Kohler canister flush valve question

I was at Home Depot yesterday and there was a Kohler toilet tank sitting out on a shelf (someone must have taken it out of the box or something). It had a canister flush valve that looked to be the same diameter as a standard flapper flush valve. They called it their "aqua piston" something.

Would it be possible if someone were to buy a new Kohler Wellworth toilet, remove the canister flush valve, and put in a regular flush valve with a flapper? Would the toilet work fine? I can just see the canister failing if someone had very hard water.

Peterson said:

I was at Home Depot yesterday and there was a Kohler toilet tank sitting out on a shelf (someone must have taken it out of the box or something). It had a canister flush valve that looked to be the same diameter as a standard flapper flush valve. They called it their "aqua piston" something.

Would it be possible if someone were to buy a new Kohler Wellworth toilet, remove the canister flush valve, and put in a regular flush valve with a flapper? Would the toilet work fine? I can just see the canister failing if someone had very hard water.

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The flapper would fail way before the canister would. The canister is made of plastic, while the flapper is made of rubber. I would recommend that you keep the canister in the tank. It gives more flush power. But if you really want to, you can replace it by turning the water supply off, flipping the tank over, and with tongue and groove pliers, put them on the white nut, and turn it counter-clockwise until the canister gets loose and can come out. To install the new flapper, put the new flapper in the hole at the bottom of the tank, put the new nut on it, and turn it clockwise until it is snug. Then, just put the tank back on, re-connect the water supply, and you'll be good! Hope I helped!

It's pretty easy to change the seal on the Piston. Unthread the keeper on top and lift out the cannister.






I don't think there is a need for conversion. I would use it "as is" out of the box.
With hard water, you will have maintenance no matter what you install.

Can't think of a reason why it would work better, but it is different, keeping in the tradition of NIH that infects Kohler.

Thanks guys! I'm not in the market for a new toilet, but I liked the looks of the Kohler if I was.

I was just curious about changing out the canister if I should happen to buy a Kohler. I wouldn't want to buy something and then run into the problem of not being able to get parts, etc. where I could always buy flapper anywhere if needed. I also read on this forum about the canister getting stuck, or falling too quickly, etc.

I have an older Mansfield in my house and years ago I removed the flush tower and installed a flapper valve in the tank and it works great, if not better. I was wondering if the same would apply to the Kohler.

I have an older Mansfield in my house and years ago I removed the flush tower and installed a flapper valve in the tank and it works great, if not better. I was wondering if the same would apply to the Kohler.

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I'm tracking a few with the cannister valve and they seem to be working.
These are Kohler products I've installed in the last year.
The wholesale outlets I buy from have the parts. I have not paid much attention to the home centers. I'm not in those places much.

We have also done the seal repair on the new flush valve, so it's all doable by a DIY.

We have recently got a new Kohler Cimarron Class 5 with an Aquapiston Canister, the toilet is really great, I recommend to keep the aquapiston, much more reliability and sealing on the Aquapiston.

Per Kohler's spec sheets, the Cimarron has "AquaPiston" and others (e.g., Welworth) have a "Class 5" flushing system.
Are these two different ways of marketing the same thing?
Ed

This is true, The Aquapiston is class 5 as well. The wellworth and other class 5 toilets come standard with an aquapiston.

As I've said before, 'Class x' is a totally Kohler marketing thing and has no general industry standard. Each time they try to make it more efficient (either in cost or performance), it 'obviously' must be better, and they bump the class designation up - the implication is that if the class is higher, it must be better. So, only practical experience will show (eventually) whether there is actually any improvement, and in the meantime, the parts catalog keeps getting bigger making it harder for anyone to find the right part for their now orphaned design. 98% of the rest of the industry keeps the mechanical parts the same and refines the guts in the porcelain. After all, how many times do you need to redesign the fill valve, and flapper valves have been around for probably close to 100-years or more. But, Kohler likes the fact they designed it (aka, NIH, not invented here syndrome) even if the part ends up costing 3x as much and parts aren't reasonably available and it doesn't necessarily work better (just different!).

Contrast this to Toto, who obviously does change things, but has one fill valve that can replace nearly all of the toilets sold over the last few decades. It has a little dial, and depending on the model you have, you look at the chart and set it there, and the bowl/tank ratio of fill is proper and it plain works.
They do make some nice stuff, but personally, I think there are often some better alternatives.

Actually, I was able to communicate with someone from Kohler, and the AquaPiston is NOT the same as the Class 5 system. I believe it has a slightly larger diameter to the cylinder, and it recently started shipping with a silicone seal.
I do not know if the two are interchangeable, but I would guess not.
Ed

Kohler sucks, it just dont flush....the canister type flush valve (aquapiston) is a nuisance, have to hold the handle down to flush solids. Being practical, some water saving devices just waste time, and really dont save much water at all...either flush once or 3 times...geez.

tnman said:

Kohler sucks, it just dont flush....the canister type flush valve (aquapiston) is a nuisance, have to hold the handle down to flush solids. Being practical, some water saving devices just waste time, and really dont save much water at all...either flush once or 3 times...geez.

Click to expand...

There must be something else wrong with yours. I have installed Kohler with the Aqua Piston and have had no problems.
They work well with the 1.28 gallon flush for solids.

I see that many of you out there have had this problem, but having encountered this before, I'm going to share a 100% fix for your Kohler toilets with those sucky canister valves...... You only need replace the canister assembly with a Keeney flush valve assembly. See link below to view models online at Home Depot, which is only one of many sources for these valves. I would recommend Keeney flush valves to fix any of your low volume flushing problems. Key is to increase water volume in the tank, and have a flapper that floats long enough to give the toilet a long drink/flush.

They come in many sizes. Currently I am replacing one of those big 3" canister valves with a 3" Keeney for my Kohler Cimmaron 1.6gpf model. You can get them online, or from Home Depot. It is an oversize flapper with solid gasket design and adjustable..
The overflow neck is adjustable, and ratchets up to give you more water to flush with. This REALLY works for those of you who like Kohler design toilets, but simply hate their stupid ecofriendly flush valves that don't work. Regards, Doc
https://www.homedepot.com/s/keeney%20flush%20valve?NCNI-5