Thermostat Wiring Configuration and Installation Guide
How to install your Cync Thermostat and wiring configuration information.
Quickly navigate to a specific section by selecting a link below.
Installation
Manual Set Up Without Wi-Fi or Cync App
Wire Labels
Wiring Configurations
PEK Wiring Configurations
Troubleshooting Tips
Installation
Follow the steps outlined in the Cync application or in the Installation Guide that is included with your Cync Smart Thermostat. To confirm your wiring is compatible with the Cync Smart Thermostat use the Cync Thermostat Compatibility Tool.
IMPORTANT:
- Power off your circuit breaker and ensure that all equipment is fully powered off.
- Do not proceed if voltage labels read 110v or 120v, L1 or L2 terminals are present, or high voltage warnings are present.
Manual Setup Without Wi-Fi or Cync App
Setup
Manual set up may be done if there there is no connection to Wi-Fi or Cync App. Before begining, make sure the thermostat is in OFF mode. Follow the steps below:
- Initiate manual setup by pressing and holding the – and + buttons together for 10 seconds. You will see the screen change to manual set up mode.
- Use the – and + buttons to toggle to the desired configuration. To determine your mode code, refer to the Manual Setup Mode Codes section below. To lock in the selection, press and hold the – and + buttons together for 5 seconds or waiting 30 seconds for it to time out.
- Use the Mode button to toggle between 1 or 2 power wires.
- If your wiring includes only one power wire, like Rc, set the power wire to 1.
- If your wiring includes two power wires, like Rc and Rh, set the power wires to 2.
IMPORTANT: Setting the power wires incorrectly may cause damage to the HVAC equipment and/or thermostat.
Manual Setup Mode Codes
| Code | HVAC System | Code | HVAC System |
| 01 | 1 Stage Cooling Conventional | 17 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Cool - Electric Aux |
| 02 | 2 Stage Cooling Conventional | 18 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Cool - Boiler Aux |
| 03 | 1 Stage Heating Conventional - Gas | 19 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Cool - Gas Aux |
| 04 | 1 Stage Heating Conventional - Electric | 20 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Heat - Electric Aux |
| 05 | 2 Stage Heating Conventional - Gas | 21 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Heat - Boiler Aux |
| 06 | 2 Stage Heating Conventional - Electric | 22 | 2 Compressors or 2 Speed Compressor Heat Pump (1-AUX) - On Heat - Gas Aux |
| 07 | 1 Stage Heating/Cooling Conventional - Gas | 23 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Cool - Electric Aux |
| 08 | 1 Stage Heating/Cooling Conventional - Electric | 24 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Cool - Boiler Aux |
| 09 | 2 Stage Heating/Cooling Conventional - Gas | 25 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Cool - Gas Aux |
| 10 | 2 Stage Heating/Cooling Conventional - Electric | 26 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Heat - Electric Aux |
| 11 | 1 Compressor Heat Pump (1-AUX) - On Cool - Electric Aux | 27 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Heat - Boiler Aux |
| 12 | 1 Compressor Heat Pump (1-AUX) - On Cool - Boiler Aux | 28 | 2 Compressors or 2 Speed Compressor Heat Pump (2-AUX) - On Heat - Gas Aux |
| 13 | 1 Compressor Heat Pump (1-AUX) - On Cool - Gas Aux | 29 | 1 Stage Heating Conventional – Boiler |
| 14 | 1 Compressor Heat Pump (1-AUX) - On Heat - Electric Aux | 30 | 2 Stage Heating Conventional – Boiler |
| 15 | 1 Compressor Heat Pump (1-AUX) - On Heat - Boiler Aux | 31 | 1 Stage Heating/Cooling Conventional – Boiler |
| 16 | 1 Compressor Heat Pump (1-AUX) - On Heat - Gas Aux | 32 | 2 Stage Heating/Cooling Conventional - Boiler |
Wire Labels
| Label | Description |
|---|---|
| C | Is the Common wire from your HVAC system that supplies 24VAC to power the thermostat. The wire is typically blue or black. If a Common wire is not present, you will need to install your Cync Smart Thermostat with the included Power Extender Kit (PEK). |
| R | Heating and cooling power wire. It is typically red. If there is only one R wire, (including Rc and Rh) this will be inserted into the Rc terminal on the Cync Smart Thermostat. NOTE: No need for a jumper wire between RC and RH. The thermostat will handle it for you. |
