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Boston Standard Plumbing & Heating: Toilet Flush Technologies, Part 1

Power outages remind us of how difficult life can be without modern conveniences, but going without one relatively recent addition to modern households can be downright torture! I’m talking about the modern flush toilet. In Boston, there are a variety of toilet technologies in use, from the very old to the most modern. As Boston plumbers, we see it all.

Toilets have been around for a long time. Archaeological evidence from Britain as far back as the 31st century BC shows us that some households at that time had hydraulic toilets. Virtually all homes in the Indus Valley had flush toilets connected to underground sewer systems in the 26th century BC. Flush toilets were also used throughout the Roman Empire until the 5th century AD, when the Roman Empire fell, and flush toilet technology was for the most part, lost in the Western Hemisphere.

In about 1200, an Arabic inventor developed a combined sink basin and flush toilet. The user would use the toilet, wash his hands and then drain the waste water to flush the toilet. (These water-saving toilets are making a comeback in Asia and Europe today.)

But where did the modern toilet come from and how exactly does it work? Today’s toilet is the product of a lot of small innovations on the user’s end, and the creation of modern sewer (or septic) systems. Most of the important inventions involved valves that started and stopped the flow of water; waste containment systems or sewers; and traps that both hold the water in the bowl and prevent noxious sewer gases from escaping into the living space.

In the 1880’s in Britain, Albert Giblin and Thomas Twyford designed different toilet systems, which Thomas Crapper built. Unbelievably, there is no relationship between Thomas Crapper’s name and the word “crap.” “Crap” (whose meaning hasn’t changed a bit) entered the English language long before Thomas Crapper entered the world!

Crapper popularized (but did not invent) the siphon flush system, which we still use heavily today. Additional innovations have allowed the use of pressurized water to empty the bowl more reliably, provide shorter recharge times between flushes and supply a self-cleaning mechanism to keep the bowl in good shape. These pressurized systems are most often used in commercial appliations.

Most residential toilets are of the gravity-fed variety. Basically, these toilets have a tank of water suspended above the bowl. The amount of water in the tank varies, based on the age of the toilet. The newest toilets use anywhere between 1.28 and 1.6 gallons of water per flush. Older toilets may use more than 5 gallons per flush.

Each gallon of water weighs 8 pounds. The toilet tank has a strong flapper valve at the bottom, which prevents water from leaking into the bowl. When the flush handle is depressed, the wide flapper valve at the bottom of the tank opens and the tank water rushes like mad down into the bowl. With older toilets, the more water you have in the tank, the more sustained pressure you can create in the bowl. The newer toilets operate differently, and as you’ll see in my next post, they’re just as effective at clearing the bowl as the older water-hogs are.

A trapway, which is built into the porcelain of the pedestal, is set at a very sharp angle and makes an upside-down U-shaped bend. You can see the trapway built right into the porcelain if you look near the base of the toilet almost directly under the tank. When the water in the bowl reaches the height of the inside curve of the U bend, a siphon is created and the wastewater is sucked out of the toilet and down the soil pipe.

On the topside of the toilet, the water rushes out of the tank and lowers a float valve. When the float valve reaches a certain angle, it opens a fresh water valve to refill the tank with clean water. Meanwhile, the flapper valve at the bottom of the tank closes to hold the fresh water in. As the water level in the tank rises, the float valve rises, too. When the float valve reaches a certain, pre-set level, the fresh water valve closes and the toilet is ready for the next flush.

If the float valve is not adjusted properly, some fresh water may leak into the tank. To prevent overfilling, there’s a relief tube that has a separate drain path around the flapper valve and into the bowl. If your float valve isn’t working properly, you’ll hear regular drainage into the bowl and the water level will rise. Once it fills the trapway, the water will drain out of the bowl.

On the other hand, if your flapper valve is leaking, you’ll still hear draining water, but periodically, your tank will fill for a short period, then shut off. The excess water will also fill the bowl. When it fills the trapway, the bowl will drain.

If you’re having trouble with a leaking toilet, and you don’t have the tools or the time to make a repair, contact the professionals at Boston Standard Plumbing & Heating. We’ll be happy to fix your leak. We can even recommend water-saving toilets that we know you’ll be pleased with. Contact us at (617) – 288-2911 anytime!

In my next post, I’ll talk about new flush technologies and how they can save water without sacrificing performance.

Running Toilet? Fix it!

One of the most common plumbing problems in Boston homes is a running toilet. Running toilets are not hard to fix, but may require a trip to the local home improvement or hardware store. Evidence suggests that flush toilets have been around since about the 26th century BC, but they didn’t much resemble the modern toilet. Strong evidence suggests that flush toilets were used in homes during the Roman Empire but were lost when the empire collapsed.

Flush toilets of one kind or another were also found in a few Colonial homes, but the modern toilet we recognize today came into vogue around the time of the Civil War and the first china toilet was made in 1885. Since that time, homeowners have had to deal with the aggravation of a running toilet!

If you’ve never watched a toilet in action, remove the top of the toilet tank and flush a few times. Chances are good that you’ll see a full or nearly full tank of water before the flush, and a “flapper” valve that opens when you depress the flush handle. The flapper valve is attached to the flush handle by way of a chain, cord or similar connector. The open flapper valve allows clean water from the tank to fill the bowl and drain the bowl’s contents into the waste pipes below the toilet. For the most part, it’s a gravity-based system.

When the water level in the tank drops below a certain level, an inlet valve is triggered and the tank begins to fill again. The weight of the accumulating fresh water is supposed to close the flapper valve at the bottom of the tank. The float – a large balloon-shaped device attached to a lever, rises with the water level in the tank. The water lifts the float lever to a certain point and shuts off the flow of water from the inlet valve when the level has reached a certain point.

So.. naturally there are a few things that can go wrong. The chain that attaches the flush handle to the flapper valve can become disconnected. If this happens, the toilet won’t flush at all and the flush handle will remain in the down position all the time. Simply reconnect the chain to the flush handle or the flapper valve and you’re good to go. If the ring that holds the chain on either end has broken, you’ll need to replace the broken piece with a new one. Easy peasy.

The float could be adjusted too high, meaning that the tank fills with more water than necessary. The extra water is shunted off through an overflow valve right into the drain and produces a running water sound. To repair this, adjust the float lever so that it shuts off the inlet valve sooner. The new fresh water level in the tank should fall below the top of the overflow valve.
The flapper valve at the base of the tank can also leak, allowing the water level in the tank to drop, which will eventually trigger the inlet valve and producing the “classic” running toilet. The flapper valve can have any number of designs (or design flaws) that can cause the valve to stick or misalign with the tank opening. Likewise, the flapper valve itself can deteriorate over time and become unable to form a good strong seal. If you can’t tell why the flapper valve isn’t closing properly after watching it in action a few times, the easiest repair is to replace the valve. Home improvement and hardware stores sell a toilet tank replacement kit. The kit parts are designed to replace the entire mechanical structure of your toilet tank and should repair all water flow issues associated with the operation of your toilet.

If you haven’t ever worked on a toilet, or would like expert assistance with repairing a running or leaking toilet, contact Boston Standard Plumbing at (617) 288-2911.