1- Remove the back cover of the device using the 2.5mm Allen Key provided.
2- Unplug the hoses from the pump head, you might expect some leftover water that was inside the hoses to come out.
3- Remove the pump head by pressing on the two plastic clips on the left and right of it while pulling it upwards to unplug it from its base.
4- Plug in the new pump head and make sure to push it all the way down until you hear a click from both sides of the pump head.This means the pump head has engaged with its base correctly.
5- Plug the tube hoses back to the pump head as they were initially. To be sure that you have the right connections, you should see the hoses crossing each other.