3-way Shower diverter with limit of one function at a time?

lwernerAugust 11, 2012

In my new house I'm thinking of equipping the master bath with a hand shower, overhead rain shower, and body sprays. I know I need a 3-way diverter for that, and I was thinking of Hansgrohe's "quattro" model, though I'm not wedded to that brand.

Now I've realized that I have to follow the CalGreen restrictions where the total flow of all shower fixtures that can be activated at one time must be less than 2.5 gpm. Since the Quatto and other diverters I've seen allow two functions to be activated at a time, that means I'd need to keep all three fixtures below 1.25 gpm each, which makes the sprays and rain shower pointless and the hand shower not much better.

I could get around this if I had a 3-way diverter that allowed only one of the outlets to be active at once. That way I'd have to keep each individual fixture below 2.5 but not have to worry about how they add up. (I know a rain shower at 2.5 gpm is also pretty marginal, but I figure I can always switch to a less restricted head later if it annoys me too much.)

Does anyone know of a 3-way diverter that's restricted to one output at a time? Bonus points if that's enforced by a stop ring that I can rip out later. :-)



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I don't know squat about plumbing. I would set it up so it can pass code check, but leave it easily accessible for conversion once you are moved in...maybe do a 2 way for now and add the third fixture later, and change the diverter later? Of course I have no idea if that is possible but it seems silly to put all three at 2.5 total gpm or just go with the diverter you are looking for if you can find it, but what fun will that be!?

    Bookmark   August 25, 2012 at 4:32PM
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Actually, CalGreen restricts the total flow of all shower fixtures to 2.0 gpm, not 2.5 gpm.

    Bookmark   August 27, 2012 at 3:41PM
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I left out some details that I shouldn't have. I'm following the so-called "performance path" of CalGreen that lets you exceed the "prescriptive" 20% reduction" requirement on individual fixtures as long as you achieve an overall 20% reduction across the whole house. Since I'm building in Mountain View, I'm using the spreadsheet in section 4.303 of the "Mountain View Amendments to 2010 CalGreen". They list the baseline number for showers as 2.5.

I believe (and correct me if I'm wrong) that by using really low-flow toilets and faucets throughout the house, plus very low-flow showerheads in the other 2 bathrooms, I can use more than the "prescriptive" number on the master bath shower as long as the total water usage comes in with at least 20% savings. The code section I referenced above describes how to do the calculations, giving values for number of minutes or flushes per day, number of occupants based on number of bedrooms, etc. I put it all into a spreadsheet so I could tweak the numbers. I can post a link to that if you're curious.

The summary is that I think I can go up to 2.5 gpm in the master shower, which means a 2.5 gpm hand shower and overhead rain shower, plus 3x 0.8 gpm body sprays, as long as only one of those can operate at any given time.

I have absolutely no experience with this, though. If you or anyone else has actually done this sort of thing and know what inspectors tend to allow and forbid, I'd love to hear from you. And as soon as I pick a contractor (next week I hope) I'm going to find out who his plumber is and ask the plumber about it.



    Bookmark   August 27, 2012 at 5:35PM
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I suggest going to a local dealer/showroom to get proper advice and solutions for your area.

    Bookmark   August 29, 2012 at 9:33AM
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