Why does my fan run constantly at max speed after being replaced?

I recently replaced the fan in my macbook after the original fan had issues with the bearings. After reconnecting everything and turning the computer on the fan runs smoothly.

After using the computer for a couple hours I noticed the fan rpm never dipped below 6000 rpm. No processes were hogging the cpu (verified in Activity Monitor) and iStat displays temperature readings from all the sensors so I doubt I have an issue where the sensor became disconnected (current CPU temp is 113 F and fan speed is at 6000 rpm). I've also reset both SMC and PRAM to no avail.

Are there any steps I can take to make the new replacement fan behave normally?

Thanks!