Tools you need: 

- Drill for mounting anchors (3/16” drill bit) 

- Small flathead screwdriver 

- Phillips screwdriver 

- Wire stripper (optional) 

- Hammer (optional) 

- Pencil (optional)

Step 1:  Power off your HVAC system using the:

1. The master switch   OR    2. The circuit breaker

Step 2: To be on the safe side, ensure that your system is completely switched off. Double-check that:

1. No air is coming out of air vents

2. Main flame is extinguished in case of boiler

Step 3: Go to your already installed thermostat and remove it from the wall.

Step 4: Look closely for any of the following indicators on your old thermostat’s backplate:

If you find any of the above indicators, you should stop right here, as your HVAC system might not be compatible. 

In case of no such indicators, you can continue with the installation.

WARNING: Cielo Smart Thermostat only works with 24V AC. It does not work with line (high) voltage or millivolt systems

Step 5: Grab your smartphone and take a picture of your old thermostat wiring.

Step 6: Take out the C-Wire Adapter (CWA) from the Cielo Smart Thermostat box.

Step 7: Your system should have the following wires to work with the C-Wire Adapter:

Note: If you don't have the required wires, please contact Cielo customer support.

Step 8: Grab the C-Wire Adapter, wire labels, tools, your smartphone, and go to your HVAC system.

Step 9: Take off your HVAC system’s cover to access the control board and take a picture of the connected wires. You may need it at a later stage.

WARNING: Proceed with caution, as HVAC systems contain high-voltage wires. 

Step 10: Label only the following wires with the matching labels: 

Note: In the case of a two-transformer system (wires connected to both RC and RH terminals at the control board), please contact Cielo support to help you with installation. 

Call: +1 (425) 529-5775  Email: sale@cmerweb.com

Step 11: Disconnect the labeled R, Y, G, and W wires from the control board.

Step 12: Securely connect the wires from the control board to their matching terminals on the CWA.

Step 13: Securely connect all the wires coming out of the C-Wire Adapter to the corresponding terminals on the control board of your HVAC system.

Step 14: Place/mount the CWA at a suitable location inside your HVAC system. Close the HVAC cover panel securely and return to your old thermostat.

Step 15:
1. Disconnect the old thermostat wires one by one and mark them using the wire labels (included in the box).

2. Remove the mounting plate of your old thermostat. 

Step 16: Optional: You may use the provided wall plate to hide marks or holes on the wall left by your old thermostat installation.

Step 17:

1. Take out the labeled wires through the hole in the middle of the Cielo Smart Thermostat backplate.

2. Screw in the backplate using the provided pair of drywall anchors and screws.

Step 18: First, connect these 3 wires as shown: 

Then, connect the remaining wires to their corresponding terminals (press terminal block buttons for ease of insertion).

Step 19: Gently push the excess wires back into the center hole of the backplate to ensure that no drafts are coming from the hole.

Step 20: Align your Cielo Smart Thermostat with the backplate and press gently to fix it properly.

Step 21: Go to your HVAC system and turn on the power from the master switch or circuit breaker.

Step 22: Welcome screen is displayed on Cielo Smart Thermostat! Follow the on-screen instructions to set up your thermostat.

All Done! Enjoy your smart home climate control. 

Troubleshooting 

If your Cielo Smart Thermostat doesn’t turn on, please try these steps: 

1. Close your HVAC panel properly, as some systems may not work if the panel isn’t fully closed.

2. Check the backplate wire connections and ensure they are inserted properly into the terminals.

3. In the case of one R-Wire, make sure it is inserted into the RC terminal. 

• R or RC or RH > RC 

In case of more than one R-Wire, make sure RH is inserted into the RH terminal and RC or R is inserted into the RC terminal. 

4. If you installed the C-Wire Adapter, ensure all wires are connected to the correct terminals on your thermostat.

•  R or RC > RC
•  G > C 
•  Y/Y1 > CWA