Faucet Basics: Part 2
Faucet Valves & Cartridges
From the point of view of the mechanics involved, a faucet is nothing more than a valve that controls and directs the flow of water through a tube. The main components are the valve itself, a body to contain the valve, a handle to turn the valve and a spout through which the water flows.
The valve is the most critical part of the faucet. If the finish flakes or peels, your faucet may no longer be pretty, but it's still a faucet. But, if the valve fails, the faucet stops being a faucet. It cannot perform its essential function: delivering measured amounts of water. The faucet valve, therefore, should always be the best valve you can afford, and valve reliability should be the most important consideration when buying a faucet.
Any valve consists of two parts. The moving part, attached to a handle or "stem", and the fixed part. To shut off water flow, the moving part is pressed against the fixed part until the water stops. The fixed part is usually called the "seat".
Before the replaceable valve cartridge was invented by Al Moen in the 1930s, the valve stem moved up and down inside the body of the faucet itself. Today the valve is usually built into a removable carrier called a cartridge. The cartridge inserts into the body of the faucet. Any wear on the valve takes place inside the cartridge, not inside the body of the faucet. If the valve fails, the cartridge can easily be replaced, restoring function to the faucet. Before removable cartridges, the faucet body would have needed to be re-machined or replaced.
The removable cartridge can make upgrading painless. For example, the company typically sells its faucets equipped with the company's venerable Quaturn® compression valve. But, if you want a ceramic valve instead, it slips right into the same socket. The faucet does not need to be modified to accept the newer valve technology. Many faucets are built the same way: they will accept different types of cartridge.
Mixing faucets, especially single handle mixing faucets, require a more sophisticated valve with more parts, and therefore, more things to go wrong. Yet, valves are more reliable today than they ever have been — a testament to the great strides that have been made in materials, engineering, and manufacturing.
The modern ceramic cartridge valve should last a minimum of five years before it needs to be replaced, and some better valves never need replacing. They will outlast you, and probably your house.
"Washerless" valves from were a giant step forward in the 1960s. These valves still needed to compress rubber seals to shut off the water, but the new design eliminated the twisting motion that wore out rubber seat washers so quickly. The rubber or silicon seals in washerless valves could last five years or even longer as the technology improved.
The newest technology, ceramic disc valves take this a step further by eliminating all friction on the rubber or silicon seals that causes the seals to wear out over time. Water flow is controlled by nearly indestructible ceramic discs, not silicon or rubber seals.
Compression and Fuller Valves
The earliest type of valve was a device that pressed a plug into a seat to stop water from flowing and retracted the plug to allow it to flow again. For much of the first 70 years of faucet development, there were two competing technologies: the compression valve that used a screw mechanism to control the plug, and the Fuller valve that controlled the plug with a lever and cam.
The first practical compression valve was patented in 1845 by Guest and Chrimes, a brass foundry in Rotherham, England.
The device used a stack of leather washers as a plug. Turning the handle of the faucet raised and lowered a stem. The plug, at the base of the stem, was pressed into a metal (usually brass) seat until water flow stopped. To start water flowing again, the plug was retracted by turning the screw the other way.
It was a great improvement over earlier water control technology that consisted of some version of driving a plug into the end of a pipe to stop the flow of water, often with a mallet, and removing it to start water flowing again. It made bringing water into the house practical because it could be precisely and reliably controlled.
The screw action that opened and closed the valve worked well but also wore out the leather washers fairly quickly by repeatedly grinding them into the seat. Even after the switch from leather to rubber washers, the problem of rapid washer deterioration continued, abated only somewhat by improvements in washer technology.
The Fuller Valve
What was needed with a technology that pressed but did not twist the plug into place so it would last longer, and of Brooklyn thought he had the answer. His invention, patented in 1879, used an eccentric cam attached to the handle to press a grape-sized rubber ball 1 into the seat. The cam took advantage of mechanical leverage to push the ball into place, shutting off the water.
Unlike the compression faucet that operated against the stream of water, the Fuller valve worked with water pressure to improve the seal. Since the cam mechanism did not grind the rubber ball to stop water flow, the mechanism lasted much longer between repairs.
