Smart Si Digital Thermostat

ecobee Smart Si Thermostat

The ecobee Smart Si Thermostat is a programmable digital thermostat designed to control compatible residential heating and cooling equipment. It features a color display, physical navigation buttons, multi-stage HVAC control, configurable operating thresholds, equipment testing, and maintenance alerts.

The Smart Si supports conventional heating and cooling systems with up to two heating and two cooling stages. It also supports compatible heat pump systems with up to three heating and two cooling stages, including auxiliary heat. Supported equipment includes gas, oil, and electric heating systems, geothermal heat pumps, dual-fuel systems, and boilers.

The thermostat operates using a 24 VAC power supply from the connected HVAC equipment. Installation involves disconnecting power, removing the previous thermostat, mounting the Smart Si backplate, connecting the appropriate wiring, and configuring the heating and cooling equipment.

The thermostat includes configurable compressor protection, heating and cooling thresholds, temperature correction, equipment testing, reset functions, and HVAC maintenance reminders.

Important: The Smart Si is intended for installation by trained service professionals. Electrical power must be disconnected before installation or wiring work begins.

Product Overview

The ecobee Smart Si provides digital temperature control for compatible low-voltage HVAC systems.

It allows the installer to configure the connected heating and cooling equipment, adjust equipment operating thresholds, and verify operation through the Test Equipment menu.

The thermostat also provides configurable alerts for heating and cooling failures, temperature limits, furnace filter replacement, UV lamp servicing, and scheduled HVAC maintenance.

Main Features

• Multi-stage HVAC control: Supports up to two conventional heating and cooling stages.
• Heat pump compatibility: Supports up to three heating stages and two cooling stages on compatible heat pump systems.
• Color display: Shows temperature, menus, and configuration information.
• Navigation buttons: Provides Up, Down, Left, Right, OK, MENU, and BACK controls.
• HVAC equipment configuration: Supports furnace, air conditioner, and heat pump settings.
• Compressor protection: Allows a configurable minimum compressor off time.
• Automatic heating and cooling changeover: Available through the Allow Auto Heat/Cool setting.
• Heat pump configuration: Supports geothermal and air-to-air heat pump options.
• Auxiliary heat control: Provides configurable auxiliary heating operation.
• Temperature correction: Allows an offset between measured and displayed temperatures.
• Installer access code: Protects installation settings using a four-digit code.
• Equipment testing: Allows connected HVAC components to be tested individually.
• Hardware reboot: Restarts the thermostat without removing saved configuration.
• HVAC settings reset: Restores equipment settings to factory defaults.
• Maintenance reminders: Supports furnace filter, UV lamp, and HVAC service reminders.
• Temperature alerts: Reports conditions above or below configured temperature thresholds.
• Heating and cooling alerts: Identifies equipment that fails to respond as expected.

HVAC System Compatibility

The ecobee Smart Si is designed for low-voltage heating and cooling systems.

It does not support line-voltage or millivolt heating and cooling equipment.

Supported HVAC Equipment

Conventional Heating and Cooling

The thermostat supports:

• Single-stage heating and single-stage cooling.
• Single-stage heating and two-stage cooling.
• Two-stage heating and single-stage cooling.
• Two-stage heating and two-stage cooling.

Heat Pump Systems

The Smart Si supports compatible heat pumps with auxiliary heating.

The installation manual includes wiring diagrams for:

• Single-stage heat pumps with auxiliary heat.
• Two-stage heat pumps with auxiliary heat.

Boiler Systems

The thermostat also supports boiler installations with air handlers and cooling equipment.

The illustrated configurations include single-stage and two-stage boilers with single-stage or two-stage cooling.

Technical Specifications

Parts and Components

The ecobee Smart Si includes a thermostat body, color display, navigation buttons, and a removable backplate with wiring terminals.

Color Display

The Smart Si uses a color screen to display temperature information and configuration menus.

The display also provides an on-screen keyboard when text or numerical information must be entered.

Thermostat Backplate

The removable backplate provides access to the wiring terminals.

