Installation, Operation & Application Guide
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Parts Diagram
Configuration
switch
Reset switch
Left (system) button
Right (fan) button
Down button
Up button
Field programming pins
S1
Y2
W2
C
R
W
O/B
Y1
G W3
S2
RESET
CONFIG
FP
Specifications
Electrical rating:
• 24 VAC (18-30 VAC)
• 1 amp maximum per terminal
• 3 amp maximum total load
Temperature control range:
45°F to 90°F (7°C to 32°C)
Accuracy:
± 1°F (± 0.5°C)
System configurations:
3-stage heat, 2-stage cool, heat pump, gas, oil, electric
Timing:
Anti-short Cycle: 4 minutes (bypass anti-short cycle delay by returning to OFF mode for 5 seconds)
Backlight Operation: 10 seconds
Terminations:
S1, S2, R, C, W/O/B, Y1, W2, Y2, G, W3
Icon Descriptions
Cooling operation icon
Fan operation icon
Heating operation icon
Lock mode activated
Room temperature
offset activated
Package Contents/Tools Required
Package includes:
SC4812
thermostat on base, thermostat cover, wiring labels, screws and wall anchors,
Installation, Operation and Application Guide
Tools required for installation:
Drill with 3/16” bit, hammer, screwdriver
Important Safety Information
WARNING!
:
Always turn off power at the main power supply before installing, cleaning, or removing
thermostat.
• This thermostat is for 24 VAC applications only; do not use on voltages over 30 VAC
• Do not short across terminals of gas valve or system control to test operation; this will damage your thermostat
and void your warranty
• All wiring must conform to local and national electrical and building codes
• Do not use air conditioning when the outdoor temperature is below 50 degrees; this can damage your A/C system
and cause personal injuries
• Use this thermostat only as described in this manual
To Remove Existing Thermostat
ELECTRICAL SHOCK HAZARD
– Turn off power at the main service panel by removing the fuse
or switching the appropriate circuit breaker to the OFF position before removing the existing
thermostat.
1. Turn off power to the heating and cooling system by removing the fuse or switching the appropriate circuit
breaker off.
2. Remove cover of old thermostat. This should expose the wires.
3. Label the existing wires with the enclosed wire labels before removing wires.
4. After labeling wires, remove wires from wire terminals.
5. Remove existing thermostat base from wall.
6. Refer to the following section for instructions on how to install this thermostat.
To Install Thermostat
ELECTRICAL SHOCK HAZARD
– Turn off power at the main service panel by removing the fuse
or switching the appropriate circuit breaker to the OFF position before removing the existing
thermostat.
IMPORTANT:
Thermostat installation must conform to local and national building and electrical codes and
ordinances.
Note:
Mount the thermostat about five feet above the floor. Do not mount the thermostat on an outside
wall, in direct sunlight, behind a door, or in an area affected by a vent or duct.
1. Turn off power to the heating and cooling system by removing the fuse or switching the appropriate circuit
breaker off.
2. To remove cover, pull gently at the seam at the top.
3. Put thermostat base against the wall where you plan to mount it (Be sure wires will feed through the wire opening
in the base of the thermostat).
4. Mark the placement of the mounting holes.
5. Set thermostat base and cover away from working area.
6. Using a 3/16” drill bit, drill holes in the places you have marked for mounting.
7. Use a hammer to tap supplied anchors in mounting holes.
8. Align thermostat base with mounting holes and feed the control wires through slit in thermal intrusion barrier and
into wire opening.
9. Use supplied screws to mount thermostat base to wall.
10. Insert stripped, labeled wires in matching wire terminals.
CAUTION!
:
Be sure exposed portion of wires does not touch other wires.
11. Gently tug wire to be sure of proper connection. Double check that each wire is connected to the proper
terminal.
