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by thunderbong·5y ago·view on hn ↗
I couldn't understand why one type of cistern would waste more water than another.

This point from the article which comes further down in the page explains -

>> The majority of them use the drop valve system, which sits at the bottom of the cistern and opens to allow the water to flow out when the flush is pressed. Debris and other issues can cause the mechanism to fail to close, meaning water continually flows from the cistern and into the bowl.

>> Older cisterns tend to use a siphon system, which works by pushing water upwards until it reaches a point at which it can flow into the bowl. Because that point is above the waterline when the toilet is not being flushed, the system is less likely to develop the same sort of leak.

4 comments
Every single toilet I've seen in the US over the past several decades, single or dual flush, has used the more leak-prone drop valve system anyway. So here in the US at least it doesn't sound like dual flush will be contributing to more leakage.

There is a bigger problem here though, which is that manufacturers seem to have no incentive to develop leakproof designs since they aren't paying for failures, and there isn't strict enough regulation on these products.

The reason for that problem is that no one really cares and it isn't as big of an issue as it seems. Toilet is running? Jiggling the handle is likely to free up the debris that is blocking the valve, since the debris obstructing the valve is the chain itself that controls the valve flap. Once in a blue moon the chain may slip off the handle, but that only requires fishing your hand in and reattaching the chain. No one is going to bother reinventing the wheel and finding 100 more problems in the process in order to fix what is probably 5 seconds of effort a few times a year.
yes, but US toilets are disgustingly wet.
I'd like to point out the California approved portable gas cans. They were intended to prevent spills, but they suck so bad, that spilling is more likely than ever before.
I hate those, I spill gas everywhere when trying use them. I have seen Youtubers, etc. showing DIY mods to disable the spill spouts.
5 minutes with a utility knife dramatically improves them.
There's too many parts trying to do too much. The seals leak, the sliders bind, the whole thing is large and difficult to maneuver. It's better to remove the filler assembly and just pour out, maybe using a funnel if the target is small. Roads and good intentions I guess.
I have 5-gallon cans, holding them high enough to use a funnel with a car would be very difficult or hard to control.

I am about to try siphoning.

The VP Racing gas cans are great.

https://www.amazon.com/VP-Racing-Fuels-3512-Motorsport/dp/B0...

Sounds like to problem the British had in ww2 until they copied the German "Jerry" can - The original UK ones where called flimsies.

The US sensibly learning from the UK just produced an improved version.

This is a personal rant, but here it goes. Living in a country with very hard water and after changing the plunger it takes a few months but inevitably it starts to leak. Doesn't matter whether it's single or dual flush. It's like the germans make these to leak so you have to replace the tank valve every so often. Of course, you have to buy one specific to your model and of course you can't just buy the small sealing gasket because that would actually save the environment. Sometimes cleaning the damn thing to remove dirt and limescale or rotating the gasket helps.
I'm surprised these aren't standard. Most American gravity-tank-flush toilets use the same flush valve, and most of the remainder are the tray-tip kind that doesn't really have a flush valve in the traditional sense. There are exceptions and oddities, but it's really nice having singles. Also does mean you can buy just the single part you need. I have no idea how we of all places managed to get this right.

Also I do wonder if a scale preventer injector (they go online like a water filter) would be more or less expensive than the toilet parts?

Siphon cisterns don't have this problem, because there's no valve - or rather, there is a valve in the form of a flap of plastic, but it's to lift the initial bit of water over the siphon and not block the rest when it follows.
Why you can't design a dual siphon model is a bit beyond me.
I mean, you could, but it would probably end up being so complicated that it introduces failure points elsewhere.
I lived in one of the hardest water areas in Britain for a long while. Standard syphon flush mechanism was never a problem. May be worth a try. The newer replacements are vastly less durable.
What about siphon system? Is it also afffcted by hard water?
It's not just the valve getting clogged. The design on all horizontal models of these that I've seen have very flimsy plastic rods connecting the buttons to the valve mechanism. When the rods inevitably break, the valve somehow fails open.