How to install the PSU

[songorocosongo]

My brother bought an 650w Ultra PSU from CompUSA and he is installing it on his HP Pavilion Elite. We are already there but we are not sure on the direction because of the fan. The computer only has on exhaust fan on the back and that's it. No other fans. So how should he place the PSU? It goes mounted on the top. Fan pointing to the inside or to the outside?

This is the PSU http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=3276573&CatId=1483

 

[songorocosongo]

Don't bother. Already decided to mount it facing up