This thread serves several purposes, actually, so it isn't merely a ploy by a usurping ungrateful grifter trying to snarf up free advice. No doubt others have encountered this very same predicament and very same PRV arrangement. This thread can also be beneficial to them in working their way through it. So, in that sense, it's a chronicle of sorts, communally free to any and all.
I clearly am no expert and I don't think I would ever refer to myself as handy. I do engage in DIY projects, but I also understand I have limitations and when confronted with a project, I consider the cost-benefit of DIY versus farming it out to a professional. This project is on the border of that cost-benefit decision and could go either way considering my limitations. Whichever way it goes, I will still chronicle it so others can benefit from it in the future.
That being said, there is no one way to successfully complete this project. As the commentary underscores, there are many ways to tackle this and the project can vary in scope. For example, at least related to scope, the decision to swap out the inferior gated shutoff valving or not. Whether or not to reconfigure the piping complex and new PRV placement so next time it's an easy swap out is yet another scope decision. Whether or not to sweat and solder versus using Shark Bite fittings is a methodology question. Whether to cut the old unit out versus cutting the pipe on either side of the PRV to remove the old Watts PRV is a question of tactics and methods.
The point is, there is not one answer to this. There are many answers and many ways, some better than others.
As far as experience is concerned, experience has its place but saying you or someone has experience doesn't bequeath you or that person with infallibility or superior status. Here's an example. These fellas are plumbers and have not only experience, but professional credentialed experience that can be readily verified. They claim a PRV isn't even necessary. Following the logic that those with experience are infallible, they must be correct, right? Wrong.
https://www.inhouseplumbingcompany.com/2019/03/13/do-you-need-a-water-pressure-reducing-valve/
Most of the calls we get asking about this valve are for houses 10 to 25 years old and sometimes older.
Our stance: If a home that is 10, 15, or 20+ years old didn’t need the valve before, why is it suddenly a problem? There haven’t been any part failures or flooding because of the water pressure so it’s extremely unlikely the valve is now a necessity. Of course, there are always exceptions but for the majority of the cases, the valve is unnecessary.
But we didn’t stop there. My master plumber, Bill Hoyle, and I went to a trade show a few years ago to talk to plumbing fixture manufacturers. We wanted to know if this was an issue we weren’t understanding, and if so, should we change our stance on it?
We learned two things. One, most of the manufacturers had no idea what we were even talking about when we asked about the the pressure reducing valve. So how can these valves be that important if the manufacturers have never even heard of it?
And two, all the manufacturers test their fixtures from 150 to 200 psi. Meaning, these devices — faucets, toilets, water heaters, etc. — are made to handle a psi from 150 to 200, and homeowners are being made to worry about 80 psi.
Also, I stand my ground on the terminology issue. The main shutoff valve is not the exclusive domain of the PRV, despite the PRV being a fixture, and therefore it is a misnomer to refer to it as the PRV valve. That's misleading and unnecessarily confusing. The main feeds every fixture in the house and not just the PRV. The PRV merely happens to be the first fixture the main encounters.
