Connect your Serin Controller to Wi-Fi and add it to Home Assistant using ESPHome firmware.

Different firmware? Choose your guide.

On this page

Continue an existing setup

Keep the firmware you installed. Start at the first task you have left:

• Not installed in the indoor unit yet? Install it in the indoor unit.
• Installed, but not on Wi-Fi? Join your home network.
• Wi-Fi connected, but not paired? Add your controller to your app.
• Already paired and installed? Check that the unit responds.

Before you start

• A compatible indoor unit and controller with this guide's firmware installed. If you have not flashed it yet, use the flash tool on a computer with a USB-C data cable.
• A 2.4 GHz home Wi-Fi network and its password.
• Home Assistant and the ESPHome dashboard (available as the ESPHome add-on).

1 Install the controller

Follow the installation guide to connect the CN105 cable, position the controller, and replace the cover before restoring power.

Before moving on: The cover is back on and power is restored. If you paired before installation, check that the controller reconnects to your home network.

2 Join your home Wi-Fi

Already connected in the flash tool? Continue to app setup.

1. On your phone, join serin-XXXXXX, using the password serinlabs. The suffix is unique to your controller.
2. The setup page opens. If it does not, browse to http://192.168.4.1 while still connected to the controller's setup network.
3. Enter your home Wi-Fi name and password. The controller saves them and restarts on your network.
4. Reconnect your phone to the home network. Check the router's connected-device list if you need the controller's IP address.

Check: Your phone is back on home Wi-Fi and the controller appears in your router's connected-device list.

Another way to join Wi-Fi, or a missing setup network

You can also enter the controller’s Wi-Fi details from a computer over USB using the flash tool's Wi-Fi option. You do not need to reinstall firmware just to change the network. If the setup network does not appear, use Wi-Fi troubleshooting.

3 Add to Home Assistant

Already adopted and added to Home Assistant? Check control.

1. Open the ESPHome dashboard in Home Assistant. With the add-on installation, it is under Settings → Add-ons → ESPHome.
2. Find the controller's Discovered tile and select Adopt. Give it a name such as living-room.
3. Select Install to build and send the personalized configuration over Wi-Fi. The first build takes a few minutes.
4. In Home Assistant, open Settings → Devices & services and configure the discovered ESPHome integration. If you already added it during flashing, use that existing integration.

Discovery requires the controller and Home Assistant to be reachable on the same local network with mDNS allowed. If no device appears, see ESPHome discovery troubleshooting.

The browser-installed build has a standard configuration. After adoption, use Customize ESPHome to add optional diagnostics, a room sensor, or other supported features while preserving the device's credentials.

Check: The controller appears as a thermostat in your app. Next, check its connection to the indoor unit.

4 Check that the unit responds

1. Open the thermostat in your app and check that it reports the room temperature.
2. Change the mode or target temperature and confirm the indoor unit responds. Check that the app and controller report the resulting state.
3. If the app is connected but commands have no effect, use the CN105 checks. App pairing alone does not prove the cable's data connection works.

Setup is complete when the app shows a current room temperature and the indoor unit responds to your commands.

Once control works, use the web interface for additional controls, or follow the room sensor, update, and Wi-Fi and reset guides. For another indoor unit, repeat the process with its own controller and a unique name.