Grossly Insufficient Water Supply To Toilet Wasting Water? - Plumbing - DIY Home Improvement | DIYChatroom

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Old 01-12-2011, 07:42 AM   #1
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Grossly insufficient water supply to toilet wasting water?

I have to admit that for all my supposed genius, I don't understand exactly how the toilet works. Sure I understand the basics about the float valve and the flapper, and see how the overflow tube is arranged to allow water to flow into the bowl if the float vale should fail. I know the toilet is fairly unique in that is has a trap designed into it, as opposed to the traps associated with sinks. I know all about the importance of proper venting and how to diagnose a poorly or improperly vented toilet.

But I'm a but I'm challenged to explain why some water is intentionally diverted into the overflow tube while the tanks refills. Originally I thought it was to help rinse the bowl of solids, now I'm thinking it's designed to ensure the trap in the toilet is refilled in case it is siphoned dry during a funky flush.

At first I thought the toilet at issue was a classic case of "running on". I eliminated the flapper valve as a cause and tried adjusting the float: eventually, all the way down. This seemed to solve the problem temporarily, but the problem came right back. At first I was convinced the valve was defective, but by raising the float manually, the valve closed as it should. At this point I had two working theories: that the acme-threaded rod that connected the float to the valve was stripped, or turning of its own accord due to vibration. My other theory was that the float was somehow damaged or waterlogged. At any rate I decided it was time to punt the problem into the landlords lap and forget about it. The renter procrastinated, she had much bigger fish to fry than worrying about the toilet.

But a few nights ago I got frustrated with the situation again and decided to remove the cover from the tank for a few days, and observe more carefully. I noticed that during the times when the toilet was quiet, the water line in the tank was far below normal, as one would expect if the float were turned down. As I screwed it back up, I could get the tank to fill to the "fill" line. But it took an extraordinary amount of time. During this time, water constantly flowed out of the flexible tube that went from the valve to the overflow tube. So much water, in fact, it competed effectively with the amount of water flowing through the float valve and into the tank. The float valve had a very slight advantage, so after about 30-60 minutes (!) there was enough water in the tank to close the float valve. The noise I was hearing was not coming from the bowl or even the float valve, but from somewhere deep inside the supply piping. Obviously I thought at first the service valve was nearly closed, but discovered it was wide open. It worked as it should, stopping the flow when turned down. But after the first turn off it's seat, it was obvious the service valve was not the limiting factor in the flow of water.

I removed the flexible tube from the overflow tube and observed it flowing at an approximate rate of .25 gallons per minute. I observed that the water in the bowl became still soon after diverting the flexible tube into the tank, and resumed some time after the flexible tube was re-inserted into the overflow tube. With the flexible tube diverted to the tank, the tank filled in about five minutes.

At that point (tonight) I became convinced that insufficient water supply was the root cause of all the mysterious behavior and was wasting huge amounts of water. For each flush, I estimate that at least 5 times as much water is being wasted down the overflow tube as is used to refill the tank. I expect that normally, the reverse is true: only about 20% of the water passing the float valve makes it down the overflow tube, if that. "Negligable".

Do you think my diagnosis is correct? Have you seen this before, and is it common? I've successfully fixed more than a dozen toilets for friends and family and around my own home. I've seen some pretty wild things including a steel chain galvanicly eat its way through an aluminum, uh, flush handle extension rod (I used a nylon tie to isolate the dissimilar metals and the repair is still going strong 5 years later). But I'd never seen this before or considered what might happen to a toilet if the water supply was severely restricted. I've never seen it mentioned as a possible cause for trouble in any DIY guide: least not so far as I can recall.