The thermostat attaches to the backplate after the wiring connections are completed.

Hardware Reset Button

The hardware reset button is accessible through an opening at the bottom-left corner of the thermostat.

It restarts the thermostat without deleting programming or configuration settings.

Control Buttons and Display Guide

The Smart Si is operated using the physical navigation buttons on the right side of the thermostat.

Navigation Button Functions

How to Increase or Decrease Temperature

1. Display the Home screen.
2. Press ▲ to increase the temperature.
3. Press ▼ to decrease the temperature.

Each button press changes the selected temperature by 1°F or 0.5°C.

How to Use the On-Screen Keyboard

When the thermostat requires text entry:

1. Use the arrow buttons to highlight a character.
2. Press OK to enter the character.
3. Repeat until the required information is entered.
4. Select the uppercase option for capital letters.
5. Select the symbols option when needed.
6. Use the delete control to correct mistakes.
7. Select Save to keep the entered information.

Press BACK to cancel the changes.

Wiring Requirements

The Smart Si must be connected to HVAC equipment using low-voltage thermostat cable.

Maximum Thermostat Wire Length

Terminal Descriptions and Electrical Ratings

RC and RH Jumper

The thermostat has a factory-installed jumper between RC and RH.

For two-transformer applications, the jumper must be removed according to the appropriate wiring diagram.

Important: Do not leave exposed bare copper conductors on unused wires.

Important Safety Instructions

The ecobee Smart Si connects to HVAC electrical control circuits.

Incorrect installation or wiring may cause electrical shock or equipment damage.

Electrical Safety

• Disconnect electrical power before installing the thermostat.
• Do not connect or disconnect thermostat wiring while the HVAC system is energized.
• Use the thermostat only with compatible low-voltage heating and cooling equipment.
• Do not connect the thermostat to line-voltage systems.
• Do not connect the thermostat to millivolt heating or cooling systems.
• Follow all applicable local electrical codes.
• Use the correct wiring diagram for the installed HVAC equipment.
• Check the factory RC/RH jumper before connecting the thermostat.
• Remove the RC/RH jumper when required for a two-transformer installation.
• Make sure unused wires do not have exposed copper conductors.
• Have installation and equipment servicing performed by trained professionals.

Compressor Protection Warning

Warning: Compressor protection and minimum runtime features are not enforced during the Test Equipment procedure.

The technician must avoid rapid compressor cycling while testing the system.

Mercury Disposal Notice

The ecobee Smart Si does not contain mercury.

If replacing an older thermostat containing mercury, contact the local waste-management authority for appropriate disposal instructions.

Do not place a mercury-containing thermostat in regular household trash.

Radio Frequency Safety

The Smart Si must maintain a separation distance of at least 8 inches (20 cm) between the device and people to meet the stated FCC/IC radio-frequency exposure requirements.

Unauthorized modifications may void the user’s authority to operate the equipment.

Before Installation

Before installing the Smart Si, identify the HVAC equipment and prepare the required wiring connections.

Installation Preparation

1. Identify the type of heating and cooling equipment.
2. Confirm that the system operates using compatible low-voltage controls.
3. Determine the number of heating and cooling stages.
4. Identify whether the installation uses one or two transformers.
5. Locate the HVAC power disconnect.
6. Turn off electrical power.
7. Identify the existing thermostat wires.
8. Prepare the thermostat backplate and mounting hardware.
9. Select an appropriate wall location.
10. Keep the applicable wiring diagram available.

Choosing the Thermostat Location

The ideal installation location is approximately 5 feet (1.5 meters) above floor level in the main living area.

Recommended Placement

Install the thermostat in a location where it can measure the indoor temperature without interference from nearby heat sources or restricted airflow.

Locations to Avoid

Do not install the Smart Si:

• Near incandescent lights or other heat sources.
• Near heating or cooling supply outlets.
• In direct sunlight.
• On exterior walls.
• On uninsulated or poorly insulated walls.
• In kitchens or areas with unusually high heat or humidity.
• In locations with restricted airflow.

