Pressure protection valves should be fitted if your water pressure is likely to exceed 100psi at any time (this sometimes happens over night on mains systems). The valve will protect your filter and give you peace of mind.
Modern water pressures can fluctuate at different times, and as such we supply a pressure protection valve as standard with all new Under Counter filter kits (UC12, UC40 and UC60 complete models ).
The pressure protection valve fits into the cold water line supplying water to the filter to protect your filter from pressure surges up to 150psi. Fitting of a pressure protection valve is good plumbing practice.