| Rh | In a single transformer HVAC system Rh is the heating and cooling power wire. To supply power to the Cync Thermostat it must be wired to Rc. In a dual transformer HVAC system where there are Rh and Rc power wires, Rh is the power wire connected to the heating transformer. |
| Rc | In a single transformer HVAC system Rc is the heating and cooling power wire. In a dual transformer HVAC system where there are Rh and Rc power wires, Rc is the power wire connected to the heating transformer. |
| W1 | With a conventional HVAC system W1 controls the first stage of heating. With a Heat Pump system W1 controls stage 1 Auxiliary heat. |
| W2 | With a conventional HVAC system W2 controls the second stage of heating. With a Heat Pump system W2 controls stage 2 Auxiliary heat. |
| Y1 | With a conventional HVAC system Y1 controls the first stage of cooling. With a Heat Pump System Y1 controls the first stage of heating and cooling. |
| Y2 | With a conventional HVAC system Y2 controls the second stage of cooling. With a Heat Pump System Y2 controls the second stage of heating and cooling. |
| G or G1 | Controls your HVAC fan. Wire is green. |
| O/B | In a heat pump HVAC system, O/B is used to control the reversing valve which switches your system from heating to cooling and vice versa. Our thermostat does not support separate relays for O and B. Within the Changeover valve setting in the Cync app, choose the correct setting based on the color of your O/B wire. If your O/B wire is blue, choose On Heat. If your O/B wire is Orange, choose On Cool. |
| E | The E wire is for Heat Pump systems and is used to turn the Emergency Heat On/Off. The E wire connects to the W1 terminal of the Cync Thermostat. |
| AUX/AUX1 and AUX2 | Some Heat Pump systems will have two stages of Emergency Heating. Connect the Aux/Aux1 wire to the W1 terminal and the Aux2 wire to the W2 terminal on the Cync Thermostat. |
Wiring Configurations
Review the wiring configurations below for some common wiring scenarios.
NOTES:
- The wiring diagrams below do not demonstrate all possible wiring configurations.
- Wire color seen in the wiring diagrams may not match the wires present in your system.
1 Stage Heat - Gas and Electric
1 Stage Heat, 1 Stage Cool - Gas and Electric
1 Stage Heat, 1 Stage Cool, Separate Power Source
2 Stage Heat, 2 Stage Cool, Separate Power Source
Heat Pump, 1 Stage with Auxiliary Heat
Heat Pump, 2 Stage Heat, 2 Stage Cool with Auxiliary Heat
1 Stage Heat - Boiler
PEK Wiring Configurations
Use the provided Power Extender Kit (PEK) only if no C wire is present.
4-Wire with Power Extender Kit
3-Wire with Power Extender Kit
Troubleshooting Tips
There is an extra wire in the wall after removing the old thermostat.
The extra wire is called the C-wire, and is used to power on the Cync thermostat. Because this wire is present you will not need to use the Power Extender Kit (PEK) during installation. When using the C wire t install your thermostat, before sure it is connected to the C terminal on your furnace.
The C-wire is not present in the wall after removing the old thermostat.
The C-wire is required to power on the Cync thermostat. Because this is not present you will need to use the Power Extender Kit (PEK). See the wiring diagram below on how to install the PEK.
NOTE: No need for a jumper wire between RC and RH. The thermostat will handle it for you. The R wire needs to go into the RC terminal on your thermostat.
My thermostat will not power on following installation.
- Confirm that all wires are properly inserted into the terminal blocks at the thermostat. Tug at the wires to ensure they are firmly in place.
- Make sure the R (power) wire is connected to the RC terminal.
- Ensure the circuit breaker is powered back on.
- Some HVAC equipment feature a safety or locking system that cuts power off if the cover panel isn’t shut properly. Ensure that it is.
- If the Power Extender Kit (PEK) was used, ensure the R wire is connected to RC only. Confirm that the G wire is inserted properly into the terminal.
The thermostat has been connected to a dehumidifier, humidifier or vent but doesn't appear to be working.
The Cync thermostat is not compatible with dehumidifiers, humidifiers and vents.