The cam required only about a half turn to bring the flow of water from off to full on, but precise control of flow volume was tricky and required a deft touch. Moreover, according to generally accepted plumbing lore, it could take a lot of force to squeeze the ball into its seat hard enough to stop water flow, especially as the ball wore down, so large lever handles were common to provide the needed leverage.
The Repair of Leaking Faucets
"The Shipshape Home"
-o- January 1925 -o-
Washers for both types of faucets usually are available at a 10-cent store and always at a hardware shop. The expense is so small that one can well afford to keep one or two washers in store for each kind of faucet, just as extra fuses are provided for the fuse box.
Click to Enlarge Image
To repair a compression faucet:
- Shut off the water at the valve on the main line leading into the house. This will usually be located near the water meter. Every housekeeper should know where it is and how to operate it in case of serious faucet trouble or broken or frozen pipes.
- Open the faucet and let the water drain out.
- Loosen the cap (packing nut) with a monkey wrench or large automobile wrench. To prevent scarring the finish, put a rag around the nut before applying the wrench.
- Unscrew the valve stem by turning the handle to the left until it is removed entirely. This is all the disassembling necessary. Now loosen the screw holding the disk washer.
If the head of the screw has corroded to such an extent that it breaks, cut out the washer first and turn the screw with a pair of pliers. Fasten the new washer in the recess from which the old has been removed, trimming it to fit if necessary. A rubber, fiber, or leather washer may be used. A hard washer is preferred for hot water and a soft one for cold. Examine the seat for the washer and make sure that it has not become rough where the washer was worn away. If it has, it should be smoothed. This can often be done with a screwdriver or the square end of a narrow flat file. Some faucets have seats that can be replaced with new ones.
Put the valve back in place and tighten the packing nit. If the faucet turns too hard, the packing nut has been made too tight.
- Shut off the water at the main valve and drain the faucet.
- Disconnect the faucet at the middle joint. This is necessary because the washer is not located on the valve stem and is not accessible from the top of the faucet. If there is no middle joint, the faucet is of the compression type; this is the most obvious distinction between the two kinds.
- Replace the rubber ball or washer by removing the small nut. Put in the new robber and replace the nut. Reassemble the faucet after having examined for other possible troubles.
Brian Marrone, whose company, Brians Plumbing Works in Gladstone, Oregon, repairs and restores original fuller faucets, disagrees with this traditional view.
The large handles, he says, were ornamental — a Victorian style preference — not functional. As the Victorian era gave way to the Arts & Crafts movement in interior decoration, large levers disappeared. The lever handles on Fuller faucets were no larger from those found on compression faucets.
According to Brian, extreme force applied to the lever would deform the eccentric post at the end of the main stem, damaging the faucet. He writes:
I have worked on many Fuller valves at this point and most of them do not have terrible wear on the stems. The balls are all corrupted and the seats need to be honed but the stems are, more often than not, in fair condition. From this, I conclude that they were set up to not be forced.
Compression Valves Today
In the end, the Guest & Chrimes screw-type compression faucet won the day. Better design and improved rubber made compression faucets more reliable as time passed. By the turn of the 20th-century compression valves that required a number of turns to reach maximum water flow were being replaced by newer models that required no more than a quarter turn. This put much less twisting force on the compression washer, further reducing wear and extending the life of the washer.
Fuller ball valves, despite several improvements in the technology over the years, started to die out in the 1920s and are no longer to be found. Even replacement parts are becoming hard to find> 2 .
Compression valves are still widely used, just not in home kitchens or baths. A type of compression valve called a "Bibb" valve can be found in outside faucets (which are called "bibcocks", "spigots", "wall hydrants", "hose hydrants", "garden valves" or "hose bibbs" — depending on where you live in North America — just a little plumbing trivia, for fun).
Compression valves are also the preferred valve in restaurant and hotel kitchens where the ease of replacing the compression washer outweighs the nuisance of having to replace it more often.
An Arbys kitchen cannot shut down for a day waiting for a replacement ceramic cartridge to arrive by FedEx, it needs to be able to get a malfunctioning faucet working again right now, and replacing the compression washer — which typically takes about 10 minutes and uses parts that every plumber always has tucked in his or her toolbox — usually does the trick.
This is why the standard valve used by companies like the that specialize in heavy-duty faucets for restaurants, hotels, and medical facilities is a quarter-turn compression valve. The Chicago Quaturn® quarter-turn valve has been in continuous use for over a century and shows no sign of going away any time soon.
