I installed a CPU cooler yesterday which for me is quite a feat.

The cooler is a Cooler Master Seidon 120xl which comes with two 120mm fans that go either side of the radiator. 

After I installed it and powered up my PC I noticed the CPU temp was exactly the same as it was before the install around 40-45C when idle.

Both fans are working and the cooler itself has the blue indicator light lit up.

So somewhere along the way I've mucked up and the instructions that came with it are no help.

I had a thought that I could have the fan airflow directions wrong. The radiator is sandwiched between them and attached to the back of the case. The only other fans are the ones that came with the case at the front. 

I've got the airflow so that one fan is taking air from outside the case and blowing it onto the radiator. The other is taking air from inside the case and also blowing it on to the radiator. 

Have I got this right? If so, any other theories why the temp is still the same? This is most likely a n00b query but I'm sure a few of you will know where I've gone wrong.