE FROM THE THERMOSTAT CABLE. M22790A

Figure 27. Typical hook-up of single stage heat

pump with auxiliary heat (2H/1C) (TB8220U).

14 ACC-SVN61A-EN
 Wiring
Sensor Wiring for Temperature Averaging

SUBBASE SUBBASE
S1 S2
S1 S2

T7770A10XX
T7770A T7770A
T T T4 T3
T T T T

1
T7770A30XX
T7770A10XX

T7770A T7770A T T

T T T T

1 THE T7770A3002 IS A 10K OHM SENSOR. M22934

M22831
Figure 31. Wiring two T7770A10XX (20K
Figure 29. Wiring four T7770A10XX (20K ohm) ohm) sensors and one T7770A30XX (10K ohm)
sensors sensor to provide a temperature averaging
network.

SUBBASE
S1 S2 SUBBASE
S1 S2

T4 T3 T4 T3 1 C7189 C7189

1 1
T7770A30XX T7770A30XX C7189 C7189

1 THE T7770A3002 IS A 10K OHM SENSOR.

M22933

Figure 30. Wiring two T7770A30XX (10K ohm)

sensors to provide a temperature averaging 1 WIRES MUST HAVE A CABLE SEPARATE
network. FROM THE THERMOSTAT CABLE.
M23027
Figure 32. Wiring four C7189U (10K ohm)
sensors to provide a temperature averaging
network.

ACC-SVN61A-EN 15
 Operation

Power the Thermostat Memory Backup Battery

You can choose from three methods The thermostat also contains a
to power the thermostat: CR2032 battery used for maintaining
schedule, date, and time. This
• Batteries only. battery will maintain settings for up
• 24 Vac direct connection only. to ten years. This battery should only
be replaced by a certified
• 24 Vac direct connection with professional.
battery backup.
Note: Important! The tab noted in
Wiring 24 Vac Common Figure 33 must be removed
before the battery will
• Single-Transformer System— activate.
Connect the common side of the
REMOVE
transformer to the C screw TAB
terminal of the thermostat
REMOVE DURING
INSTALLATION

wallplate. Leave the metal

jumper wire in place between
RC and R.
• Two-Transformer System—
Connect the common side of the
REMOVE DURING

cooling transformer to the C

INSTALLATION

screw terminal of the thermostat

wallplate. Remove the metal
M22260
jumper wire between RC and R.
Figure 33. Remove tab labeled
Installing Batteries REMOVE from thermostat back.

1. Remove wall plate from back of

thermostat.
Mount Thermostat to
2. Locate battery clips on back of
Wallplate
thermostat. Align the terminal screw blocks with
the pins on the back of the
3. Observing proper polarity,
thermostat.
install two AA alkaline batteries
(TB7220U), or three AAA Push the thermostat straight onto
alkaline batteries (TB8220U). the wallplate until it snaps into place.
(Batteries not provided). It is Figure 34.
recommended that these
batteries be replaced once a year
to ensure proper backup and to
prevent damage due to leakage.

Figure 34. Mount thermostat to

wallplate.

16 ACC-SVN61A-EN
 Operation

Setting Calendar and Setting Date/Time after 3. Hold keys for approximately five
thermostat is already seconds, until the screen
Time changes.
functioning
This thermostat is designed to 4. When the display changes,
automatically keep current time and Use the installer setup to set year,
release the SYSTEM and DONE
day in memory for up to 10 years month, and day. See the Installer
keys.
once the calendar is set. There are Setup Menu, Table 5.
two ways to set the calendar and 5. The setup numbe ris displayed to
the lower left of the screen, with
time for this thermostat: Installer Setup and Tests the current setting to the right.
Setting Date/Time when Configure Installer Setup 6. Refer to Table 5 for Installer
thermostat is first powered Setup numbers and settings.
(TB7220U)
When the thermostat is first 7. Press DONE to exit installer
1. Press and release the SYSTEM setup and return to main screen.
powered, the display is ready to set and FAN keys.
the calendar and time. The
thermostat proceeds through a 2. Press SYSTEM and DONE keys Configure Installer Setup
sequence of setup screens. simultaneously. (TB8220U)
See Figure 35 and Figure 36.
1. Press and release the SYSTEM
and key.
Up and down buttons 2. There will be five blank touch
changes month, day,
Year Day year and time keys between the DONE and
Month CANCEL keys.
3. Press and hold the second and
fourth blank keys until the
display changes, then release the
keys.
4. The setup number is displayed to
the lower left of the screen, with
Go back button
Done button the current setting to the right.
goes back to the
advances to time setting
last setting Next button
screen and home screen 5. Refer to Table 5 for installer
advance to next setting
setup numbers and settings.
Figure 35. TB7220U Setting calendar and time
during initial powerup. 6. Press DONE to exit installer
setup and return to main screen.
Set current day
Set month Installer System Tests
Use the Installer System Test section
MON TUE WED THU FRI SUN MON TUE WED THU FRI SUN
to test the heating, cooling and fan.
OK TO PICK MULTIPLE DAYS SCREEN LOCKED
CHANGE FILTER UV LAMP HUMIDIFIER PAD Refer to the latter portion of Table 5.