12. Turn on power to the system at the main service panel.
13. Configure thermostat to match the type of system you have.
14. Replace cover on thermostat by snapping it in place.
15. Test thermostat operation as described in “Testing the Thermostat”.
Wiring Diagrams
Heat/Cool Systems
120
VAC
24 VAC
Heat #1
Cool #1
Heat #2
Cool #2
Fan
Heat #3
Transformer
Optional
remote or
outdoor sensor
Single Compressor
heat pump with electric backup
120
VAC
24 VAC
Reversing Valve
Compressor
Auxiliary Heat #1
Fan
Auxiliary Heat #2
Transformer
Optional
remote or
outdoor sensor
Dual Compressor
heat pump with electric backup
120
VAC
24 VAC
Reversing Valve
Compressor #1
Auxiliary Heat
Compressor #2
Fan
Transformer
Optional
remote or
outdoor sensor
Configuration Mode
OFF
PM
1. Verify the
SC4812
is in the
OFF
mode.
Press the
SYS
(left) button until off mode displays.
The configuration mode is used to set the
SC4812
to match your heating/cooling system. The
SC4812
functions
with heat pump, air conditioning, gas, oil or electric heat systems.
To configure the
SC4812
, perform the following steps:
2. Remove the cover of the thermostat by gently pulling near one of the
corners at the top of the thermostat.
Note:
Do not force open. Use a small coin or slotted screwdriver to release tabs if necessary.
Press the
up
or
down
button to change settings within each screen.
Down
button
Up
button
To exit configuration mode, press the
CONFIG
switch for 1 second.
Press the
right
button to advance to the next screen.
Note:
Pressing the
left
button will return you to the previous screen.
Left
button
Right
button
3. Press the
CONFIG
button for 1 second while the
SC4812
is in
OFF
mode.
CONFIG
3 Heat/2 Cool
Auto Changeover
Hardwire
SC4812
• Configurable
• 3-Stage Heat/2-Stage Cool Systems
• 3-Stage Heat Pump Systems
• Large Display With Backlight
• Selectable Fahrenheit or Celsius
• Compatible with Gas, Oil, or Electric
• Dual Fuel Compatible
• SimpleSet™ Field Programming
• Status Indicator Light
• Relay Outputs
(minimum voltage drop in thermostat)
• Remote Sensor Compatible
• Ideally Suited for:
–
Residential (New Construction/Replacement)
–
Light Commercial
Non-Programmable Electronic Thermostat
Single Compressor
heat pump with gas/oil backup
120
VAC
24 VAC
Reversing Valve
Compressor
Oil/Gas Heat
Fan
Dual Compressor
heat pump with gas/oil backup
120
VAC
24 VAC
Reversing Valve
Compressor #1
Oil/Gas Heat
Fan
Compressor #2
Transformer
Optional
remote or
outdoor sensor
Transformer
Optional
remote or
outdoor sensor
Remote Sensor Installation (Optional)
Terminals S1 and S2 can be used for an outdoor sensor or for an indoor remote sensor.
The outdoor sensor is used to change system operation based on the outdoor temperature. It can be used for heat
pumps with gas/oil backup or heat pumps with electric backup.
The indoor remote sensor is used to read the indoor temperature in a different location. This is beneficial when the
thermostat is not mounted in the ideal location.
1. Remove cover from remote sensor housing.
2. Select an appropriate location for mounting the remote sensor.
3. Mount remote sensor unit using hardware provided.
4. Install two strand shielded wire between remote sensor and thermostat. Shielded wire is recommended.
Do not
run remote sensor wire in conduit with other wires.
•
Wire 1
should run between the S1 terminal on the thermostat and the S1 terminal on the remote sensor
•
Wire 2
should run between the S2 terminal on the thermostat and the S2 terminal on the remote sensor
• Connect the shielding of the wire to the S2 terminal on the thermostat
5. Configure the thermostat to operate with the remote indoor sensor (see Configuration Mode setting 17) or use it
for an outdoor sensor for heat pump systems.
Note:
Remote or outdoor sensor
reading can be displayed
by simultaneously pressing
the
Down
and
SYS
buttons.
Remote Sensor: (Shown: Optional ICM ACC-RT103 Remote Indoor Sensor;
for outdoor sensor, order ACC-OD103.)
