Hi [NAME],   You can refer to this Environmental specifications guide: [URL]   Non-operational temperature limits: -40 to 65°C (-104 to 149°F)    Hopefully this helps. 
Hi, My name is Emanuel Serrano and y buy a Dell EMC PowerEdge R750xs server. It is beatufull !!!I want to know the preservation temperature ranges (turn-off). This is because it will be stored in a warehouse in which the temperature range can go from -20°C to 40°C.
Preservation temperature ranges PowerEdge R750xs server