PM
CAUTION
Equipment Damage Hazard!
DONE DONE

Minimum compressor off time is

bypassed during Installer System
Test. Avoid cycling compressor
Use arrows to set year and time quickly.
Figure 36. TB8220U Setting calendar and time
Note: IMPORTANT! Use Installer
during initial powerup. System Test to test heating,
cooling and fan. The setting
chosen for System Type
(Installer Setup Number 0170)
can prevent some System
Test Numbers from
appearing.

ACC-SVN61A-EN 17
 Operation

Table 5. Installer setup menu

Installer
Setup Installer Setup Default
Number Name Setting All Settings Notes
0120 Date (Year Upper) 20 20—20xx Available year range: 2001 - 2178
21—21xx
0130 Date (Year Lower) 04 00-99 Available year range: 2001 - 2178
0140 Date (Month) 6 1-12
0150 Date (Day) 15 1-31 (Month Dependent)
0160 Schedule Options 4 0—Non-Programmable
4—Programmable
0170 System Selection 8 1—1H/1C Conv
2—1H/1C HP
3—1H w/o fan
4—1H with fan
6—1C
7—2H/1C HP
8—2H/2C Conv
9—2H/1C Conv
10—1H/2C Conv
11—2H/2C HP
12—3H/2C HP
0175 TOD/Economizer 0 0—Unused Economizer energizes A during a call for cool.
output (terminal A) 1—TOD TOD energizes A during Occupied period, and
2—Economizer deenergizes A during Unoccupied.
0180 Heat Fan Operation 0 0—System controls fan Only shown for conventional system with heat stages
(TB7220U) 1—Thermostat controls (ISU 0170) and fan capability selected.
fan (ON during call for If heat pump is selected, fan always operates with
heat) Thermostat control.
The only thing that allows the fan to turn off during
occupied periods is a manual override of the fan from On
to Auto.
0180 Heat Fan Operation 0 0—Fossil Only shown for conventional system with heat stages
(TB8220U) 1—Electric and fan capability selected.
If heat pump is selected, fan defaults to electric.
0185 Pre-occupancy 0 0—no duration Only shown if thermostat is programmable (ISU 0160).
Purge Duration 1—one hour Pre-occupancy purge enabled by nonzero duration (and
2—two hours sends economizer to minimum position).
3—three hours
0190 Reversing Valve 0 0—O (O/B On Cool) Only shown with heat pump system selected.
O/B 1—B (O/B On Heat)
0220 Cycles Per Hour 3 1-6 Only shown for system with cool stages (ISU 0170).
(CPH) for first Selection in this stage changes second stage cool default
stage compressor CPH.
0230 CPH for second 3 1-6 Only shown for system with two stages of cool (ISU
stage compressor 0170).
0240 CPH for first stage 5 1-12 Only shown for conventional system with heat stages
conventional heat (ISU 0170).
Selection in this stage changes default CPH of second
stage heat.
0250 CPH for second 9 1-12 Only shown for conventional system with at least two
stage conventional stages conventional heat or 2H/1C heat pump (ISU
heat 0170).
0260 CPH for third Stage 9 1-12 Only shown for 3H/2C heat pump system (ISU 0170).
Heat
0270 CPH for Auxiliary 9 1-12 Only shown for multi-stage heat pump system with more
Heat heat than cool stages (ISU 0170).
0280 Continuous 0 0—No Always shown. If AC power not present the option is
Backlight 1—Yes overridden and normal backlight operation occurs.
0300 Changeover 1 0—Manual Only shown for system with both heat and cool stages
1—Auto (ISU 0170).

