Is my PSU fan intake or exhaust

Solution
Most PSUs suck aiir in from the bottom and exhaust it out the back of the PC. The Seasonic has it's fan on the bottom, sucks air in thru the bottom of the case (where's there is usually a filter) and exhausts it out the rear of the case.
99.99% of PSU's are exhaust, I'm pretty sure yours is same. (you could verify it by trying to cover the outlet with something light, like bit of paper and see if it sticks to the outlet or is blown away)

edit: That is to say, the fan is exhaust, but since it is pointing to inside of case, it's really drawing in air from the outside and pushing it inside.

Edit2: ... Disregard what I've said above, except the test it yourself part, Looking at my own PSU's it seems nothing is certain.