serin labsUse this reference to identify the controller's current state before choosing a troubleshooting step. The meaning depends on the installed firmware.
- Button
- The turquoise press surface on top of the controller.
- Indicator windows
- The three openings below the USB-C port let you see the LEDs.
- RGB status LED
- Its color and blink pattern indicate the controller's state. See the status light meanings below.
- Blue Wi-Fi LED
- On when disconnected from Wi-Fi; off when connected.
These LED meanings apply to HomeKit-compatible and Matter-compatible firmware. ESPHome uses different LED behavior.
Enlarge illustration.Status light meanings
On the HomeKit-compatible and Matter-compatible firmware, the RGB LED provides status information. Its color identifies the active function, while its pattern indicates the current state. A slow pulse means the controller is working or waiting. A solid light indicates a steady state or fault. A fast blink indicates that attention is required.
With ESPHome firmware, the LED is a standard Home Assistant light entity. The status
meanings below do not apply.
| Light | What it means |
|---|---|
| Off | The controller is operating normally. |
| White solid | The controller is starting. The light turns off when the web interface is available, usually after about five seconds. |
| White slow pulse | A firmware update is in progress. Do not disconnect power. If the update does not finish, see OTA update fails or the controller does not respond. |
| White fast blink | The identification function is active. The light turns off after three seconds. |
| Blue slow pulse | The setup Wi-Fi network is available and waiting for a connection. On Matter-compatible firmware this is a recovery network; initial pairing uses Bluetooth. |
| Blue fast blink | The controller is connecting with the Wi-Fi credentials you entered. This may take up to 30 seconds. |
| Blue solid | The Wi-Fi connection was lost, and the controller is reconnecting. This applies only to boards without a separate blue Wi-Fi LED. See controller repeatedly disconnects from Wi-Fi. |
| Green solid | Confirmation: the controller connected to Wi-Fi or paired with a Serin Link. The light remains on for a few seconds. |
| Red solid | The indoor unit is not responding over the CN105 connection. See CN105 is connected, but no data appears. |
| Red fast blink, then stops | The most recent action failed. The Wi-Fi credentials may be incorrect, or Serin Link pairing was unsuccessful. |
| Red fast blink, continuous | The indoor unit is reporting an error code. The web interface displays the code. |
| Yellow slow pulse | The controller entered safe mode after repeated crashes. See the light is pulsing yellow. |
| Purple slow pulse | A Serin Link pairing window is open. |
| Orange fast blink | The paired Serin Link was removed. The controller restarts immediately. |
| Cyan slow pulse | The controller is ready for pairing and has not yet been added to an account (Matter-compatible firmware). |
| Cyan fast blink | A pairing process is in progress (Matter-compatible firmware). |
The controller displays one status signal at a time. Setup signals take priority, so a fault may appear only after setup is complete. Holding the board button overrides the current signal.
A separate blue LED indicates Wi-Fi status on the M5Stack NanoC6. Lit means disconnected, and off means connected. On this board, the RGB LED does not use blue to indicate a lost Wi-Fi connection.
Button hold actions
These actions apply to HomeKit-compatible and Matter-compatible firmware. For Wi-Fi changes and full resets, follow the maintenance guide. ESPHome does not use these button actions.
The light changes as you hold the button. Pairing actions happen when you release it; the Wi-Fi reset happens while you are still holding it at 10 seconds.
| Hold time | Light | Action |
|---|---|---|
| 2 to 7 seconds | Purple solid | Release to open a Serin Link pairing window or remove the current pairing. |
| 7 to 10 seconds | Red fast blink | No action. Release the button during this interval to cancel. |
| 10 seconds | Red fast blink | Erases the stored Wi-Fi credentials and restarts immediately, while the button is still pressed. |
On boards with a button but no RGB LED, the same press durations apply, but no visual indicator is available.