Oddly enough, I would often advise friends to choke off the water supply of suspect toilets. That way, if it did misbehave, at least the loss of water would not be catastrophic. As I let the water flow at about .5 GPM in those other cases, refill (although heavily impacted) was still reasonable: 2 -5 minutes versus about 15-30 seconds wide open. At the time this was seen (again in a commercial/office shared toilet situation) as a considerable inconvenience, but the only tradeoff. By choking down first all of the toilets and then re-opening the valves one at a time, over the course of some weeks we (myself and the landlord, who turned to me in desperation) narrowed it down to a single person who probably never noticed the toilet was running on. During the day the other office workers all knew you had to jiggle the toilet handle to prevent it from running on, and consciously or unconciously "enabled" this persons behavior by jiggling the handle, perhaps even stepping in explicitly from time to time to jiggle the handle when the toilet was heard to be running on. But if and when this person was the last to leave the building, ie the last to use the toilet, it would run on all night: and one or two nights each month was enough to severely upset the water bill. Ultimately the problem was a flapper valve that would only misbehave when we weren't staring right at it. I either replaced it or twisted it slightly so it would seat properly. That was the end of the mysterious high water bills.

My friend (with the toilet currently at issue) had complained about the toilet to the landlord a couple years ago. I don't remember what the original complaint was, but in response she ended up with a "newfangled" float assembly. I was very suspicious of the all-plastic thing and was convinced for a long time it was at the heart of the problem, and she just needed a good ole' fashioned metal ball float. In retrospect I wonder if the landlord choked down her supply water on purpose at the time the float valve assembly was replaced. It's equally likely that the low supply water was the cause of the original complaint, and the "plumber" who replaced the float missed the diagnosis. I use plumber in quotes because the chances are even the landlord didn't hire a licensed plumber to do the repairs, instead relying on a "handyman". Much better than even, I'd say.

It's late, I'm done. Thank you in advance for any considered opinion on the matter. At this point i consider it an emergency that the landlord must be told about. Below the residence is a deli, and the high water bills are probably being written off (literally and figuratively) as due to the commercial operation. Whether it means opening a valve over which only the landlord has control, or replacing a piece of 100 year old galvanized pipe, I think the project would pay for itself within a few months at this rate and the resident is not doing the landlord any favors by "not complaining" about it.



Last edited by mysterylectric; 01-12-2011 at 07:52 AM. Reason: clarity
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Old 01-12-2011, 08:07 AM   #2
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Thanks for making your lengthy diagnosis somewhat entertaining.
The purpose of the tube going from the fill valve into the overflow is to keep the water level in the bowl to a proper flushing level. If one were to remove that supply of water from the overflow, you'd have a weak flush about every other time or so as the flush would have to fill the bowl up and above normal level before it flushed. Sometimes there isn't enough water in the bowl to do all of that before the flapper closes. All toilets are designed differently. You have diagnosed the need to replace the fill valve. The choice is yours whether or not you want to replace it with the traditional "ballcock" or if you want to use a more easily installed and adjusted fill valve such as a Fluidmaster. I used to swear by the "ballcock" but the newer toilets often don't have enough room in them to use all of the extra material. The Fluidmaster fill valve will fit virtually any toilet. Have had very little issues doing so.


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Old 01-12-2011, 09:52 AM   #3
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Ah, so what I'm calling a float valve is normally referred to as a fill valve. I'm still convinced the fill valve is fine, and that low water supply is the real issue. I'm going to test my theory by choking the water down further. I bet it won't take much throttling before I can ensure the tank never fills, and spills water down the overflow indefinitely. On the other hand, I'm fairly certain I can "trick" the system as it now stands into performing correctly by dumping an extra gallon or two of water into the tank soon after flushing.

In fact that won't prove the fill valve is good, as I don't have any more than a rudimentary understanding of how it is built to behave. I'm assuming it's simple: all water goes first through the fill valve, then a portion is diverted into the overflow as long as the fill valve is open.

Seeing as one of my hats is as a process engineer and I know how a few inches of watercolumn pressure can make a lot of difference, it does beg the question in my scenario: why does the water seem to prefer defying gravity and go "high" through the flexible tube, even when the end of the tube is held a few inches above the overflow tube, and the tank is only a few inches full?