18 ACC-SVN61A-EN
 Operation

Table 5. Installer setup menu (continued)

Installer
Setup Installer Setup Default
Number Name Setting All Settings Notes
0310 Deadband 3°F 2 (1.5)—2°F (1.5°C) Only shown for Auto Changeover system (ISU 0300).
(2°C) 3 (2.0)—3°F (2.0°C)
4 (2.5)—4°F (2.5°C)
5 (3.0)—5°F (3.0°C)
6 (3.5)—6°F (3.5°C)
7 (4.0)—7°F (4.0°C)
8 (4.5)—8°F (4.5°C)
9 (5.0)—9°F (5.0°C)
0320 Temperature 0 0—°F
Indication Scale 1—°C
0330 Daylight Saving 1 0—Disabled
1—Enabled (US)
0340 Remote 0 0—None Averaging would not include on-board sensor. It is
Temperature 1—Outdoor for Display accomplished by series/parallel combinations.
Sensor 2—Outdoor for Control 2 applies only to Heat Pump applications (allowing
3—Remote 10K Indoor compressor lockout while displaying temperature).
4—Remote 20K Indoor
0350 Heat Pump 0 0—None Only shown for heat pump systems with more heat
Compressor 15(-9.5)—15°F(-9.5°C) stages than cool (ISU 0170) and remote outdoor control
Lockout 20(-6.5)—20°F(-6.5°C) sensor (ISU 0340 is 2).
25(-4.0)—25°F(-4.0°C) Must enforce a dead band between this and Auxiliary
30(-1.0)—30°F(-1.0°C) Lockout.
35(1.5)—35°F(1.5°C)
40(4.5)—40°F(4.5°C)
45(7.0)—45°F(7.0°C)
0360 Heat Pump 0 0—None Only shown for heat pump systems with more heat
Auxiliary Lockout 40(4.5)—40°F(4.5°C) stages than cool (ISU 0170) and remote outdoor control
45(7.0)—45°F(7.0°C) sensor (ISU 0340 at 2).
50(10.0)—50°F(10.0°C) Must enforce a dead band between this and Heat Pump
55(13.0)—55°F(13.0°C) Compressor Lockout.
60(15.5)—60°F(15.5°C)
0535 Temporary 3 0—no duration 0 means no limit.
Occupied Duration 1—one hour
Limit 2—two hours
3—three hours
4—four hours
0540 Number of Periods 4 2—2 Periods Does not appear if Non-programmable is chosen (ISU
4—4 Periods 0160).
Applies to all days of the week.
0580 Minimum 5 0—Off Only shown if system has cool stages (ISU 0170).
Compressor Off 2—2 minutes
Time 3—3 minutes
4—4 minutes
5—5 minutes
0600 Heat Temperature 90 40 to 90°F (4 to 32°C) Only shown if system has heat stages (ISU 0170).
Range Stops
0610 Cool Temperature 50 50 to 99°F (10 to 37°C) Only shown if system has cool stages (ISU 0170).
Range Stops
0640 Clock Format 12 12—12 Hour
24—24 Hour
0650 Extended Fan-on 0 0—Off Not displayed with cool-only systems (ISU 0170) or with
time Heat 90—90 seconds fan set to system control (ISU 0180 at 0).
0660 Extended Fan-on 0 0—Off Only shown for systems with cool stages (see ISU 0170).
time Cool 40—40 seconds
0670 Keypad Lockout 0 0—Unlocked Unlocked: All functions accessible.
1—Partial Lockout 1 Partial 1: Locks all but Holiday, Override, and Up/Down.
2—Partial Lockout 2 Partial 2: Locks all but Holiday and Override.
3—Fully Locked Full: Entire interface locked/non-functional.
0680 Temperature 2 1—Less Aggressive Only shown if system has heat stages (ISU 0170).
Control Heat 2—Standard Only integral gains affected. Affects control operation in
3—More Aggressive all control regimes (not just recovery or setpoint
change).
More Aggressive stops signal prior to reaching the
setpoint. (For use with oversized equipment.)

