Pressure Reducing Valve Failure

[Eternal636]

Hi, hoping to get some guidance from the community—when I tested the water pressure on my Rheem PROG50-38N RH60 hot water heater drain it’s showing 100 PSI—way higher than the recommended range. Pumping the old expansion tank to 60 PSI did not change the reading. So looks like the PRV will have to be replaced (per a plumber’s recommendation--especially since the nut has been cranked down to the bottom). Current setup is closed system with PRV, expansion tank, and 4” vent into chimney stack. (Planning on replacing Rheem with Bradford White RG250H6N since it’s not meeting our hot water needs after reno with body sprays).

The question is whether I replace PRV with a comparable Watts ¾ PRV or if I can go with a cheaper SharkBite PRV1 or PRV2? There are a lot of options and it seems like some are called Pressure Reducing Valves and some are Pressure Regulating Valves—not sure if there’s a difference? One more thing, the copper pipe to the left of the PRV is reduced to ½” then goes back into 3/4” pipe to water heater. Is there a reason that small section is ½” and can/should it be replaced with ¾” all the way through or is it there for a reason? Thank you in advance!!!

 

[breplum]

Pretty much no difference in what you call them.
We only use double union products because it makes it so much easier to swap out.
We always place a new lever handle valve (stainless steel ball) on also.
There are likely some screwy reasons I've seen bantered about for reducing pipe size and until proven differently, are all BS.
Full size piping is ideal.
Sharkbite is a newcomer to the valve business and those linked valves look cheap. I would look at their flow charts to see how their performance matches your maximum house water flow needs.

 

[Bird Doo Head]

You mentioned the screw is all the way in. On a Watts:
In = Higher pressure
Out = Lower pressure

Plan A: With the water off & pressure removed, crank the screw in until it stops & then out all the way a few times.
Sometimes the diaphragm gets stuck and needs a motivator.

Plan B: Rebuild Kit
If it makes your job easier, Watts makes rebuild kits for most of their pressure reducing valves. I've installed lots of them on hydronic & chilled water make up systems. It's not difficult.

After turning off the water and opening a faucet to relieve pressure, take out the screws on the flange. Next, give the dome a gentle tap with a mallet or a piece of wood to break the gasket's seal. The kits come with exploded views, so don't worry if the spring & diaphragm fall out before you get to see the stack order.

Hope This Helps,
Paul

 

[breplum]

I have given up with rebuild kits. I am very precise in following instructions...no boss to care how much time I take...Watts and Zurn...failed to fix the failure.
Hence, the double unions. Really easy if the new one is defective, too.

 

[Twowaxhack]

Your existing PRV is 1/2” and so is some of the piping.

Replace all of that 1/2” and PRV with 3/4” pipe and valves

The recommended flow velocity is exceeded and can cause premature wear when undersized pipe,valves and fittings are used.

 

[Eternal636]

Hello Gentlemen,

Thank you for your feedback. So this is the HD setup I came up with--double union Apollo PRV. One question about the shutoff valve with drain--should the drain be on the right or left side of the shutoff? Pick has it on the left side because I was thinking the sprinkler system is on left for winterizing (but so is heater), so now I'm thinking I have to flip it to have it on right side for servicing of PRV purposes? The drain on the original shutoff is centered so I don't know which side it closes. Any thoughts?