Smart Si Installation Instructions

The thermostat installation has five main steps.

Step 1: Turn Off HVAC Power

Before removing the existing thermostat:

1. Locate the power disconnect for the heating and cooling equipment.
2. Turn off electrical power.
3. Confirm that power is disconnected before working on the thermostat wiring.

Caution: Electrical power must remain disconnected throughout the wiring procedure.

Step 2: Remove the Existing Thermostat

1. Disconnect the wires from the existing thermostat.
2. Remove the thermostat from the wall if installing the Smart Si in the same location.
3. Keep the wires accessible for the new installation.

Step 3: Install the Backplate

1. Gently separate the Smart Si backplate from the thermostat.
2. Position the backplate against the wall.
3. Pass the existing thermostat wires through the backplate opening.
4. Use the backplate as a template to mark the mounting holes.
5. Move the backplate aside.
6. Prepare the mounting holes.
7. Install the supplied drywall plugs or suitable wall anchors.
8. Secure the backplate using the supplied screws.

The mounting holes accommodate #6 pan-head screws.

Using the supplied fasteners is recommended for proper fitting of the thermostat housing.

Step 4: Connect the Wiring

1. Identify the wiring diagram that matches the installed HVAC system.
2. Connect the low-voltage wires to the corresponding terminals.
3. Check the RC/RH jumper configuration.
4. Remove the jumper when required for a two-transformer application.
5. Check that unused wires do not have exposed bare copper.
6. Align the thermostat pins with the terminal block on the backplate.
7. Attach the thermostat to the backplate.

Step 5: Restore HVAC Power

After completing the wiring:

1. Restore power to the heating and cooling equipment.
2. Allow the thermostat to start automatically.

The Smart Si receives its operating power from the connected HVAC equipment.

Smart Si Thermostat Wiring Diagrams

The installation manual provides wiring diagrams for ten HVAC configurations.

Single-Stage Heating and Cooling Wiring

The single-stage furnace and air conditioner diagram uses terminals for:

• First-stage heating.
• First-stage cooling.
• Fan operation.
• Transformer power.
• Common connection.

The W terminal controls first-stage heating, while Y controls the first-stage compressor.

Single-Stage Heating With Two-Stage Cooling

For a single-stage furnace and two-stage air conditioner:

• W provides first-stage heating control.
• Y provides first-stage cooling control.
• Y2 provides second-stage cooling control.
• G provides fan control.

The remaining power and common connections must match the equipment diagram.

Two-Stage Heating With Single-Stage Cooling

For a two-stage furnace and single-stage air conditioner:

• W provides first-stage heating.
• W2 provides second-stage heating.
• Y provides first-stage cooling.
• G provides fan control.

Two-Stage Heating and Cooling

For a conventional two-stage heating and two-stage cooling system:

Single-Stage Heat Pump With Auxiliary Heat

The heat pump wiring diagram includes:

• First-stage compressor.
• Reversing valve.
• Fan control.
• Auxiliary heat.
• Power and common connections.

The W (O/B) terminal provides the reversing valve changeover function.

The W2 (AUX) terminal supports auxiliary heating.

Two-Stage Heat Pump With Auxiliary Heat

The two-stage heat pump configuration adds second-stage compressor control through Y2.

The connected equipment must be configured correctly through the Heat Pump settings.

Boiler With Air Handler Wiring

The manual includes boiler and air handler configurations with single-stage and two-stage cooling.

Important: For the illustrated boiler applications with separate transformers:

• Remove the factory RH/RC jumper.
• Connect the C terminal to the heating transformer common.
• Follow the wiring arrangement for the boiler, air handler, and cooling equipment.

These wiring connections must be completed by a qualified HVAC installer.

Configuring the Smart Si Thermostat

After installing the thermostat, configure the connected HVAC equipment.

The Equipment menu identifies the heating and cooling components and determines which operating settings are available.

How to Open Equipment Settings

1. Press MENU from the Home screen.
2. Select Settings.
3. Open Installation Settings.
4. Select Equipment.
5. Configure the installed heating and cooling devices.

