HVAC / Thermostats & Controls
Installation and User Guide for Ecobee Smart Thermostat LITE
Comprehensive installation and configuration guide for the Ecobee Smart Thermostat LITE. Includes wiring diagrams for conventional, heat pump, and fan coil systems, terminal descriptions, and detailed threshold settings.
Quick answers from the manual
Quick answer
- The Ecobee Smart Thermostat LITE is a 24VAC thermostat compatible with most residential HVAC systems. This manual provides wiring diagrams for various configurations and instructions for configuring system thresholds and equipment settings. p. 1
Key actions
- Turn off power to the HVAC system p. 1
- Install PEK if no common wire p. 1
Problems and fixes
No common wire
Use Power Extender Kit (PEK).
p. 1Technical specifications
| Parameter | Value | Meaning | Pages |
|---|---|---|---|
| Voltage | 24VAC | Operating voltage | p. 1 |
| Current Limit | 2A | Maximum current per terminal | p. 1 |
Where to find it in the PDF
- Wiring Diagrams and Installation p. 1
- Configuration Settings p. 1
Table of contents
Quick guide from the manual
The Ecobee Smart Thermostat LITE is designed for 24VAC residential heating and cooling systems. Warning: Do not connect to line (high) voltage or millivolt systems. Limit current to 2A maximum per terminal. Always turn off power at the master switch or circuit breaker before installation.
System Compatibility
The thermostat supports:
- Heating: Up to 2 stages.
- Cooling: Up to 2 stages.
- Heat pumps: Air, water, and geothermal with up to 2 stages, plus 2 stages of AUX heat.
- Accessories: Dehumidifier, humidifier, or ventilation device.
- Fan coil units: 2- and 4-Pipe with up to 3 fan speeds.
- Packaged Terminal Air Conditioners (PTAC): Up to 3 fan speeds.
Terminal Descriptions
- G: Fan.
- Rc: Cool transformer or single transformer setup.
- Rh: Heat transformer.
- O/B: Heat pump reversing valve.
- Y1, Y2: Used for 1-2 stages of conventional A/C or heat pump compressor.
- W1, W2: Used for 1-2 stages of conventional heat or auxiliary heat with heat pump.
- C: 24VAC common.
- ACC: Used for 1-wire dehumidifiers, humidifiers, ventilators, HRVs, or ERVs.
Installation and Wiring
If you do not have a C-wire (common wire), the Power Extender Kit (PEK) can be used to extend a C-wire. Note that the PEK is not compatible with dual transformer, fan coil, or communicating units. Refer to the specific wiring diagrams provided in the manual for your system type (Conventional, Heat Pump, PTAC, or Fan Coil).
Configuration Settings
The thermostat allows for detailed customization via the Installation Settings menu:
- Threshold Settings: Configure Auto Heat/Cool, Compressor Min Cycle Off Time, Heat/Cool Min Delta, and staging options.
- Equipment Settings: Manage settings for humidifiers (Evaporative or Steam), dehumidifiers, and ventilators (including Pre-Occupancy Purge and Free Cooling).
- Reminders & Alerts: Set maintenance intervals for HVAC, furnace filters, UV lamps, and temperature/humidity alerts.
Practical help
Common problems
No common wire available
Use the Power Extender Kit (PEK) to extend a C-wire. Note: PEK is not compatible with dual transformer, fan coil, or communicating units.
Thermostat not powering on
Ensure the HVAC system power is turned on at the master switch or circuit breaker. Verify the system is 24VAC.
Inaccurate sensor reading
Use the Temperature Correction or Humidity Correction settings in the Thresholds menu to adjust the reading.
Before use
- Turn off power to the HVAC system at the master switch or circuit breaker.
- Verify your system is 24VAC (do not connect to line voltage).
- Identify your HVAC system type (Conventional, Heat Pump, PTAC, Fan Coil).
- Check if you have a C-wire; if not, ensure you have a PEK.
- Ensure the current draw does not exceed 2A per terminal.
Model compatibility
- Compatible with most residential heating and cooling systems.
- Heating/Cooling: Up to 2 stages.
- Heat pumps: Up to 2 stages + 2 stages AUX heat.
- PEK not compatible with dual transformer, fan coil, or communicating units.
Manual page author
David Miller
Documentation analyst
Organizes user manual content into clear summaries, with attention to model details, product context, and everyday usability.