Plumbing Kit - Water Filter, Pressure Limiting Valve , Hoses & FittingsCoffee Machine Warehouse has a plumbing kit which includes all the pieces required to plumb your domestic or commercial machine to mains water. Filtration is a key factor for the longevity of your coffee machine and the pressure limiting valve to reduce the pressure from the mains connection to be suitable for your espresso coffee machine. Connect one end to your machine , one end to your mains water connection and you are ready to go! Features and