Understanding Shower Valves and Trim

Heather Asiyanbi - 9/6/18 11:00 AM

Your shower may seem simple, but it has a lot of working parts you’ll need to master in order to get it up and running. Whether you’re remodeling or starting from scratch, understanding shower valves and their trims will help get you started.

How Does a Shower Work

Before we can begin exploring the parts of a shower, it’s vital to know how a shower works.

When you turn the handle on in your shower, the shower pulls in water from the water main or your well. This water increases in pressure as it passes through the water meter and then splits into two streams.

Cold water immediately heads to your shower, while hot water heads to the water heater first, which is why showers always start off cold. Then, the hot water joins the cold in the pipes behind your shower wall. Your shower valve controls how much of each passes through depending on the set temperature.

The water is pushed through to the showerhead or another area if you have a diverter installed (like a tub faucet or body sprays).

Clearly, the valves and trim play an essential role in your working shower.

Understanding Shower Trim

Many people prefer to start with the trim before they decide and install shower valves.

The trim is the handle and the piece of metal which controls both the operation and temperature of your shower.

Single handle shower trims are the most popular because, in many states, two handle trims are not allowed. With a dual handle trim, one handle controls the hot water while another controls the cold. If the cold is never turned on, hot water temperatures can be dangerous and scald you. Single handles always have some cold water being mixed with hot to prevent scalding.

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Manual shower trims still dominate the market, but digital trims are growing in popularity. Digital shower trims have greater precision, control, and customization than a manual shower; however, their price point is much higher.

The last thing you’ll need to consider before purchasing trim is your shower type.

A standalone shower requires just a shower head and shower faucet trim, but you can also add components like hand showers, rain shower heads and body sprays. You can either purchase every piece individually or purchase a kit, ensuring that everything matches. When the trim and shower head are sold together, the sets are called shower faucets. If you are installing a shower/bathtub combo, you’ll need a bath spout with a diverter, a shower head and a manual trim.

Understanding Shower Valves and Their Functions

Shower valves are responsible for the amount of water flowing, the temperature of that water, and turning the shower on and off. They connect the shower trim to the water pipes.

Valves are brand specific. If you’ve already chosen your trim, make sure the valve you purchase is the same brand. If you’re remodeling, and you will not be replacing the valve, your new trim will have to match the valve's brand. When searching for a new valve, inquire about the spec sheet and the product description. The valve trim type should be noted in that information.

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Some shower valves also contain a diverter. A diverter controls which aspect of a shower uses water and when.

The default is to push water towards the shower head, but this can be adjusted if you have other faucets, shower heads or body sprays. Most tub faucets come with a diverter, but it’s important to double check. Other pieces, like body jets, require a diverter and an additional diverter handle outside the wall.

Two Types of Manual Shower Valves

Pressure-Balancing Valves

For a basic shower or tub set up, pressure-balancing valves work perfectly.

They are all-in-one solutions that allow you to turn the shower on and off, as well as control water temperature within one handle. This is the set up you’ll find in most showers.

You set a new temperature every time you take a shower and the valve handles both the temperature as well as the water pressure.

Finally, additional transfer and diverter valve options allow you to expand the number of components you can control with pressure-balancing valves.

Thermostatic Valves

A thermostatic valve is a step up from a pressure-balancing valve.

Temperature and volume controls are different, which means you can set a temperature once, and the valve will always keep that temperature shower after shower. You can also add separate volume control valves to adjust the flow of each component in your shower like shower heads, hand showers, and body sprays.

This type of valve takes showers to the next level.

The Success of Your Shower

How successful your shower installation is depends on the knowledge and research you put into your shower.

Make sure your trim and valves match, or your shower will never work. Also make sure you add a diverter or use a valve with a built-in diverter if you need one.

When all the pieces work together, you can enjoy a wonderful shower every time you step under the spray.

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Topics: Shower- Bathroom

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