Kohler Tresham K-3950 toilet, Reviews, Pictures and Comments

Kohler has a new, "traditional look" toilet with WaterSense labeling.
The Tresham K-3950 with 1.28 GPF, with comfort height and elongated bowl.
I installed one in a 1920's Seattle home to see how it works and looks. The homeowners (Sue's sister) will be reporting back on how it's working for them.

http://www.terrylove.com/wc/kohler/tresham_cindy1.jpg

Kohler Tresham K-3950

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Front end view

http://www.terrylove.com/wc/kohler/t...side_tank1.jpg

Looking inside the tank of the Tresham.

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The trapway of the Tresham

A few more pictures of the Kohler Tresham toilet

http://www.terrylove.com/wc/kohler/tresham_love_1.jpg

Looking at the underside of the Tresham bowl.

http://www.terrylove.com/wc/kohler/tresham_love_4.jpg

The bottom outlet of the Tresham flush valve.

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Top of the bowl

http://www.terrylove.com/wc/kohler/tresham_love_10.jpg

With water in the bowl.

Hmmm, not a 3" flush valve. Though anything new would have one.

Well, Terry, it looks very nice and very solid.

Just like my unuseable Portrait with the unconscionable Ingenium Flush did.

So...pray tell...how does it flush with its 2" canister and its non-dual-siphon trapway?

My own feeling is that Kohler makes some very beautiful china, but I have yet to encounter one that works as well as my Drake. And there is beauty in performance.

(EDIT: Don't mean to sound crabby; actually, I am curious what you think of the flush. Just anytime someone uses "Kohler" and "Toilet" together in a sentence, it's like tossing raw meat in front of a starving wolf. I will never shake off that Portrait experience, and I frankly resent Kohler for making a corporate decision to sell that thing when all they had to do was use it to know that it was total garbage. Shame on them. Accordingly, I will never install a Kohler toilet again, even if they gave me one for free. Because they don't deserve my business, especially when there are vendors who never wreaked that kind of havoc on unsuspecting consumers.)

I also think that the Traditional Look Soiree is much more aesthetically-pleasing.

The style of the toilet is interesting. I guess it's supposed to look "old" but it looks like someones modern take on an older style. (not really old at all), but that's beside the point. I wanna know how it flushes! Looking at the bowl design and shape of the trapway it couldn't be as bad as the "Ingenium" system used to be, that had a far more constricted trapway and tighter turns. This trapway shape looks good except for the tight turn at the exit on the bottom. and I wonder why they couldn't do a 3" flush valve?

Stuff doesn't like instantaneous changes in direction - it slows things down, and they can get caught. A 3" flush valve can release more water, faster than a 2" (obvious), but it is the overall design of the pathway(s) it follows that ultimately determines how well it flushes. Well, execution of the design makes a big difference, too. Toto is somewhat unique in the industry in that it uses a much drier clay mixture when forming a toilet. This creates greater consistency in sample to sample, and reduces slump, twist, and other distortions as it dries. A good design where the pathways have distorted doesn't work well. Why Kohler thinks things will turn a sharp 90 well, I don't know. Maybe they went to a different school than I.

Even though it's a new model, this toilet is listed on the MaP website. It has a 1000g map rating.

The Kohler website says it has a 2-1/8" trapway, but it doesn't mention the flush valve size.
Link to Tresham toilet on Kohler website.

Edit - there's a video at that link. This toilet uses the Class Five flushing system, which claims to use a 3-1/4" flush valve. From looking at the parts diagram, I gather it's a flush-tower style design, not the traditional flapper design.

Quote:

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Originally Posted by stephenk

Even though it's a new model, this toilet is listed on the MaP website. It has a 1000g map rating.

The Kohler website says it has a 2-1/8" trapway, but it doesn't mention the flush valve size.
Link to Tresham toilet on Kohler website.

