The maximum water pressure we recommend is 3.4 BAR pressure. Anything higher than this can cause damage to the components. The connections and pipework at the rear it not designed to withstand prolonged use at a pressure higher than 3.4 BAR. Think of it like red-lining your car. If you drive at a low gear and high speed the accelerator meter goes to 8000rpm and above the red-line. This is not good for the car but won’t cause too much damage if it is done once or twice. However, if you did this every time you drove the car would have a failure and it is the same principle when it comes to your shower.