The Washerless Revolution
The compression valve had a long and impressive run in household faucets. It was king until the 1960s, and every homeowner learned how to replace a valve washer (see sidebar above) — a task that was required every year or more often as the valve seat wore. If you delayed in replacing the washer, the valve seat might be scratched or damaged and honing the seat back to pristine smoothness might require the services of a plumber or at very least a DIY-er with a hone and precise touch.
The washerless valve completely changed the plumbing landscape, making the single-handle mixing faucet possible. Today 40% of all faucets sold in North America are the single-handle type. Plumbing and Mechanical Magazine has spotlighted the washerless valve as one of the greatest plumbing innovations since 1900 along with the In-Sink-Erator disposer (1927), Kohler's integrated apron alcove tub — the most common tub type in use. (911), the Watts pressure relief valve that made safe water heaters possible (1930), and Eljer's sanitary vitreous china toilet tank that replaced the tin-lined wood tanks then in use. (1903)
The Moen Sleeve Cartridge
Al Moen's washerless valve, invented in 1937, eliminated the rubber compression washer entirely and ushered in the era of single handle "mixing" faucets. Although it still used rubber (and later, silicon) seals and O-rings, the seals are not twisted and ground down by the operation of the faucet, which made them last much longer.
Identifying Your Moen Cartridge
The Moen valve is a cylinder inside a sleeve. The faucet handle moves the cylinder up and down in a sleeve to control the volume of water and rotates it from side to side to control the water temperature. This is done by aligning strategically placed holes in the cylinder with matching holes in the sleeve. When the holes are aligned, water can flow, when not aligned, water stops flowing.
When the handle is rotated left, the hot water inlet is aligned so hot water flows, when rotated right, the cold water inlet is aligned and cold water flows. In any position other than far left or right, the hot and cold water is mixed to varying degrees of warm water.
"Moen motion" has become the standard for all single-handle faucets made since. No matter the style, source, brand or manufacturer of a single-handle faucet, moving the handle up or back turns the water on — the further up or back the handle, the more water you get. Down or forward turns it off. Right delivers cold water and left supplies hot water. As a consequence no one has to relearn how to operate his or her faucet every time he or she buys a new one — they all operate the exact same, Moen, way.
Al Moen patented the new valve in 1942 but had to wait five years manufacture it. During the World War that ended in 1945, brass needed to make faucets was strictly earmarked for munitions and other military use.
Moen faucets were the "modern" feature of many of post-war kitchens and baths, but not without a fight. Plumbers, who are naturally conservative folk (as befits a trade whose work is expected to last decades if not centuries), distrusted this new-fangled device and were slow to adopt it.
Moen geared up its marketing machinery and with discounts, inducements and some clever advertising targeted to homeowners, persuaded plumbers to try it. They did, and they liked it. At least in our little town, if you leave it up to the Plumber to select a faucet, you will probably get a Moen. is the other one.)
Seal and O-ring replacement is made easy because the cylinder can be removed and serviced as a unit.
Quality is determined by the materials used in the cartridge: plastic, brass or stainless — although we have not seen stainless in a Moen cartridge in a long while. Apparently, brass works just as well and is a lot less expensive. Both metals outlast plastic.
If the cylinder does develop a drip, seal replacement is a 15-minute repair using a kit available at nearly any hardware store. Or, just replace the whole cartridge. A Moen sleeve cartridge fits any Moen faucet that requires a sleeve cartridge, and with Moen's lifetime warranty, replacement cartridges are free. Just dial 1-800-BUY-MOEN or visit your local hardware or plumbing store. You may have to fill out some warranty paperwork, but otherwise, it's a no-hassle process. (To see how simple it is to replace a Moen cartridge, watch this video).
Delta Ball Valve
The ball valve was Delta's answer to the Moen sleeve cartridge. It was not, as Delta sometimes claims, a Delta invention. Landis H. Perry patented it in 1952, and Alex Manoogian, founder and then chief executive of Delta, bought the patent.
It works just like a Moen cartridge valve — in fact, it really is just a Moen cartridge disguised as a ball rather than a cylinder. But, the ball-shape was just different enough to enable Delta to squeeze around Moen's patent — much to Moen's irritation. It does improve on the Moen cartridge, however, by using rubber seals in place of the more delicate rubber o-rings in the Moen cartridge.
