I'm using fit-pc like a home server for 17 month. I can't recommend to use it for such purposes.
For 24/24 with HDD is to hot so I switched with SSD, anyway can't work more than 6 hours under pressure. Temperature is ~55°C.
Cooling systems it's a problem for such size.

Thank you for the feedback, there are few points worth pointing out.

- HDD temperature of 55°C is slightly higher than average, but not by much. Environmental conditions and system load affect operation temperature. In particular when your usage includes continuous hard disk activity. There are tens of thousands of fit-PC2 units deployed with factory installed hard disks and failure rate is very low, so you may be overly cautious in this case.

- With an SSD installed there is no particular sensitivity to temperature. It can run this way 24/24 (from my experience same applies for factory hard disk, but it is your system and your data so I don't make judgement).

- The fit-PC2 reaches temperature equilibrium much sooner than 6 hours. I am not sure why you picked this number.

- There are several ways to improve thermal behavior of fit-PC2, one of the most popular ones is to attach the external heatsink. See http://www.fit-pc.com/web/fit-pc2/accessories/

Best regards,

On the Load graph you can see when the system hangs.

There are multiple HW and SW issues that can cause the system to hang intermittently. The time scale of hangs makes overheating one of the least likely ones. You can easily test it by warming the fit-PC2 to 5-10C higher than normal (eg by lighting an incandescent light bulb at a proximity). If the problem is heat related then hanging rate should be an order of magnitude more frequent.

Without heat-sink and the same Load level system hangs in 30 min, so the problem is definitely the heat. If I'm installing an active cooler the system works fine. But I want a fan-less system.

I suggest you RMA the fit-PC2 for replacement - rma@fit-pc.com