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In 1938 Paul Symmons (Symmons Industries, Inc.) invented the first pressure balanced shower valve was born and with it a revolution was at hand. At the time of its inception unreliable water pressure was the rule not the exception so having a shower valve that could smooth out those inconsistencies was invaluable. After more than half a century there have been many tweaks and improvements to the pressure balanced/thermostatic mixing valve however I think it’s best if I give a brief summary of how each of these valves work.
Pressure Balance Shower Valve
Scald protection and thermal shock are two terms that are used together and can overlap. Scalding can cause thermal shock which can then result in a fall or any number of injuries resulting from the shock of being scalded or blasted with ice cold water. How many of us have accidentally jumped in the shower just a few seconds before the hot water kicks in and nearly slipped and fallen?
A pressure balance valve is a valve that protects against these types of issues by regulating the amount of pressure within the shower valve.
Pressure balance valves come in two varieties.
- The first is a diaphragm type, this valve has the hot coming from one side and the cold from the other, the balancing disk is in the middle. The disk slides back and forth on a piston. Changes in pressure push against the disk and move the piston in the direction of the lower pressure and cuts off flow from the high pressure side.
- The second in the spool type pressure balance valve, it has a spool inside the valve, the spool slides towards the supply with the lower pressure. This cuts off the volume of water entering the valve on the high pressure side and allows more water from the low pressure side. Output water temp cannot vary more than 3 degrees. ASSE Code 1016 defines scald protection valves. Both valves do not adjust for fluctuations in temperature.
Thermostatic Mixing Valve
This valve adjusts volume of water and protects the user by sensing water temperature. The most common type of thermostatic mixing valve has a paraffin wax element that expands and contracts based upon the supply temperature. If the wax gets hot the spool slides over to pinch off the hot side and vice versa. This type of valve is usually both temperature and pressure balanced.
There is another type of thermostatic mixing valve that uses a bi-metal strip. As the temperature changes so does the shape of the metal. As the metal changes shape it adjusts output temperature. As you can imagine a piece of metal that is constantly expanding and contracting can become brittle and eventually break. It’s one the reasons the wax element type valve has become the norm.
Some of the changes that have been to each of these valves from all manufacturers have been seating materials. In the early days of thermostatic and pressure balanced mixing valves the seats were usually made of leather of rubber. However it didn’t take very long to figure out that these type of seats could and would wear out. It was at this point that the progressive manufacturers began experimenting with other materials. The advent of metal on metal seats was and still is one of the most popular types of valve seats.
Even though metal on metal seats work great and last for some time they are not without their issues. Shower valves are made of bronze or brass alloy and these types of metals tend to be somewhat soft relatively speaking. With continuous opening and closing these metal seats can become pitted or worn and eventually they will wear out.
The last improvement that’s been made in seating material was the introduction of ceramics. The use if ceramic seats and seals makes those valves almost indestructible. In fact most times the valve itself will fail before the seats and seals.
The only problem with the shower valve either pressure or thermostatically regulated is that very little else has been improved. How is the valve installed? How can the valve be tested? How is the valve repaired if there happens to be an issue? And lastly what if you want to upgrade the valve and or trim once it’s been installed? Most of us plumbers have the perfect answer for that “you can pay me to rip out the old and pay me to install the valve of your choice”. Although that is a fair answer from a plumbing contractor who bases their business on remodel and repair it’s also irresponsible for the same contractor to be ill informed on the choices that are out there.
Delta came out with the Multi Choice several years ago but it’s versatility is limited however the one valve that addresses most of the issues stated above is the Hansgrohe Ibox valve. The first thing you’ll notice, other than the valves Hulk green valve case are the four full 3/4″ ports to accommodate most rough-in configurations.
What if the water piping is 1/2″? Do I have to buy extra fittings to accommodate the valve? Nope, the 3/4″ x 1/2″ bushings are included in the box.
The Ibox valve itself is protected against leaking at all its connection points in fact the entire valve is sealed by the green enclosure. If there is a leak within the valve or the connection points the valve will leak into the box and exit through a weep hole on the front of the trim kit.
The next point of interest are the valve’s integral stops. Hansgrohe has made the rough-in valves affordable enough to remove the option, you get integral stops standard.
There are other benefits that we will list but by far the greatest feature is the valves flexibility. It is a pressure balanced shower only valve (the plug for the tub is included in the box), it is a pressure balanced tub/shower valve, it is a thermostatic valve with volume control for a shower, a thermostatic valve for a tub/shower and thermostatic valve with volume control with a diverter to control two shower functions.
How can one shower valve to handle all these features? With the trim and cartridge. It’s a “plug and play” valve. You can get a trim that is simple and affordable or opt for a fairly complex trim set with a full line of styles and finishes. If you wanted to install an affordable trim set but wanted to upgrade at a later date the install is quick and easy. Oh and did I mention regardless of the trim set you get ceramic disc cartridges?
If you are looking to build a home or upgrade a bath give the Hansgrohe IBox valve a look. Other companies have tried to make a similar product but none has perfected it like Hansgrohe.