Heat Pump Configuration

The Heat Pump menu supports compatible heat pump equipment with auxiliary heating.

Heat Pump Settings

Geothermal Heat Pump

Select Yes when using a geothermal heat pump.

Select No for an air-to-air heat pump.

The selection allows the thermostat to apply the corresponding equipment settings.

O/B Energize on Cool

Minimum Compressor Off Time

The minimum compressor off time can be configured between:

240 and 900 seconds.

The setting provides a delay between compressor operating cycles.

Minimum Outdoor Temperature

The Minimum Outdoor Temperature setting disables compressor operation when the outside temperature reaches the configured minimum.

The adjustable range is:

0°F–65°F.

The function can also be disabled.

An internet connection is required for this feature to operate properly.

Allow Heat Pump With Auxiliary Heat

This setting determines whether auxiliary heat can operate alongside the heat pump.

When Yes is selected, auxiliary heat can operate together with the heat pump.

When No is selected, the thermostat shuts down the heat pump before energizing auxiliary heat under the described conditions.

This option is available when the Comp to Aux Temp Delta and Comp to Aux Runtime settings are both set to Auto.

Furnace Configuration

The Furnace menu configures conventional heating equipment.

It supports up to two heating stages.

Furnace Settings

Furnace Type

Select the option that matches the installed heating equipment.

This helps the thermostat apply the operating characteristics associated with the selected furnace.

Heat Fan Control

Heat Fan Control determines whether the Smart Si or the HVAC equipment controls fan operation during heating.

The installation manual states that the HVAC equipment normally controls the fan during heating cycles.

Air Conditioner Configuration

The Air Conditioner menu supports up to two stages of cooling.

Single-Stage Cooling

Configure the installed first-stage air conditioner.

Two-Stage Cooling

If the HVAC system has a second cooling stage, enable the Y2 relay.

HVAC Threshold Settings

Thresholds control temperature differences, compressor timing, equipment runtime, and stage activation.

How to Open Threshold Settings

1. Press MENU.
2. Select Settings.
3. Open Installation Settings.
4. Select Thresholds.
5. Configure the required settings.

Complete the Equipment configuration before setting thresholds.

Only options relevant to the installed equipment appear in the menu.

Main Threshold Settings

Automatic Heat/Cool Changeover

The Allow Auto Heat/Cool setting makes automatic heating and cooling changeover available as a system mode.

Heat/Cool Minimum Delta

The minimum delta prevents the heating and cooling setpoints from being placed too close together.

The adjustable range is 2°F–10°F.

The default is 5°F.

Compressor Protection Settings

Minimum Cycle Off Time

The Minimum Cycle Off Time setting determines how long the compressor must remain off between cycles.

Available range:

240–900 seconds.

This prevents short cycling that could affect compressor operating life.

Minimum Outdoor Temperature

The Minimum Outdoor Temperature setting disables the compressor below the selected outdoor temperature threshold.

An internet connection is required for this function.

Auxiliary Heat Settings

Maximum Outdoor Temperature

The Auxiliary Heat Maximum Outdoor Temperature setting prevents auxiliary heating from operating when the outdoor temperature exceeds the selected limit.

Heating and Cooling Differential Settings

Heat Differential Temperature

The heating differential determines how far the current temperature must fall below the heating setpoint before the thermostat requests heat.

Available range:

0°F–3°F in 0.5°F increments.

Smaller differentials produce shorter heating cycles, while larger differentials produce longer cycles.

Cool Differential Temperature

The cooling differential determines how far the current temperature must rise above the cooling setpoint before the thermostat requests cooling.

Available range:

0°F–3°F in 0.5°F increments.

Heat and Cool Dissipation Settings

Heat Dissipation Time

This setting controls how long the fan continues operating after the heating call ends.

The additional fan runtime circulates heated air remaining in the ductwork.

Cool Dissipation Time

This setting controls how long the fan continues operating after the cooling call ends.

The additional runtime circulates cooled air remaining in the ductwork.