ACC-SVN61A-EN 19
 Operation

Table 5. Installer setup menu (continued)

Installer
Setup Installer Setup Default
Number Name Setting All Settings Notes
0685 Recovery Heat 5 0-20°F/hour Only shown if system has heat stages (ISU 0170).
Ramp Rate 0 disables ramped recovery (step setpoint change at
period start time).
0690 Temperature 2 1—Less Aggressive Only shown if system has cool stages (ISU 0170).
Control Cool 2—Standard Only integral gains affected. Affects control operation in
3—More Aggressive all control regimes (not just recovery or setpoint
change).
More Aggressive stops signal prior to reaching the
setpoint. (For use with oversized equipment.)
0695 Recovery Cool 3 0-20°F/hour Only shown if system has cool stages (ISU 0170).
Ramp Rate 0 disables ramped recovery (step setpoint change at
period start time).
0700 Temperature 0 -3 (-1.5)— -3°F (-1.5°C) This offset applies to both the control temperature and to
Display Offset -2 (-1.0)— -2°F (-1.0°C) the display temperature for indoor sensor (and remote
-1 (-0.5)— -1°F (-0.5°C) indoor sensor).
0 (0.0)—0°F (0.0°C)
1 (0.5)—1°F (0.5°C)
2 (1.0)— 2°F (1.0°C)
3 (1.5)—3°F (1.5°C)
0710 Restore Factory 0 0—No Resets all ISU parameters to default values and resets
Defaults 1—Yes the schedule to default Energy Star Table 6 on page 21.
Retains only calendar settings and time.
INSTALLER TESTS
Test 1 Installer Test 0 0—Off
Cool 1—Cool Stage 1
2—Cool Stage 2
Test 2 Installer Test 0 0—Off
Fan 1—Fan On
Test 3 Installer Test 0 0—Off
Heat 1—Heat Stage 1
2—Heat Stage 1 and 2
3—Heat Stage 1,2 and 3
Test 4 Installer Test 0 0—Auxiliary Heat Off
Auxiliary Heat 1—Auxiliary Heat On
Test 8 Installer Test 0 0—TOD/Economizer Off
TOD/Economizer 1—TOD/Economizer On

20 ACC-SVN61A-EN
 Settings

System Settings Minimum-Off Timer • If there is a call for cooling or

(Compressor Protection) heating during the Minimum-Off
• Heat—Thermostat controls the Time, the thermostat displays
heating system. The thermostat has an adjustable “Wait.”
• Off—Both heating and cooling Minimum-Off Timer that can be set
from zero to five minutes (Factory • When the Minimum Off Timer
systems are off. expires, “Cool On” or “Heat On”
Setting—five minutes). The
• Cool—Thermostat controls the Minimum-Off Timer can be (heat pumps only)” appears
cooling system. bypassed through the Installer solidly in the display and the
System Test or it can be bypassed compressor and fan turn on.
• Auto—Thermostat automatically
changes between heat and cool permanently by setting the
operation, depending on indoor Minimum-Off Timer to 0 minutes in Outdoor or Indoor
temperature. the Installer Setup. The Minimum-Off Temperature Sensor
Timer is activated after the
compressor turns off: Allow outdoor or indoor temperature
Fan Settings sensor to absorb the air for a
• If the thermostat is system minimum of five minutes before
• Auto —Fan runs only when powered (common wire), the taking a reading. See the Sensor
heating/cooling system is on. Minimum-Off Timer is also instructions for more information.
• On—Fan runs continuously. activated upon initial startup and
after power interruptions.
Table 6 and Table 7 show default Economizer/TOD Logic
program settings. See Owner’s
Guide for complete instructions to
change the program Table 8. Operation of terminal A.
Call Terminal A
for
Table 6. TB7220U Energy star default Occupancy Cool Economizer TOD
program settings
Occupied — Energized Energized
Setpoints Unoccupied Yes Energized De-
Schedule
Period Time Heat Cool Fan Setting energized