Edit - there's a video at that link. This toilet uses the Class Five flushing system, which claims to use a 3-1/4" flush valve. From looking at the parts diagram, I gather it's a flush-tower style design, not the traditional flapper design.

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A 3 1/4" flush valve with 2" opening as shown above??

Quote:

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Originally Posted by wptski

A 3 1/4" flush valve with 2" opening as shown above??

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Yes, it appears that way. Just because the flush valve is a certain diameter that doesn't mean the opening on the bottom of the tank has to be the same diameter.

Kohler appears to use a design on some of their toilets where the opening of the flush valve is larger than the opening on the bottom of the tank. I think the theory may be that it helps increase the water velocity.

Anyway, here's a video of a different Kohler flushing system. The class 5 videos I found don't talk about the flush valve.
https://www.youtube.com/watch?v=7vPU9k0OOhM

Here are a couple images from the video.

When Jamie and I had lunch with David Kohler and their head engineer, several years ago, the original Class Five was coming out, with a 3-1/4" flapper. I mentioned to them that it may be better to have a less then 3" flush valve. That even though it had been 2" for 100 years, and we were now seeing 3" valves from TOTO, that it may be time to play around with the concept and dial it in somewhere between the two sizes. At that luncheon meeting, he wasn't thinking about downsizing, but about his new marketing campaign about having the "biggest".
We disagreed on that. I'm all about what works long term. I told him if it was only about having the biggest, that someone could always bring out a "bigger" one, not necessarily a better one. It wasn't long before American Standard came out with the Champion "4". Which when you measure the outlet of that one, it's 3".

The original 3-1/4" flapper of the class five has now been replaced by the canister flush. I guess it was too big. But kudos to Kohler for making the change.

I put a tape on the outlet of the Tresham tank, just to show what the current sizing is. It's less then 2", more like 1-3/4"
The bowl seems to work, so installing the bowl at a friends home, which I visit sometimes, lets me get some "in home" reports on how it's working.
I will bug them to report back on it. I will say this, it's better then the toilet I pulled out.

FWIW, the media used to flush in the MAP testing is plastic wrapped paste...not exactly like the 'real' stuff. It's a lot easier to make more flush and not get caught up in the internals of a toilet than the irregular, not smooth surfaced real stuff. Manufacturers have figured out how to make their toilet look good on those tests...that doesn't mean it will really work great in the real world. Anything 500 or above is more than adequate for 99% of the people out there. Totos work well with the 'real' stuff.

Hey, Jim, you're the engineer in the bunch.

It's my impression that the "funnel" of the Champion and of this thing doesn't do anything to increase the water pressure at the bowl when flushed, that the weight of the water would produce essentially-similar effects whether there was an opening at the bottom of the tank with or without a funnel. (Indeed, I can see how the funnel would eliminate pressure from the side.) However, I never took a fluid dynamics class, and I know that the engineering wrt fluids is complex and sometimes counterintuitive, so...

what do you think about funnels immersed in a tank?

(PS I recognize that there may be a Venturi effect, something I learned about when wondering why the wind velocity was so much higher in the park between my old apartment towers in Chicago as compared to the wind velocity on the street. However, it seems to me that the velocity increase has no relevance to the flush in the bowl below, particularly because IIRC there's some kind of conservation at work (i.e. pressure drops and velocity increases), and I think it would probably exist regardless of the funnel at the opening. But again, I know when I don't know about stuff.)

A venturi only speeds things up for a short distance...may be enough, in this instance, but it's hard to say.

I didn't mean to distract with the Venturi thing...I thought it was just an element of useless knowledge that I could use to show how little I actually know.

I'm wondering more whether the funnel does anything meaningful other than provide a marketing gimmick: "We have a 4" valve!!!"

Hey Terry
Brian and I wanted to thank you again for the wonderful new toilet!!! We really do love it! Not only does it look fantastic in our home, but we are marveling at how little water it uses – and that really speaks to Brian’s desire to be efficient in all that we do here at the house.
C