The fan should blow air through the heatsink and ideally be blowing to the exhaust fan/area on the rear of the case.
If you need to reseat it make sure the pushpins are correctly inserted as once they've been used the white plastic bottom of the pushpin clip can splay. I had to take the motherboard out of mine to be sure it was fitted correctly. You'll soon know if it isn't as the temperature will shoot up to over 70ºC in a very short space of time or the thermal control will shut the PC down.
I was never impressed with mine and quickly replaced it for one with a decent mounting system.