Serin Controller installation

Use an assembled CN105-to-Grove cable. If you are making your own, check it against the wiring reference before installation.

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1 Prepare for installation

Confirm model compatibility and that the CN105 port is available.
Install your chosen firmware over USB before fitting the controller. Disconnect the USB cable afterward.
Have a screwdriver ready and read the installation precautions.

2 Connect and position the controller

Connect the indoor unit's CN105 port to the Serin Controller's Grove port with the supplied cable. The cable carries power and communication. Disconnect USB before connecting CN105. — **Port locations vary by indoor unit.** Identify connectors by their labels.

With power off, open the indoor unit's cover and locate the main control board. Find the five-pin connector labeled CN105, usually red and sometimes white. Do not substitute CN110.
Seat the cable's CN105 connector in the unit and the Grove connector in the controller. Check orientation against the connector and board markings; do not force either connector. See the wiring reference.
Position the controller and cable clear of the fan, heat exchanger fins, and condensate tray. Ensure the cover will not pinch the cable.

Close-up of the red five-pin socket labeled CN105 on the indoor unit control board — **Indoor-unit end:** the labeled CN105 socket. Enlarge port photo.

NanoC6 controller with the Grove connector seated at the rear and the free five-pin CN105 connector at the other end of the orange cable — **Controller end:** Grove plug seated in a NanoC6. Enlarge connector photo.

Orange CN105 cable routed beside the indoor unit's control-board enclosure — **Cable routing example.** Enlarge installation photo.

A sheet-metal air-handler cabinet can weaken Wi-Fi. If reception is poor, see placement and Wi-Fi troubleshooting and the cable length options.

3 Replace the cover and restore power

Check the connectors and cable clearance, reinstall the cover, then restore power at the breaker. CN105 powers the controller; leave USB disconnected.

On HomeKit-compatible and Matter-compatible firmware, the status light shows startup and connection state.

ESPHome uses the RGB LED as a controllable light entity, so HomeKit-compatible and Matter-compatible status colors do not apply.

Continue with your platform

If Wi-Fi and app pairing are already complete, go straight to your platform guide's control check.