Hub 3 red light

The red light on my Hub 3 is constantly on, but the router is not hot to the touch.

I have turned the router off at the mains and restarted it, and also did the pin reset to factory settings - all to no avail. I ran the network diagnostics tool which reported the temperature of the router as normal.

I understand from other posts in the forum that a constant red light usually means the router needs replacing?