Advanced HVAC Settings

The Smart Si supports additional settings for multi-stage HVAC operation.

Reverse Staging

When Reverse Staging is enabled, the thermostat can disengage higher equipment stages as the temperature approaches the setpoint.

The equipment begins in first stage.

If the configured temperature difference is exceeded, the second stage activates.

As the temperature approaches the desired setting, the second stage disengages while the first stage continues operating.

Stage 2 Temperature Delta

The Stage 2 Temperature Delta setting provides options for higher-stage activation.

Available settings:

• Auto.
• 1°F–10°F.

Stage 1 Maximum Runtime

This setting limits the time first-stage equipment operates before the next stage is requested.

Available settings:

• Auto.
• 10–120 minutes.

Compressor to Auxiliary Heat Settings

The Smart Si provides:

• Comp to Aux Temp Delta.
• Comp to Aux Runtime.

The manual identifies Auto settings and configurable temperature or runtime-related options for these controls.

These settings must be configured according to the connected heat pump and auxiliary heating equipment.

Cool Minimum On Time

The Cool Minimum On Time setting prevents the cooling system from stopping before its configured minimum runtime.

Heat Minimum On Time

The Heat Minimum On Time setting performs the same function for heating equipment.

Temperature Correction

Temperature Correction allows an offset between the temperature at the thermostat and the displayed temperature.

Available Adjustment

A trained installer can use this function when the thermostat location requires a temperature reading adjustment.

Installer Access Code

The Smart Si provides a four-digit installer code to restrict unauthorized changes to installation settings.

The manual identifies the preprogrammed code as:

3262

The code can be enabled through the installer settings.

How to Test HVAC Equipment

The Test Equipment menu allows a technician to verify the connected HVAC components.

Testing Instructions

1. Press MENU.
2. Select Settings.
3. Open Installation Settings.
4. Select Test Equipment.
5. Press OK.
6. Select the connected equipment.
7. Turn the selected component on or off.
8. Exit the menu when testing is complete.

The equipment turns off when the Test Equipment menu is exited.

Warning: Compressor protection and minimum runtime features are not active during equipment testing. Avoid rapid compressor cycling.

Reset and Reboot Instructions

The Smart Si provides different reset functions for equipment configuration and thermostat operation.

Reset HVAC Equipment Settings

This restores the HVAC equipment configuration to factory defaults without changing unrelated user settings.

1. Press MENU.
2. Select Settings.
3. Select Reset.
4. Choose HVAC Equipment Settings.
5. Select Yes.

Reset All Settings

Reset All Settings restores the thermostat to its original factory configuration.

This includes user settings and registration information.

Hardware Reboot

A hardware reboot can be used if static electricity or a power surge interrupts thermostat operation.

The physical reset button is located through an opening at the bottom-left corner of the thermostat.

Pressing this button reboots the thermostat without changing saved programming or configuration options.

HVAC Reminders and Alerts

The Smart Si provides reminders for maintenance tasks and alerts for abnormal heating and cooling conditions.

How to Configure Reminders and Alerts

1. Press MENU.
2. Select Reminders and Alerts.
3. Choose the reminder or alert.
4. Configure the available settings.

Maintenance Reminders

HVAC Service Reminder

The HVAC Service reminder indicates that regularly scheduled equipment maintenance is required.

Available settings include:

• Last Service date.
• Reminder On or Off.
• Maintenance frequency in months.

The alert can display technician contact information.

For registered thermostats, the reminder can also be sent by email and displayed through the web portal.

Furnace Filter Reminder

The Furnace Filter reminder indicates when the filter needs cleaning or replacement.

The following settings can be configured:

• Last Filter Change date.
• Reminder On or Off.
• Reminder frequency.

UV Lamp Reminder

The UV Lamp reminder identifies when the connected HVAC equipment’s UV lamp requires cleaning or replacement.

The reminder includes configurable service dates and maintenance intervals.

Temperature Alerts

The Smart Si can generate alerts when indoor temperature moves above or below the configured limits.

