For effective cooling you should be running the wort directly into your fermenter – do not recirculate back into the boiler.

Recirculation is only required for the first 5 minutes of the cooling process to sterilise the inside of the chiller, after this, you can transfer the cool wort out hose to your fermenter as soon as it is cold to the touch.

If you keep recirculating the cooled down wort back into the boiler with wort that's near boiling, you're going to take a very long time to cool the full amount of wort. The counter flow chiller is designed to cool and transfer to your fermenter simultaneously.