Low Pressure.... What did I do wrong with my Delta Shower Setup? (2024)

09-14-17, 06:29 PM

Plumbing Pros (or DIYers),

I recently completed a renovation to a new bathroom shower that has two shower heads - one "normal" wall one and another hand shower on a holder. I ran 3/4" PEX up to the bathroom zone, then teed off to the hot and cold shower feeds with 1/2" PEX. I opened up the 1/2 PEX runs and confirmed that EACH side (cold and hot) were delivering well over 6 gallons of water per minute.... PLENTY I figured for two heads that would each probably draw max 2 GPM each.. right?

We'll I hooked up a Delta R10000-UNBX rough valve to control water, then above that a 3 position diverted... hand, top, or both. Everything works as expected, but when I have BOTH running pressure is noticeably less.. One or the other is fine.. just not both running at the same time.. SO... what did I do wrong? I NOW know that there is a higher pressure valve that Delta makes, but is that the answer from the start? I have a normal "14" trim kit installed... would upgrading to a "17" add more flow? Is there a new cartridge only or something I can DO to the existing cartridge to improve flow?

Any ideas? I don't have access to the valve body anymore.. behind tile from one side and studs from the other.. no no way to change out the rough valve.. just want to increase pressure.

Thanks in advance!

Jay

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09-14-17, 07:38 PM

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09-15-17, 07:05 AM

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09-15-17, 01:22 PM

Thanks to you both! It's sort of a bummer that Delta has that reducer in there.. I know everyone's trying to be more green nowadays, but showers (especially multi-head) need pressure!

SDPlumber - to answer your question, I plumbed between heads and diverter with 1/2" pex.. (attached is a photo for reference). I know that's less than 1/2" copper in terms of flow, but as I mentioned.. before I hooked up any Delta anything I did the usually recommended "bucket" test and was able to fill up a 5 gallon bucket in about 50 seconds... with the cold side and the same thing from the hot side... so flow through 1/2" pex (at least to the first valve) I know is very strong.

I saw a youtube video where I guy took a drill and manually drilled out that little reducer tube that czizzi mentioned I think:

https://www.youtube.com/watch?v=NHH_yD_OQZw

(jump to 2:20 if you want to speed it up)

That seems a little drastic, but maybe might be a solution since it's already in the wall and inaccessible?

I also hear what you're saying with the diverter.. The diverter's 3 holes are really pretty small, but part of the cartridge is a ceramic disk thing that I don't think I would be able to drill (even if I was that brave). Does Delta make higher flow diverter cartridges or something?

Thanks again!

Jay

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09-15-17, 01:40 PM

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09-15-17, 01:55 PM

Thanks SD... forgot to mention I think my pressure is fine.. it's a big old house.. in the basem*nt I have 80PSI and the main coming in from the street is 1.25".. I have an old tub on the 3RD floor (this problem above is on the 2nd floor) that I plumbed with 1/2" PEX and there is PLENTY of pressure.. So I really think it's down to the valves.. but I guess I'm stuck if there isn't a new drop in cartridge (unless I want to get daring!).

It DOES work, it's just not really that strong with both going at all. Either ONE is pretty tolerable.. I'm just a bit peeves cause I did all the nice tile work and everything myself... wanted it to be a show-stopper bathroom - which it pretty much is.. unless you shower in it

Thanks again..
Jay

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09-15-17, 05:53 PM

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