Low Temperature Alert

High Temperature Alert

Display Alerts on Thermostat

The thermostat can be configured not to display alerts on its screen.

When registered, supported alerts can continue to appear through the web portal and email.

Enable Heating/Cooling Alerts

The heating and cooling failure alerts can be enabled or disabled.

When disabled, the related alerts will not appear on the thermostat screen, web portal, or email notifications.

Alert Messages and Meanings

Heat Not Responding

This alert indicates that the connected heating system has not provided the required heating response.

The heating equipment should be checked by a qualified HVAC technician.

Cool Not Responding

This alert indicates that the cooling system has failed to provide the expected cooling response.

The installed cooling equipment should be inspected.

Auxiliary Heat Run Time

This alert indicates that the auxiliary heat source is running too frequently.

The auxiliary heating configuration and equipment operation should be reviewed.

Auxiliary Outdoor Temperature

This alert indicates that auxiliary heating was requested when the outdoor temperature exceeded the programmed limit.

Troubleshooting Guide

The following installation checks and alert responses are based on the Smart Si thermostat’s documented power, configuration, test, reset, and notification functions.

Smart Si Thermostat Not Turning On

The Smart Si receives electrical power from the connected HVAC equipment.

If the thermostat does not start after installation, the installer should verify that HVAC power has been restored and that the wiring matches the relevant installation diagram.

Electrical troubleshooting should be completed by a qualified HVAC professional.

Smart Si Thermostat Not Heating

If heating equipment fails to respond:

1. Check whether the thermostat displays a Heat Not Responding alert.
2. Review the configured heating equipment.
3. Confirm that the equipment settings match the installed system.
4. Arrange professional HVAC inspection if the heating equipment is not operating as required.

Smart Si Thermostat Not Cooling

If cooling equipment does not respond:

1. Check whether a Cool Not Responding alert is displayed.
2. Review the installed air conditioner configuration.
3. Confirm the number of cooling stages.
4. Check that Y2 is enabled when a second cooling stage is installed.
5. Have the cooling equipment inspected if the problem continues.

Smart Si Compressor Not Restarting Immediately

The Smart Si includes a configurable compressor minimum off time.

The adjustable range is 240–900 seconds.

This setting prevents rapid compressor restarting.

Allow the configured protection interval before expecting the compressor to restart.

Smart Si Temperature Reading Needs Adjustment

The thermostat provides a Temperature Correction setting.

This allows a technician to apply an offset of up to ±10°F in 0.5°F increments.

The offset should be configured according to the temperature at the thermostat location.

Smart Si Hardware Reset

If static electricity or a power disturbance interrupts operation, use the physical hardware reset button.

The button is accessible through the opening at the bottom-left corner of the thermostat.

A hardware reboot preserves the programmed settings and equipment configuration.

Maintenance Instructions

The Smart Si provides maintenance reminders for the connected HVAC equipment.

Maintenance Reminder Functions

The installer or user can configure maintenance intervals according to the equipment’s service requirements.

FCC and Regulatory Information

The ecobee Smart Si complies with applicable FCC requirements for Class B digital devices under Part 15 of the FCC Rules.

FCC Operating Conditions

The device is designed to meet applicable radio-frequency interference requirements.

If radio or television interference occurs:

• Reorient or relocate the receiving antenna.
• Increase the distance between the equipment and receiver.
• Connect the affected equipment to a different electrical circuit.
• Consult the dealer or an experienced radio or television technician.

RF Exposure Requirements

Maintain at least 8 inches (20 cm) of separation between the device and people.

Regulatory Identifiers

Unauthorized Modifications

Changes or modifications not expressly approved by ecobee may void the user’s authority to operate the equipment.

Warranty Information

The ecobee Smart Si Thermostat includes a three-year limited warranty covering qualifying defects in materials and workmanship.

Warranty Coverage

During the warranty period, ecobee may repair or replace a qualifying defective thermostat.

Repaired or replacement devices remain covered for the longer of:

• The remaining original warranty period.
• 90 days.

