Types of Shower Valves and Controls

Shower Head Spraying Water
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Once more of a novelty in homes, the shower has become increasingly important as a means to warm up, cool off, and get clean in a hurry. Not surprisingly, as the demand for showers grew, so too did the options for how showers were built.

Modern showers have two different types of temperature control valves as well as diverters for multiple component systems and either digital or manual control systems.

Temperature Regulating Valves

While showers are relatively easy to install, they have a major drawback. Water comes from a shared source, causing the temperature to fluctuate, sometimes dramatically, when another tap or toilet draws hot or cold water. Without some form of temperature regulation, water may suddenly become too hot or cold if a nearby toilet or sink is used.

For this reason, two advanced types of valves were introduced to replace traditional valves that actively regulate your shower’s temperature.

Mechanical or Pressure-Balancing Valves

Sometimes referred to as mechanical or anti-scald valves, this type takes advantage of the difference in pressure created by sudden temperature changes. Once you have turned the water on and adjusted it to your desired temperature, the system works to keep the water at that temperature.

In the event someone flushes the toilet or uses the sink, the sudden rise or drop in temperature causes a pressure change within the valve. This causes the valve to shift and re-balance the pressure, preventing injury.

It should be noted that this valve works by adjusting the amount of pressure and not the temperature itself. As a result, the flow of water from your shower head may increase or decrease when water is diverted to other appliances.

Additionally, pressure balancing valves are not always a good idea when remodeling an older home, as corrosion in the pipes may affect the efficiency of your valve. Having the pipes pressure tested prior to purchasing the valve will help prevent post-installation issues.

Thermostatic Valves

A more expensive alternative to pressure balancing valves, the thermostatic valve is designed to maintain both pressure and temperature. Another advantage to this option is the ability to preset water temperature before turning the water on, allowing you to hop in without first waiting for the water to heat up or make multiple small adjustments to get the temperature just right.

Traditional Mixing Valves

The mixing valve functions just as the name implies. Its simple function is to draw water to the shower head from the hot and cold taps. Depending upon the control system, this may be as simple as a central knob that diverts water from your tub’s tap, or a single knob on standalone showers.

Found mostly in older homes, mixing valves are no longer popular and can be dangerous, as they cannot regulate sudden changes in water temperature. This puts the person showering, especially the elderly and children, at risk of being scalded when someone flushes a toilet or the washer changes cycles.

Diverters and Transfer Valves

When dealing with anything more complicated than a simple shower, you will need a diverter to direct water between the components. These control the water direction, but not the temperature and are used in conjunction with thermostatic or pressure-balancing valves.

Diverter Valves

Diverters come in three different options. Tee diverters are the most basic type and consist of a simple pull arm located on the tap. Once the water has reached a comfortable temperature, you pull the arm up which blocks the tap, redirecting water to the shower head.

A second type is the three-valve diverter. This variation allows you to adjust the hot and cold water individually, then turn a central knob 180 degrees to divert the water between shower and tap. The major difference between this and the third type, the two-valve diverter, is that the latter uses a single rotating control for hot and cold and a second control to divert water between the shower and tub.

Transfer Valves

While diverters switch the flow of water between a tub and shower, transfer valves allow for the flow of water to be sent to multiple outlets at the same time. These systems are ideal for shower walls or running a handheld shower head without turning off the main shower.

While transfer valves generally only allow you to use one or two components at a time, some valves allow for more than two components. In these valves, the setting will activate one or a combination of two components at a time, but cannot run all three at once.

Digital Controls

Digital control panels may be the option of choice when you want full control over the shower without the clutter of manual knobs. The controls allow a wide range of programmable options, giving a more personal experience that requires very little fiddling to reproduce every time.

Aesthetics

The control is a single digital panel, taking up less space than manual controls. In addition, the panel will not have the same corrosion issues as metal handles. Multiple component systems may be controlled by a single panel, making even less clutter.

Temperature Settings

The panel allows you to set a precise temperature for the water. Once you have that perfect temperature, you can program it into one of the user presets. These controls may also be set to warm up, pause, or run on a timer. More complex controls may include additional options such as steam settings.

Manual Control Systems (Trim)

Manual trim is found in most bathrooms. These are the knobs which control water temperature as well as divert water in a tub/shower combo.

Bath/Shower Trim

This combination trim is perhaps the first thing you think of when picturing a shower. Most commonly, the trim consists of separate knobs or handles for hot and cold water, as well as a diverter control. The diverter allows you to switch the water between the tap and shower head.

Shower Trim

A shower trim is used for standalone showers. While control variations allow for multiple components, water is generally sent straight to the shower head. The most basic variation of this trim option is a single knob or handle which is pulled or raised to turn on the water and rotates left and right to adjust the temperature. The downside to this type of control is that many models do not allow you to control the volume of water coming from the shower head.

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