Pretty much all the units are spec’d at 100 psi from the factory due to using Pex pipe.I use a regulator which has a range of 40 to 55 ft lbs,I don’t trust going any higher,,better to be safe than have a line come apart in the basement compartment.The higher the water pressure.. the chances the pex crimps will leak if not crimped properly from the factory and we will not go there with that issue.........