Kernel Log error

[LittleS]

Hi!

I am mining with l3+ machines and quite seldome i will get this error.
Apr  2 01:01:15 (none) local0.notice cgminer[11948]: [TUNER] Timer wait 10800 sec
Apr  2 04:01:15 (none) local0.notice cgminer[11948]: [TIMER] Collecting HR started..
Apr  2 04:02:11 (none) local0.notice cgminer[11948]: [TIMER] CHECK HW started..
Apr  2 07:02:12 (none) local0.notice cgminer[11948]: [TIMER] Collecting HR started..
Apr  2 07:03:08 (none) local0.notice cgminer[11948]: [TIMER] CHECK HW started..

After that the machine will automatically restart and then everything works again.
Can you help me to understand what this means!

Thank you!