Rotating the handle forward and back lines up different slots to control water volume from trickle to torrent, and moving it right and left controls water temperature, just like the Moen valve.
Early ball valves were brass, current models are stainless steel and nearly indestructible. Delta boasts a failure rate of less than one in 100,000 units. But, Delta also makes a "Thrifty" ball cartridge for its low-end faucets (also used in faucets) out of plastic. In this case thrifty is not nifty. The ball is very susceptible to damage from mineral build-up that can actually score the ball, rendering it useless. It's easy to replace, but why buy the problem?
Even before Delta's patent on the ball valve expired, it was widely copied. Delta had to sue a number of other faucet companies for counterfeiting its proprietary valve. Now that the patent is expired, it is even more widely copied. The ball valve is a very simple device, so most of the copies work well. However, be aware that if you purchase a ball valve replacement from any source other than delta, there is no guarantee that it is a genuine Delta ball. And, since Delta ball valves are guaranteed for life, why would you buy a valve when Delta will send you one free of charge?
The Ceramic Disc Cartridge Valve
The response to the patented Moen and Delta washerless valves was to go its rivals one better and invent the modern ceramic disc cartridge.
The Moen cartridge seals off water flow with a number of vulnerable rubber o-rings. The Delta ball design needed just two seals, but friction against the rotating ball would eventually wear them out — especially as the ball became encrusted with sand-paper-like mineral deposits (which is inevitable in most parts of the country). Replacing them is very easy and well within the ability of any handy homeowner (See How to Repair a Leaky Faucet for a video illustration), but, obviously, eliminating all rubber in the seal would be a great advance in leak-proof technology. And, that was the advance implemented by American Standard in the ceramic disc valve.
The old, pre-breakup, was a pioneer as far back as the 1880s in the use of ceramics to make bathroom fixtures, so it seems entirely natural that it should put its industrial ceramics expertise to use to create a valve that used nearly indestructible ceramics rather than rubber to control water flow. But, evidently, the process was not as straightforward as all that.
The company, then trailing both Moen and Delta in valve technology, first looked at metal discs to control water flow. But, its engineers were suspicious of metal, fearing that it would not be robust enough for the harsh world of faucet valves and at risk of corrosion. They decided to replace the metal discs with a technical ceramic made of aluminum oxide — still the standard for ceramic discs today. After much experimentation and development, the company received patent number US 3810602 A for a "ceramic disc faucet" dating from 1972. It was a major breakthrough.
The American Standard ceramic disc valve used a pair of ceramic discs that rest against each other to control water flow. The discs are polished to near perfect flatness. The space between the closed discs is smaller than a single molecule of water, which is why water cannot flow between them when they are closed. The technology eliminated wear on rubber rings and seals and vastly extended the service life of the valve.
Ceramic discs are very hard — harder than most mineral deposits, which makes them ideal for the rough and gritty environment of a faucet valve. They resist the effects of hard water better than any other material. Fired at temperatures over 2,000°F, these discs are also unaffected by the hottest household water, unlike the rubber washers in compression faucets which can soften.
An ordinary run-of-the-mill ceramic disc valve easily lasts 5-10 years, and some super valves using diamond-like-carbon coatings are estimated to have a service life of nearly 550 years. The discs are housed in a removable cartridge which makes it simple to replace. Just pop out the worn cartridge and insert a new one.
But, ceramic cartridges are not without problems. The discs fit so close together that they are actually sticky and sometimes hard to move. To ease movement, most ceramic discs are coated with a durable lubricant. But, over time the lubricant can be scrubbed away by the friction of water passing between the discs, which makes the faucet stiffer to operate. Ceramic cartridge makers have improved lubricants over the years, searching for formulas that are more durable and last longer. But, there is a limit to this technology, and no matter how good the lubricant, the abrasive effect of water and minerals in the water will eventually wear it away. So, the next step in the ever-evolving ceramic disc technology is to eliminate the need for lubricants by making the discs slicker so they won't stick to each other.
One approach is to coat the ceramic discs with a material that is slicker and even harder than the discs themselves. Diamond-like carbon (DLC) is one such material. A thin coating deposited on ceramic discs is enough to not only improve the disc's hardness but create a very "slippery" surface that slides freely without the need for lubricant.
