Preferred shower rough-in valves

[Rafalc]

Getting ready to start on the shower and have been doing a lot of research on rough-in valves. Don't need anything fancy, just 1 out for the shower, no stops since I'll have shut-off valves down the line. Dependability and durability is what I am after.

Local plumbing supply stores swear by Moen. I'm considering the Moen 2520.
Thoughts?
Standard vs. Commercial? (not much of a price difference)

Thanks!

 

[Jadnashua]

I don't know if they've changed things, but if you scan through the forum, you'll find that more than a few people have difficulty getting their old Moen cartridges out when it comes time to change them.

I've had good luck with Delta and Grohe, but my sample is small. One thing I like about the Delta R10000 rough-in body is that it gives you a huge choice of not only style, but functionality that you're not locked into. For example, there are three general classes of shower valve:
- single-handle pressure balance
- two-handle volume, temp
- two-handle thermostatic (volume, temp)

Down the line, since the Delta rough-in valve is compatible with all three types, you could switch the functionality by buying a new trim kit (which contains the cartridge). Personally, I prefer a thermostatically controlled valve. I put a short article in the tutorial section that describes my thoughts more.

 

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[Rafalc]

I think I'm going to go with the Moen 3570 based on multiple recommendations. Sad to see all these "features" on these valves introducing new points of failure and for what? I miss the good basic technology and when people had to use common sense in order not to get burnt....

 

[Terry]

The Moentrol is a nice valve. I've installed many of the Moentrol, the Posi-Temp and the old Chateau Moen valves.

 

[Rafalc]

The Moentrol is a nice valve. I've installed many of the Moentrol, the Posi-Temp and the old Chateau Moen valves.

I noticed that the bottom outlet (tub) has a much larger opening (or rather 2 openings) and the top (shower) has 1 small one. I only plan on having a shower so will be capping off the extra out. I read some connect the shower to the bottom out for increased water pressure. Any truth in that? Why would the bottom have an extra opening?

 

[Terry]

The large hole comes from the cartridge, water going down, and then the small hole top and bottom is for the shower head.
Water goes down to the tub spout and either diverts upward to the shower head, or it's capped off and forced up to the shower head through those small holes.

 

[Jadnashua]

The pressure will be the same regardless of the size of the opening. The volume available will be lower on the smaller opening, but, unless you are using more than one head, it is more than sufficient because all shower heads are flow restricted. Some of the valve bodies can be rotated 180-degrees, and that would be required if you were using multiple heads or sprays...that would put the larger opening pointing up so you don't have to deal with more complex piping. Pressure is the same whether you have a soda straw sized pipe or a fire hose...the fire hose can flow lots more water. Irrelevant if there is a restriction, and more isn't able to be used at the outlet. Think finger over the end of your hose...the actual pressure is the same...restricting the outlet increases the velocity, not the pressure, same as the small holes in the shower head.

 

[Rafalc]

The large hole comes from the cartridge, water going down, and then the small hole top and bottom is for the shower head.
Water goes down to the tub spout and either diverts upward to the shower head, or it's capped off and forced up to the shower head through those small holes.

Thanks for the explanation. With that said, if I cap off the top outlet and use the bottom outlet for a shower....would the larger hole give me more pressure out the shower head since it would let more water through?

Looks like I asked at the same time jadnashua replied. I dislike those flow restrictors in the showerheads...I was hoping more water flowing up will somehow battle the showerhead restrictions.

 

[Terry]

Using the larger port at the bottom does allow more volume of water to reach the shower head. I have also "tuned" a shower head by drilling the flow restrictor to a larger size. But you didn't read that here.

 

[Jadnashua]

The size of the opening is more than adequate to provide as much as a code compliant shower head can output, letting it function as designed. If you modify things, it may not be, so more volume can help. Again, seems you are confusing volume with pressure. A bigger outlet in the valve will allow more volume, but won't affect pressure on the line. The only time volume is an issue is if the outlet is larger than the supply. When that happens, you won't get the velocity increase as it goes through the shower head's restriction jets. You can see this with say a garden sprayer. As you open the valve, the spray starts to go further until at some point, it remains the same, regardless of how much more you open the valve...you've reached the maximum flow allowed by the openings of the outlet.

The water pipe in the street has the same pressure as the line going to your house...it's just that it is much larger in diameter and can flow more volume without friction overcoming its natural flow. That doesn't mean your house has less pressure than at the street in the main line.

You want your supply to be at least the volume as the outlet, preferably slightly more. With a stock shower head, the normal outlet of the valve is going to provide that. Change something, then it becomes questionable and more volume may be useful.

Modifying your shower head to allow higher flow also means depleting your WH volume quicker, if that's a factor to you.

 

[WorthFlorida]

To meet the latest energy requirements, manufacturers design the flow requirements into the cartridge design and they cannot be modified. As stated above a larger hole may make the shower head not put out a good spray. The water may just pour out and provide little or no spray. Try this, remove a shower head and turn on the water. Notice that it does not flow out as strong as you might expect. This will prove what Jim explained above with the garden spray nozzle.

During the 1990’s when the first energy bill was past for water usage requirements, most manufacturers put in flow restrictors that we all hated. In the last year I remodeled two bathrooms in my home and installed Delta TempAssure bath/shower faucets. They work quite well with no changes.