I have a watts 25aub installed which should be about 6 years old which is the age of the house. I am currently experiencing my prv on my hot water heater leaking at times so in looking into this I discovered that in checking my pressure that I am 120 psi on both sides of the regulator. The adjustment screw is sticking out of the regulator about 1 1/2 to 2 inches already which from what I understand is that you go counter clockwise, loosen, this screw to decrease pressure. A couple of questions:

Can it be adjusted so far out that the mechanism counter acts itself and needs to be adjusted back in for proper function?

How far out does this adjustment screw come out(How much more adjustment room is there)?

Or is this just a bad reguator that needs to be replaced?

Thanks for your help

It's probably a bad regulator. Usually with no pressure on the diaphram by the screw,

The regulator is off. In esscence, you should be able to remove the screw (Counter-clockwise) until no force is felt while turning the screw and you should have 0 output or zero pressure.

The regulator can't be adjusted if both input and output is off. In other words, the water has to have an out (an open valve downstream) that can be opened to relieve a previous setpoint and make it smaller.

The pressure will go up just fine with a closed outlet downstream.