Hmm, I gotta run back to my friends house and look into things yet more deeply.

I'll be back soon

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Old 07-27-2011, 08:29 PM   #4
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As a followup here, once I had the toilet supplied properly I was horrified to realize that wasting at least 15 gallons per flush was completely normal for this 50+ year old toilet. I was simply witnessing it in slow motion.
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Old 07-27-2011, 09:14 PM   #5
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15 gallons per flush seems a little extreme to me.

No offense intended, but i'd have to see some real in depth video documentation to believe that it is actually that high.
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Old 08-02-2011, 06:17 PM   #6
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Maybe I can time the discharge from the (diverter?) tube into a container, time the fill period, and come up with a better estimate.

I'm sure clamping the tube would help a lot, I think a 5 cent hose clamp is bundled with the "water saving" versions of this float/valve kit...

A brick in the tank wouldn't hurt either.

Hmm, maybe I should consider that what ties the before and after behavior of the toilet was in fact Fluidmasters. I didn't mention that the toilet had a Fluidmaster when I started looking into it, and that I replaced it with one before concluding the problem was in the toilet design.

Hmmm... guess that $4 clamp is pretty much mandatory in The City. Where water costs are %80-90 lower, no big deal.
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Old 08-02-2011, 06:30 PM   #7
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I own/operate a "HandyMan" type business to I do see toilet problems quite often. One thing I have found out about the "Fluidmaster" type units is that even a very tiny bit of debris under the diaphragm in these unit will make them act erratically. Shut off the water supply to the toilet, remove the cap on top of the Fluidmaster type unit, carefully remove the rubber diaphragm, turn the water back on just enough to get water to flow but not spray all over. Take the diaphragm to a sink and wash it thoroughly to remove any debris, I like to use an old toothbrush to make sure it is clean. Replace the diaphragm making sure to align the little needle valve with the hole in the diaphragm, replace the cap on top, and turn the water back on slowly. Hopefully this will allow the water to flow into the unit properly and you can now reset the float for the water level.
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Old 08-02-2011, 06:40 PM   #8
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15 gallons seem high to me and I am the owner of four 'high volume' toilets (6-7 gallons/flush) circa 1940 (when our 200 year old house was "completely modernized with indoor plumbing ).

After lots of reading here are my thoughts:

- don't do a brick - if you must reduce the internal volume of your tank; fill a clean 1/2 gallon milk jug with water and sink it. Many bricks may survive in your tank, but some will break down and cause problems. I bet you have some left over plastic bottles in your house......

- 'Choking off' the supply just makes it fill slowly. This may be helping your fill valve if it is no longer working to spec.

- Fill valves are CHEAP and EZ to replace. Replace yours. I've got both Fluidmasters in my American Standards and a hand-re-built fill valve in my two piece (odd-ball) Case. I have had Fluidmasters go bad.

- Generally, plumbing valves should be 'all the way open' or 'all the way closed'. Most aren't really made for volume/pressure regulation - being constantly in a partially open position may damage the internals of the valve and make it so you can't close the valve in case of emergency.

- Most of the time old toilets means larger diameter waste pipes. Lowering your flush volume (by brick/lowering your float/replacing with low flow/ etc) can result in more clogging in your waste pipes.

- My experience with family and friend who have low flows is that they require more flushes to eliminate waste and clog more frequently. The exception being brand new construction designed for low flow toilets paired with high quality low flow toilets.
If I could only remember to THINK about what I was doing before I did it.
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Old 01-17-2012, 11:19 AM   #9
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Also, think about the low flow rates already inherent in braided stainless steel supply lines. The inner diameter is MUCH smaller than they would have you think because there is a pretty thick rubber hose on the inside of that stainless steel braid. If you want higher flow for faster tank fill, the only company I've found with a solution to this is Falcon Stainless. They make a 1/2" toilet connector with literally a .465" inner diameter. You can't even touch that with braid. There will be significantly higher flow and less wasted water going to the overflow tube in the process.


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