Types of Ceramic Cartridge ValvesCeramic cartridge valves mimic the valve technologies they are designed to replace. Single-function stem cartridges are used in place of compression valves, and dual-function mixer cartridges replace Moen sleeve and Delta ball faucets in single-handle faucets.
Single-Function Stem Cartridge (or Headworks)
The single-function or stem cartridge, sometimes call the headworks, is used with two handle faucets. It exactly duplicates the action of the older compression valve.
Each handle of the two-handle set is attached to a separate cartridge, one for hot and one for cold. Temperature mixing is accomplished by increasing or decreasing the flow of hot and cold water inside the faucet.
The cartridges are usually not interchangeable. A hot side cartridge will only fit the hot side of the faucet, and the same for the cold side. There are slight differences in how the cartridge is manufactured depending on whether it is for use on the cold side or hot side of the faucet. (For a well-done and helpful video on the difference between a compression cartridge and a ceramic cartridge, see T&S Brass Cartridges.)
Dual-Function Mixer Cartridge
A single-handle faucet uses a dual-function mixing cartridge — "dual-fuction" because it controls the temperature of the water as well as the volume of water flow. Temperature mixing occurs inside the cartridge itself before the water is delivered to the spout — just like the Moen sleeve or Delta ball cartridge it replaces. One disc, attached to the handle moves up and down to shut off or open up water flow, and left and right to align slots in the ceramic discs to allow hot and cold water to mix. The handle motion, up (or back) and down (or forward) to control water volume and right and left to change water temperature is the old, familiar Moen motion.
One easy way to telling a single function from a dual function mixing cartridge is the count the ports at the bottom of the faucet. A mixing cartridge has three, a cold inlet, a hot inlet and an outlet. A single function stem cartridge has two, an inlet and an outlet.
Ceramic Cartridge Materials
A ceramic cartridge has three main parts: the ceramic discs, a stem, and a housing or case. The stem is attached to the faucet handle on one end, and to one of the ceramic discs on the other. Moving the handle to operate the faucet moves the stem which operates the "movable" disc. The other "fixed" disc is bonded firmly to the housing. The case or housing holds all the parts together.
The movable parts of the cartridge, the stem and discs are the most susceptible to wear and damage. These need to be strong. The housing does not need to be particularly durable. In the best cartridges, the stem is brass or stainless. In economy cartridges it is plastic. Plastic is not as durable as metal and can be more easily damaged by the repeated twisting forces applied when the faucet is operated (called "torque" in engineering circles). Enough torque applied to a jammed cartridge can twist a plastic stem completely off.
A housing made of brass, aluminum or stainless steel holds up very well. These metals are, however, relatively expensive, so it did not take long for cartridge makers to start experimenting with less costly materials: primarily plastics.
Plastics used in ceramic valves, primarily poly-vinyl chloride (PVC), polyoxymethylene (POM) and nylon, are complex chemical mixtures that require very precise processing. If anything goes wrong, the result is likely to be a brittle or fragile plastic that will not hold up inside a faucet.
In the example shown in the sidebar "Autopsy of a Failed Plastic Cartridge", a minor flaw in the chemistry of the plastic allowed a thin flange to deform at the bottom of the cartridge housing. This permitted hot water entering the cartridge to continuously mix with cold water, irrespective of the position of the handle. Plastic used in cartridges is supposed to withstand the heat of household water without deforming. This one did not.
Some of the plastic used in cartridge cases is truly tough stuff. CeramTec of Luft, Germany uses an advanced plastic developed by EMS-Grivory for use in, among other places, outer space. If it will survive space, it is a safe bet that it will survive in your kitchen.
Ceramic Cartridge Manufacturing
Many faucet companies use proprietary cartridges that they often design and engineer themselves. for example, patented its first ceramic disc cartridge in the 1970s and has been improving on it since. Moen designs its own ceramic disc cartridges, as does Masco for its still uses the ceramic cartridge that it invented in 1972, and it is still a very good cartridge.
But, while faucet companies may assemble their own cartridges, we don't know of a single faucet manufacturer that actually makes its own ceramic discs. Making a ceramic disc requires technologies and expensive specialized ceramic manufacturing machinery that metal-working faucet companies don't usually own.