Occ1 8:00am 70°F (21°C) 75°F (25.5°C) On No De-energized De-

energized
Unocc1 10:00pm 55°F (10°C) 85°F (24°C) Auto
Override — Energized Energized
Occ2 1:00pm 70°F (21°C) 75°F (25.5°C) On
Unocc2 12:00pm 55°F (10°C) 85°F (24°C) Auto
(Noon) Heat Pump Temperature
Lockouts
Table 7. TB8220U Energy star default Dual Fuel Heat Pump and
program settings Outdoor Sensor
Setpoints
Schedule In this operation, there is no external
Period Time Heat Cool Fan Setting fossil fuel kit (dual fuel kit) installed;
Occ1 8:00am 70°F (21°C) 75°F (25.5°C) Auto the thermostat controls this function:
Unocc1 10:00pm 55°F (10°C) 85°F (24°C) Auto 1. Choose correct heat pump
Occ2a — — — — application in Installer Setup
Number 0170.
Unocc2a — — — —
2. Choose Outdoor Temperature
a The thermostat default setting is two period only. Sensor for Heat Pump
To use four periods, change the appropriate setup
parameter.
Temperature Lockouts Option in
Installer Setup Number 0340.
3. Choose appropriate Balance
Point Temperature in Installer
Setup Number 0350.

ACC-SVN61A-EN 21
 Settings

Operation in Heat Mode Above

Balance Point (Outdoor

OUTDOOR TEMPERATURE
Temperature) COMPRESSOR ONLY
AUXILIARY
When the outdoor temperature is 50 LOCKOUT
TEMPERATURE
above the selected Balance Point BOTH COMPRESSOR AND
Temperature (ISU 0350), only the AUXILIARY HEAT
COMPRESSOR
compressor operates and the fan (G 35 LOCKOUT
terminal) energizes when the AUXILIARY ONLY TEMPERATURE
thermostat calls for heat. M19950

Operation in Heat Mode Below Figure 37. Heat pump operation with lockout
Balance Point (Outdoor temperatures set.
Temperature)
When the outdoor temperature is
below the selected Balance Point
Temperature (ISU 0350), only the
Fossil Fuel (auxiliary heat) operates
and the fan (G terminal) does not
energize when the thermostat calls
for heat.

Heat Pump with Auxiliary

(Backup) Heat and Outdoor
Temperature Sensor
1. Choose correct heat pump
application in Installer Setup
Number 0170.
2. Choose Outdoor Temperature
Sensor for
3. Control Option in Installer Setup
Number 0340.
4. Choose Compressor Lockout
Temperature in Installer Setup
Number 0350.
5. Choose Auxiliary Lockout
Temperature in Installer Setup
Number 0360.
Note: There is a 5°F deadband
between Compressor and
Auxiliary Heat lockout
temperatures.

Operation in Heat Mode

When the outdoor temperature is:
• Below the Compressor Lockout
Temperature, only the Auxiliary
Heat operates.
• Above the Auxiliary Lockout
Temperature, only the
Compressor operates.
See Figure 37.
• Between the two temperatures,
both the Compressor and
Auxiliary Heat operate.

22 ACC-SVN61A-EN
 Troubleshooting

Table 9. Troubleshooting
Symptom Possible Cause Action
Display does not come on. Thermostat is not being powered. Check for 24 Vac between C and RC.
Check that batteries are installed correctly and are
good.
Temperature settings do not The upper or lower temperature limits were Check temperature setpoints.
change. reached. Check Installer Setup Numbers 0600 and 0610;
modify as needed.
The keypad is fully locked. Check Installer Setup Number 0670 to change
keypad locked options.
Heating or cooling does not come Thermostat minimum off-time is activated. Wait up to five minutes for the system to respond.
on.
System selection not set to Heat or Cool. Set system Selection to correct position.
System type Selection is incorrect. Check Installer Setup Number 0170 and make
sure correct System type is chosen.
Thermostat is calling for Heat Heating or cooling equipment is not Check wiring.
(Heat on) or Cool (Cool on) but no operating. Check Installer Setup Number 0170 and make
heating or cooling is running. sure correct system type is chosen.
Verify operation of equipment in System Test
mode.
Heat does not turn on (Heat On is Heating equipment failure. Check for 24 Vac at the equipment on the
solid in the display). secondary side of the transformer between power
and common. If voltage is not present, check the
heating equipment to find the cause of the
problem.

