My house's PRV is finally on it's last gallons.
Water pressure is fluctuating in-house.
Valve makes pulsing noises when nearby outside spicot is open and water coming out pulses also.
Also leaking around cap.
I have dug out around valve to facilitate unscrewing from water main.
I am trying to identify type/size so I can have replacement in hand. I believe the PRV below will work,
Watts LFN45B Copper 1/2-in Pressure Reducing Valve

But I am trying to identify old one.
Pictures attached,

 

Most "main" PRV valves are 3/4". It's hard to tell from the picture what size yours is.

 

I Googled Pressure Reducing Valve and the Number/Letters on side...I think it reads 0715S...no luck finding what is installed.

 

Why don’t you measure the O.D. of the pipe connecting to the valve.

3/4” Copper pipe O.D. = 7/8 ….. 1” Copper pipe O.D. = 1 1/8

3/4” Steel or PVC pipe O.D. = 1.050…… 1” Steel or PVC pipe O.D. = 1.315

 

I just measured around the threads on house side of PRV and read 5 inches.
5 inches divided by Pi equaled 1.59.
Does this help?

 

 

Oh well, I'll just get a 3/4 inch and a 1 inch Watts PRV and see what fits.
Is Watts a good PRV?

 

That looks a little complicated there to me anyway, but probably not to a plumber. I think those two nuts mean it’s a double union. I take it that the PVC is the street side. That gray pipe (arrow) I think would represent the actual pipe size if you measure there. I think the other stuff is adapters.

That looks like it would be 3/4.

The PVC pipe looks bigger than 3/4. I don’t understand what the connection is at the PVC side. Maybe it’s some kind of reducer 1” to 3/4.

Do you have a way to shut off the water yourself? As far as I know Watts makes good stuff. I don’t think you should have to buy 2 PRV’s.

If that gray pipe is PEX I'm pretty sure they use the same size as copper.