Ceramics are, of course, the "space age" material of the 21st century, used in everything from bullet-proof vests to Space Shuttle heat tiles. We're not sure how a material that has been around for 10,000 years has suddenly become cutting edge, but there it is. Long before recorded history some pretty good pottery was being made, and pottery, for those that don't know, is a form of ceramics.
Many of the companies that now manufacture faucet discs started out in some other areas of technical ceramics. CoorsTek, the American ceramics manufacturer founded by Adolph Coors (yes, of Coors Beer fame), makes ceramic discs used in any number of proprietary faucet cartridges but is also makes ballistic armor, ceramic insulators, automobile components and oven-safe cookware.
Roughly the same technology is used to make all technical ceramics. The main difference is the composition of the material used for each product. A ceramic disc for a faucet cartridge usually includes kaolin, feldspar and quartz or silica, but also a high proportion of aluminum oxide (alumina). The mix is shaped into a cartridge blank in a high-pressure press. The rough blanks are then fired in a furnace at a very high temperature for 18-24 hours to harden the ceramic and fuse the particles in the mix together, then cooled for up to several days. The cooled discs are finished by grinding the meeting surfaces nearly perfectly flat, and then polishing them in stages: a rough polishing followed by a second, finer, polishing and, for better discs, a third, super fine, polishing.
(For those unfamiliar with how ceramics are made, see Porcelain vs. Ceramic Tile: What is the Difference?)
The difference between good and not so good ceramic discs is the quality of the materials used and the care with which the discs are manufactured. Mixtures high in alumina produce harder discs, and alumina with a fine crystalline structure polishes to a smoother finished surface than alumina with coarser crystals. Some manufacturers add a little zirconia to the mix for even greater strength. Zirconia is very hard. In fact, fused zirconia is nearly as hard as diamonds (78 on the Rockwell B scale).
Better discs also tend to be fired for a longer period of time which fuses more of the material. The best discs are very hard, testing at 62 on the Rockwell D scale (estimated from Rockwell 45N scale score of 85), while economy discs top out at about 48. For comparison, tool steels used to make chisels and hardened drill bits usually test at Rockwell 55 to 66 (on the A or D scale), so ceramic discs are tough stuff.
For the first fifteen years of ceramic cartridge history, size and cartridge configuration were not standardized, so if a faucet maker used a particular cartridge in its faucets, it was stuck with that cartridge unless it redesigned and re-engineered its faucets to accept another manufacturer's cartridge — an expensive proposition.
Standardization began about 1980 when Galatron S.p.a., an Italian technical ceramics company, developed two basic designs for ceramic cartridges that were simple, inexpensive to manufacture and very reliable. The Galatron designs were widely copied by Asian cartridge makers like Sedal S.L.U. of China, Kuching International, Ltd., the manufacturer of the widely used KCG cartridge, and Geann Industrial Co., Ltd., both in Taiwan. Most European manufacturers followed, including Kerox, Kft. of Hungary, which manufactures the most widely used European cartridge and CeramTec which makes the popular Triduon® cartridge in Germany.
Not only has the industry settled on a de facto standard cartridge design, it has also developed more or less standard sizes. Today a faucet designed for a 35 mm cartridge can use a 35 mm cartridge from any of several manufacturers. And, faucet manufacturers have learned to mount cartridges into carriers rather than directly into the body of the faucet. Changing cartridges, then, may mean redesigning the carrier, but usually not the faucet itself, a feature that dramatically reduces tooling costs. In premium faucets like the carriers are usually brass or stainless steel, in less expensive faucets, plastic or a zinc alloy.
Standardization has been especially beneficial to smaller faucet companies that do not own their own proprietary cartridge designs or technologies. A faucet can be designed for a standard cartridge with some assurance that it can be sourced from any number of suppliers, ensuring continuing production if a supplier fails, reduces quality or raises prices. The advent of standardization, resulting in increased competition, is, in fact, one of the primary reasons why the price of ceramic cartridge valves has dropped so dramatically over the past two decades. Although, you as the retail buyer of a faucet cartridge may not notice the decrease. But, that $55.00 replacement cartridge you just bought for your $1,000.00 designer faucet probably cost the company about $7.50, down from $25.00 ten years ago.