Check for 24 Vac between the heat terminal (W)

and transformer common. If 24 Vac is present, the
thermostat is functional. Check the heating
equipment to find the cause of the problem.
Loose or broken wire connection between Check for 24 Vac between the heat terminal (W)
thermostat and heating equipment. and transformer common. If voltage is not
present, check wire connection (loose or broken)
between the thermostat and the heating
equipment.
Heat pump puts out cool air in the Changeover Valve (Installer Setup Number Set Changeover Valve (Installer Setup Number
heat mode and warm air in the 0190) is not configured to match the 0190) to match the changeover required by the
cool mode. changeover required by the installed heat installed heat pump.
pump.
Both the heating and cooling The heating equipment is not a heat pump Set System Type (Installer Setup Number 0170) to
equipment are running at the but the System Type (Installer Setup match the installed heating and/or cooling
same time. Number 0170) is set to Heat Pump. equipment.
Heating and cooling wires are shorted Separate the shorted heating and cooling wires.
together.
Cooling does not turn on (Cool On Cooling equipment failure. Check for 24 Vac at the equipment on the
is solid in the display). secondary side of the transformer between power
and common. If voltage is not present, check the
cooling equipment to find the cause of the
problem.

Check for 24 Vac between the cool terminal (Y)

and transformer common. If 24 Vac is present, the
thermostat is functional. Check the cooling
equipment to find the cause of the problem.
Loose or broken wire connection between Check for 24 Vac between the cool terminal (Y)
thermostat and cooling equipment. and transformer common. If voltage is not
present, check the wire connection (loose or
broken) between the thermostat and the cooling
equipment.
Fan does not turn on in a call for Fan Control in Heating is set to Gas or Oil Set Fan Control in Heating to Electric Furnace
heat (electric furnace). Furnace (Setting 0180). (Setting 0180).
Heating equipment is running in Heating equipment is not a heat pump but Set System Type (Installer Setup Number 0170) to
the cool mode. System Type (Installer Setup Number 0170) match the installed heating and/or cooling
is set to Heat Pump. equipment.

ACC-SVN61A-EN 23
 Troubleshooting

Table 9. Troubleshooting (continued)

Symptom Possible Cause Action
Heating equipment does not turn Heating equipment is not a heat pump but Set System Type (Installer Setup Number 0170) to
off and heat temperature setting is System Type (Installer Setup Number 0170) match the installed heating and/or cooling
set below room temperature (Heat is set to Heat Pump. equipment.
On is not in the display).
Cannot set the system setting to System Type (Installer Setup Number 0170) Set System Type (Installer Setup Number 0170) to
Heat. is set to Cool Only. match the installed heating and/or cooling
equipment.

Cannot set the system setting to System Type (Installer Setup Number 0170) Set System Type (Installer Setup Number 0170) to
Cool. is set to Heat Only or Heat Only with Fan. match the installed heating and/or cooling
equipment.

Heat On is not in the display. System setting is not set to Heat and/or Set the system setting to Heat and set the
temperature setting is not set above room temperature setting above the room temperature.
temperature.
Cool On is not in the display. System setting is not set to Cool and/or the Set the system setting to Cool and set the
temperature setting is not set below room temperature setting below the room temperature.
temperature.
Wait is in the display. Compressor minimum off timer is active. Wait up to five minutes for the cooling or heating
(heat pump) equipment to turn on.

24 ACC-SVN61A-EN
 Specifications

Table 10. Electrical ratings

Voltage
Terminal (50/60 Hz) Running Current
W (Heating) 20 - 30 Vac 0.02 - 1.0A
Y (Cooling) 20 - 30 Vac 0.02 - 1.0A
G (Fan) 20 - 30 Vac 0.02 - 0.60A
A (Economizer/TOD) 20 - 30 Vac 0.02 - 1.0A

Temperature Setting Range:

• Heating: 40°F to 90°F
(4.5°C to 32°C).
• Cooling: 50°F to 99°F
(10°C to 37°C).

Operating Ambient
Temperature:
0°F to 120°F (-18°C to 49°C).

Shipping Temperature:
-30°F to 150°F (-34.4°C to 65.6°C).

Operating Relative Humidity

(Non-condensing):
5% to 90%.

Thermostat Dimensions:
3-3/4 in. (95 mm) high x 6 in. (152
mm) wide x 1-3/8in. (35 mm) deep.

Accessories:
BAYSTAT060A/ASYSTAT800A

ACC-SVN61A-EN 25
Literature Order Number ACC-SVN61A-EN
Date 10/06
Supersedes NEW
Stocking Location Electronic Only

The manufacturer has a policy of continuous product and product data improvement and reserves
the right to change design and specifications without notice.