New tub/shower set up, not enough water pressure

[alexava]

New here. I hope i get a good easy answer, although i am skeptical. I did residential plumbing, electric, and hvac work 20+ years ago. Automotive worker now. To make a long story short i recently found my bathroom floor weakening and the toilet supply in the wall (cpvc) ( this is Alabama) had a pinhole streaming water for maybe 2-3 years. no visual signs not even a puddle in the crawlspace. Just seepage into the subfloor, joists, beams. My homeowners adjuster denied the claim but that's another story. I have spent the 5-6 weeks building my house (bathroom) back from the blocks up. every thing is new. My house is 25 years old but everything was in great shape. Now it is all new and updated. The tub/shower had to be removed to fix floor. I went back with acrylic tub and tiled the surround and did an awesome job.( i have pics) To my question for the pros. I installed a Delta Windermere Faucet. It works but the pressure is terrible. The old one was fine, the other bathroom on the other side of the wall is fine. This shower stream will not even reach the back of the 60" tub, not close. The instructions with the faucet mentions nothing of a pressure adjustment. I know new regulations limit water pressure/volume but this aint gonna get it. Please tell me i can pull the cartridge out and make a simple adjustment to increase this pressure. I don't want to go through the sheetrock in the hall to remove this thing but i will if i have to.

 

[Terry]

It's the shower head that restricts, not the valve. You can pick up a new shower head, or remove what you have, and drill a small hole in the flow restricter and put it back on.

 

[Sponsor]

 

[Jadnashua]

Well, the valve might have less flow than the old one, but as Terry said, it's more likely the showerhead which is limited by federal codes. Some make it fairly easy to enlarge the opening to increase the flow. Plus, not all showerheads are designed the same...they all have the same maximum flow restrictions, but by changing the size and quantity of the holes, you can get what's left to shoot further.

 

[alexava]

Thx for the replies. I took the shower head off. The rubber washer/ gasket had a very small opening in it. I cut the hole out bigger. That might have helped very slightly but not enough to notice. The screen/ or restricker didnt seem like it would come out. I will take it off and try again. I might try the shower head from the other bathroom. I should have kept the one I took off but did not anticipate this.

 

[JRC3]

If possible I pull the water-saver restricter in every shower head I install in a new shower if I can get to it.

Out of curiosity I would measure the gallons per minute from the shower head, then I'd pull the shower head and see how many you get from the shower arm. If you have a well, do it at the same psi.

Personally, with my current well pressure switch settings, my flow was a little low. I turned up the temp on my water heater and was able to get more mixed water volume...I'm talking like a 20% noticeable difference coming from the shower head. I have a tankless and went from 120 to 140 degrees and am not sure how this would translate to a tanked heater.

 

[Jadnashua]

At specific water pressures, Federal codes limit a single shower head to a maximum of 2.5gpm, and to make sure that they comply, many end up with a lower limit. Then, if your water pressure is on the low side, you tend to get even less. But, how that spray feels, also depends quite a lot on the design of the showerhead...IOW, they are not all created equal.

 

[Gregmech26]

I've read a lot of the newer shower mixing valves and cartridges have significantly lower flow than their old school counterparts. This may contribute to the reason when I bring my own "old school" shower head to some "newly remodeled" hotel rooms that it now makes absolutely *no difference* in increasing shower pressure like it used to because the new mixing valve behind the wall is designed for significantly less gpm than its counterpart of yesteryear.

Wouldn't the "lower flow" contribute to much lower shower pressure coming out of the shower head, regardless if you removed the restrictor in the shower head?

A combination of a high-flow shower mixing valve with high gpm, in addition to an old school "modified" shower head (possibly drilled out) with the water-savers removed, would be ideal in regards to optimizing the highest shower pressure?

 

[Jadnashua]

A shower head has some internal restrictions because of the small holes. But, to maintain the maximum output of the shower head, the sum of the openings in the shower head outlet must be at the minimum, the same as that coming in, or, ideally less. Just like you likely have a fairly big water main feeding your house out at the street, and it can maintain the pressure in your house, but, if everyone was using water at the same time, the main might not be able to supply the desired pressure to all...same with the showerhead. Most 1/2" shower valves can provide in the order of 5-6gpm, and a federally mandated showerhead can't flow more than 2.5gpm...so, it should not matter until the valve got down to about that same 2.5gpm flow rate that you'd notice a difference. The use of CPVC or pex can limit the maximum flow unless it is larger than the copper size piping since the walls are thicker, and thus, the maximum flow is lower. The valves are specified based on nominal copper piping inlets. The OD of copper, pex, and cpvc are all the same, but the wall thickness and thus ID of the plastic pipes is considerably smaller.

 

[Gregmech26]

I think that may be why I get more pressure out of my modified 4-jet Speakman Anystream shower head compared to the 8-jet version.

 

[Jadnashua]

Get a bucket and a stopwatch or something with a second hand, and measure the gpm you are getting out of the head(s). The gpm rating on the valve assumes copper piping of the proper size and a set pressure (I think they usually test a 60psi, but don't quote me on that). Then, the copper institute's copper tubing manual shows the developed friction based on tubing size, effective length (note, that isn't just the length of the pipe - every fitting adds some effective length to it so more fittings, more friction, more pressure drop), and flow rate. Note, with copper, hot water, and a 1/2" copper pipe, the recommendation is <5fpm velocity, and with the ID of that 1/2" copper, that amounts to about 4gpm. When you start to exceed that, the friction increases and the operating pressure starts to drop more rapidly. It also becomes noisier and can , under more extreme conditions, literally wear the pipe out from inside through cavitation.