For years the general consensus in the faucet industry has been that the best ceramic disc valves are made in Germany and Italy. That may be slowly changing, however. The Chinese ceramics industry, helped along by generous government subsidies and low-interest loans, has improved by leaps and bounds over the past two decades, and some Chinese ceramics are beginning to rival the quality of those made in Europe.
Flühs Drehtechnik, GmbH, a German firm located in Ludenscheid, Germany since 1926, world renown for its precision machining, is generally thought of as the manufacturer of the world's best single function stem cartridge. Flühs (sometimes spelled Fluehs for English speakers) valves are heavy duty products with an established reputation for leak-free reliability.
Faucet lines known to use Flühs cartridges include to name just a few.
A close runner-up to the Flühs primacy is Anton Tränkle, GmbH & Co. KG, also German, that makes superior single function ceramic cartridges out of brass for two-handle faucets. Tränkle (also spelled Traenkle for English-speakers) cartridges are used by
Some of the better European cartridges are made in Italy which boasts a well-established ceramics industry. Studio Tecnico Sviluppo e Ricerche (STSR) S.r.l., for example, makes the very good ceramic cartridges formerly used in Hydroplast, S.r.L. is another excellent Italian cartridge maker that supplies ceramic cartridges for
There is no equivalent consensus about which company makes the best mixing cartridge for single-handle faucets.
One company that does seem to be pushing itself to the forefront, and has become the cartridge of choice of many upscale European faucets is Kerox Kft, a Hungarian manufacturer that makes only mixing cartridges. Unlike Flühs and Traenkle which started as machine shops making precision turned brass parts, Kerox started as a manufacturer of dental ceramics (which it still makes), and is well known for its high-quality ceramic discs which it sells to other cartridge manufacturers, including Delta for its Diamond Seal Technology® cartridges (see more below).
Kerox is generally considered a good to excellent valve, although not as universally admired as Flühs or Traenkle. Faucets known to use this cartridge include
Sedal SA is another cartridge maker manufacturing mixing cartridges. Headquartered in Barcelona, Spain, it manufactures in China. Sedal is considered to be somewhat below Kerox quality, but still a reliable cartridge. It is popular with Chinese faucet manufacturers that make faucets for the North American market.
Geann Industrial Co., Ltd. in business over 30 years, is a well-established Taiwanese manufacturer of ceramic disc cartridges of good to excellent quality. Ten years ago the company had a reputation for good quality reliable cartridges, but nothing remarkable and nothing that made the cartridges stand out from a half dozen or so other Asian makers of good quality cartridges. That has changed. Geann is gaining recognition as a cartridge on par with many of the best European products and is becoming the cartridge of choice for faucet companies that buy their faucets from Asian manufacturers, including We are even starting to see Geann cartridges in some upscale faucet lines. for example, recently switched from Flühs to Geann cartridges for its entire line of American-made luxury faucets.
Cartridges from Weingbo Wanhai Cartridge Technology Co., Ltd. a Chinese manufacturer, are starting to attract attention. Its cartridges are frequently included in Chinese-manufactured faucets destined for the European Union where the company sells under the Quore brand from offices in Spain and Italy. We have not yet seen these cartridges in North America, but it is only a matter of time before they appear in European-made faucets.
Kuching International Ltd., a ceramics manufacturer in Taiwan since 1988 has also made its mark in the industry with its KCG cartridges popular with Canadian faucet companies including These cartridges are considered roughly equivalent to Quore and Sedal.
Some of ceramic valves are made by Maruwa (Malaysia) Sdn. Bhd and the Chinese Zhuhai Mingshi Ceramics Valve Co., Ltd. (which also supplies with some of its cartridges).
Some Asian-made cartridges are difficult to identify. Faucet companies do not generally advertise Asian, especially Chinese content. When we take these faucets apart for inspection, the manufacturer of the cartridge is usually not marked with any identifying codes, so even if the valve looks first class, we sometimes do not know who made it.
The Super Cartridges
may have trumped the traditional ceramic cartridge makers with its new Diamond Seal Technology (DST) ceramic super cartridge. One disc in the two-disc set is diamond coated using a process that creates microscopic diamond pyramids on the disc.