How to Request Warranty Service

1. Contact ecobee Customer Service at 1-877-932-6233.
2. Explain the product problem.
3. Follow the warranty service instructions.
4. Complete the required return or replacement procedure.

ecobee determines whether a replacement can be supplied or whether the thermostat must be returned for inspection.

Warranty Service Through an HVAC Contractor

If the thermostat was purchased through a third-party contractor, the customer may contact that contractor for an equivalent replacement.

The contractor must determine that the thermostat is defective and eligible for warranty service.

Advanced Replacement

ecobee may provide an equivalent replacement before receiving the defective thermostat.

A temporary credit card hold may be required until the returned product has been received.

Warranty Exclusions

The limited warranty does not cover removal or reinstallation costs.

It also excludes damage resulting from:

• Abnormal use or storage conditions.
• Improper maintenance.
• Abuse or neglect.
• Electrical faults.
• Improper handling.
• Accidents.
• Natural events.
• Unauthorized repairs or modifications.
• Improper installation.
• Installation not performed by a licensed HVAC contractor.

Important: The warranty excludes thermostats that were not installed by a licensed Heating, Ventilating, and Air Conditioning contractor.

Warranty Limitations

ecobee’s warranty remedy is limited to repair or replacement under the stated conditions.

Additional rights and limitations may vary by jurisdiction.

Customer Support Information

ecobee provides technical assistance for thermostat installation, HVAC configuration, and warranty service.

When to Contact ecobee Support

Contact ecobee for assistance with:

• HVAC system compatibility.
• Thermostat wiring.
• Equipment configuration.
• Heat pump settings.
• Thermostat startup problems.
• Installer settings.
• Equipment operation.
• Warranty service.

Frequently Asked Questions

How do I install the ecobee Smart Si thermostat?

Disconnect HVAC power, remove the existing thermostat, and mount the Smart Si backplate approximately 5 feet above the floor in a suitable indoor location. Connect the low-voltage wiring according to the correct HVAC wiring diagram, attach the thermostat body, and restore power. The thermostat turns on automatically when power is supplied by the connected equipment. Installation should be completed by a trained HVAC professional.

What HVAC systems are compatible with the ecobee Smart Si?

The Smart Si supports conventional heating and cooling systems with up to two heating and two cooling stages. It also supports compatible heat pumps with up to three heating stages and two cooling stages, geothermal heat pumps, dual-fuel systems, and boilers. It is not compatible with line-voltage or millivolt systems.

What are the ecobee Smart Si wiring terminals?

The Smart Si uses N/C, Y, W (O/B), G, RC, RH, C, Y2, and W2 (AUX) terminals. These provide compressor, heating, fan, transformer power, common, reversing valve, and auxiliary heating connections. The correct terminal arrangement depends on the HVAC equipment. The RC/RH factory jumper must be removed for applicable two-transformer installations.

How do I access the installer settings on the Smart Si thermostat?

Press MENU, select Settings, open Installation Settings, and choose Equipment or Thresholds. The installer can configure heating and cooling equipment, heat pump settings, compressor protection, stage operation, and other available options. The manual identifies the preprogrammed four-digit installer code as 3262.

How do I reset the ecobee Smart Si thermostat?

For an HVAC configuration reset, open MENU → Settings → Reset → HVAC Equipment Settings and confirm the reset. To restore all settings, use Reset All Settings. To reboot the thermostat without changing saved programming, use the physical hardware reset button through the opening at the bottom-left corner.

Why is my ecobee Smart Si thermostat not turning on?

The Smart Si receives operating power from the HVAC equipment. If it does not start after installation, the installer should check that equipment power has been restored and that the thermostat wiring follows the appropriate connection diagram. Electrical inspection should be performed by a qualified HVAC technician.

What does Heat Not Responding or Cool Not Responding mean?

Heat Not Responding indicates that the heating system has failed to provide the required heating response. Cool Not Responding indicates that the cooling system has failed to cool the building. These alerts identify HVAC operating problems that may require professional equipment inspection.