What is the max num of hours a ps3 slim can be turned on ?

well i had a ps3 slim and was broken in six months, the last 3 days i must say i was playing for 10 hours, 2nd day for 8 3rd day for 7 and in the end it coudln't turn on. so they sent me a new one now and i want to know how many hours can stand before it gets broken or overheating. now that i have a new one i want to protect it. so today i played for 6 hours, if i play later at night 2 hours or 3 will overheat??