Terminal Designator Descriptions
1
ST
Cool
2
ND
Cool
1
ST
Heat
2
ND
Heat
3
RD
Heat
Heat/Cool
Y1, G
YI, Y2, G
W1, G*
W1, W2, G*
W1, W2, W3, G*
Heat Pump (One Compressor)
Y1, G, O
Y1, G, O
Y1, G, B
Y1, W2, G, B
Y1, W2, W3, G, B
Heat Pump (Two Compressors)
Y1, G, O
Y1, Y2, G, O
Y1, G, B
Y1, Y2, G, B
Y1, Y2, W2, G, B
Dual Fuel (One Compressor)
Y1, G, O
Y1, G, O
Y1, G, B
W2
W2, W3
Dual Fuel (Two Compressors)
Y1, G, O
Y1, Y2, G, O
Y1, G, B
Y1, Y2, G, B
W2
Emergency Heat (Heat Pump Only)
N/A
N/A
W2, G
W2, W3, G
N/A
* G not energized when configured as a gas/oil system
SC4812 Output Chart
The
SC4812
thermostat is configurable for all systems. The configuration directly affects the outputs.
Use the output chart to correctly configure and wire the thermostat to your system.
R – 24 VAC hot
C – 24 VAC common
W1/O/B – Configurable
W1 – 1st stage heat for non-heat pump systems
O – cool active reversing valve
B – heat active reversing valve
Y1 – 1st stage cool, 1st stage heat for heat pumps
W2 – 2nd stage heat for 1 compressor heat pump and non-hp, 3rd stage heat for 2 compressor heat pump
systems
Y2 – 2nd stage cool for 2 compressor systems, 2nd stage heat for 2 compressor heat pump systems
G – Fan
W3 – 3rd stage heat for non-hp systems and 1 compressor heat pump systems
Configuration Mode Settings
4.
3
rd
Stage Temperature Differential
(1°F to 5°F) (0.5°C to 2.5°C)
Set the number of degrees between when stage 2 turns on and when stage 3 turns on.
Press the
up
or
down
button to set differential value.
Press the
right
button to advance to the next screen.
3.
2
nd
Stage Temperature Differential
(1°F to 5°F) (0.5°C to 2.5°C)
Set the number of degrees between when stage 1 turns on and when stage 2 turns on.
Press the
up
or
down
button to set differential value.
Press the
right
button to advance to the next screen.
2.
1
st
Stage Temperature Differential
(1°F to 5°F) (0.5°C to 2.5°C)
Set the number of degrees between your “setpoint” temperature and your “turn on”
temperature.
Press the
up
or
down
button to set differential value.
Press the
right
button to advance to the next screen.
1.
Temperature Scale
(F or C)
Choose Fahrenheit or Celsius.
Press the
up
or
down
button to select.
Press the
right
button to advance to the next screen.
The setup screens for Configuration Mode are as follows:
6.
Minimum Deadband
(1°F to 9°F) (1°C to 5°C)
Set the minimum separation between heat setpoint and cool setpoint in
Auto
Changeover
Mode.
Press the
up
or
down
button to set deadband value.
Press the
right
button to advance to the next screen.
5.
Staged Off Outputs
Select whether the outputs for heating and cooling are staged off independently or
are satisfied simultaneously.
1 = outputs staged off independently
0 = outputs off simultaneously (best for dual fuel)
Note:
For 2 compressor heat pumps and multi-stage gas/oil systems, stage 3 is
staged off independently when
SO
is set to
O
.
Press the
up
or
down
button to set.
Press the
right
button to advance to the next screen.
7.
System
– Set for heat pump, non-heat pump, reversing valve operation and number of compressors in your
system.
Press the
up
or
down
button to select.
Press the
right
button to advance to the next screen.
Choose
System
Reversing Valve
Active
Number of Compressors
or Compressor Stages
Type of
Heat
Heat Pump
HP
O
1
HP
b
1
HP
O
2
HP
b
2
Non-Heat
Pump
Heat
Gas
Heat
Electric
