How warm should the SH2 get?
it can get quite warm to the touch but a lot will depend on where you have it sited and if there is good ventilation round the hub
IT equipment does tend to run very warm, especially Wi-Fi.
We had a rule of thumb when I was in the industry...if it's too hot to keep your hand on it continuously then it's too hot.
If you have any real doubts, though, it might be better to shut it down to be safe.