Delta says the diamond coating helps keeps the discs absolutely smooth since the coated disc continuously polishes the other disc so they always mesh perfectly. It also continuously grinds away any mineral deposits that may insinuate themselves between the discs. The more you use it, the smoother it gets, says Delta which claims that the cartridge will last up to 5 million uses (or about 700 years in the average kitchen faucet, 20 to 30 times the lifespan of a standard ceramic cartridge). But, if you ever need to change the cartridge, Delta has a video for that, which you can view here, and the replacement is free from Delta to the original owner for the owner's lifetime.
The DST technology is available in most better Delta and nearly all Brizo faucets. Delta's plan is to eventually equip its entire lineup of faucets with the new cartridge.
Delta's is not the only super technology in use, however. Another proven approach is to coat both ceramic discs with a material that is very slick and also very hard. One of these is diamond-like-carbon (DLC), one of the hardest materials known to man (hence the "diamond-like" in its name).
As an example of how hard it is, stainless steel coated with DLC just two microns thick resisted abrasion in laboratory tests 4,000 times longer than uncoated steel (1 week vs 85 years).
A very thin (measured in microns) coating deposited on the cartridges using physical vapor deposition (PVD) technology is enough to not only improve the disc's hardness but create an exceptionally "slippery" surface that slides freely without the need for lubricant.
Faucets known to use DLC coating on their ceramic discs include which includes a super mixer cartridge made by Kerox, Kft in all of its single-handle faucets. Some cartridges made by Flühs Drehtechnik, GmbH use as similar technology.
In2aqua estimates that its proprietary PVD+™ DLC-coated discs will last 10 times longer than uncoated discs. Based on independent laboratory tests that estimate may be a little on the conservative side. After putting the discs through 4 million consecutive off/on-hot/cold cycles over 90 days, they showed no observable wear. Four million cycles are equivalent to about 550 years of use in an average home kitchen. We think the odds are very good that PVD+ discs will operate for the entire lifetime of the faucet without replacement.
Lubricant-free cartridges require better materials, more exacting manufacturing and some additional steps to ensure that the ceramic discs slide freely, and are more expensive, but they are generally more durable, longer lasting cartridges, and well worth the modest additional cost.
Which Valve is Better?
Which valve is better? That's a question that can start a three-hour argument among the pros we know, and really cut into Miller time.
You probably cannot get most plumbers to install a traditional compression-type faucet without an argument. But, that may depend on the valve. Most plumbers, especially the old-timers, like quarter-turn compression valves. Still, there are plumbers who would not use a compression valve if it were given a life-of-the-universe guarantee by the Almighty Herself.
But, homeowners in love with everything vintage won't use anything else. While compression and Fuller faucets need washer or ball replacement every few years, it's not very hard to do. If done regularly (so the valve seat is not damaged), the faucet valve will last nearly forever. And, even if the valve is damaged, it takes very little effort to hone it smooth again (although a special tool, available at any plumbing store, is required). We regularly see faucets made in the middle of the 20th century still in use and still functioning perfectly after nearly 100 years.
ball valves last a long time. The rubber and plastic seals will eventually wear out after 5-10 years, but replacing the seals is a job well within the capability of any homeowner who can handle a screwdriver without doing irreparable harm.
Ceramic disc valves can last nearly a lifetime with virtually no maintenance. They are replaceable when they finally fail (and they will — eventually). Repair is easy. The old cartridge is just thrown away, and a new one inserted. It's all done at the top of the faucet, not underneath the countertop. The longest we have ever taken to replace one of these is about 10 minutes. Ceramic disc cartridges with plastic stems do not seem to last as long as those with metal stems — and it does not appear to make any difference which metal: stainless, brass and aluminum. Some very inexpensive cartridges will last just two years, but 5-20 years is more typical.
On the whole, with some exception, we give a slight edge to ceramic disc cartridge technology. It is the newest and in many ways the best technology, and it just keeps getting better. Even Delta and Moen are shifting to it as fast as they can. We think ceramic cartridges are just a little tougher and seem to give a little less trouble. But, we certainly will not discount Moen or Delta proprietary valves. They have a track record second to none for longevity and reliability.
Style and configuration may dictate your valve decision. Single-handle faucets cannot use compression valves. And, availability may well affect your decision. Compression valves in faucets for home use are fast disappearing from the market. As far as we can tell, only the companies still making commercial faucet still use a compression-style cartridge in their faucets.