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What is a Thermostatic Valve?

Charity Delich
Charity Delich

A thermostatic valve is a device that works behind the scenes to help achieve a desired temperature. It can be used for a range of purposes, such as maintaining a consistent temperature in a room or controlling the temperature output of water from a faucet or showerhead. There are several different types of thermostatic valves including mixing valves, shower valves, and radiator valves.

A thermostatic mixing valve is an apparatus that combines hot and cold water in order to produce a consistent temperature output. Mixing valves are often used to help regulate the delivery temperature of stored water, ensuring a safer and more comfortable water supply. Consider, for example, that most large-scale water supplies are stored at a temperature of 140°F (60°C) or greater in order to ensure that harmful bacteria is eliminated. A mixing valve helps prevent scalding or freezing water from spewing out when this stored water is released. Mixing valves are also often used to regulate temperatures in showers, sinks, and bathtubs.

A thermostatic valve can be used to help keep the water coming from a faucet at a consistent temperature.
A thermostatic valve can be used to help keep the water coming from a faucet at a consistent temperature.

A thermostatic shower valve is a type of mixing valve which can be essential when it comes to bathroom plumbing. For example, if a person is using the shower and a toilet is flushed or another faucet is turned on, the water temperature could change dramatically. As a result, the person in the shower could be scalded by hot water or shocked by cold water. The use of a shower valve helps eliminate these kinds of drastic changes in temperature.

A thermostatic valve can prevent burns due to sudden fluctuations in water temperature.
A thermostatic valve can prevent burns due to sudden fluctuations in water temperature.

Alternatively, some shower systems use pressure balanced valves, also called anti-scald valves. While a pressure balanced valve system is usually less expensive than a thermostatic valve system, a thermostat valve typically provides better temperature regulation. As with a thermostatic valve, a pressure balanced valve helps regulate incoming hot and cold water supplies. It does this by immediately regulating any variations in water pressure, even when outlet pressure decreases. Most home construction codes require builders to install either a thermostatic valve or a pressure balanced valve.

Without a thermostatic valve, a person is using the shower and a toilet is flushed or another faucet is turned on, the water temperature could change dramatically.
Without a thermostatic valve, a person is using the shower and a toilet is flushed or another faucet is turned on, the water temperature could change dramatically.

Thermostatic radiator valves are typically used in hot water or steam radiator heating systems to help maintain a steady temperature in a room. They can experience variations in temperature depending on whether other heat sources, such as light streaming in from a window, are present in the room. As a result, they are usually used in buildings that do not require an exact temperature to be maintained.

Installing a thermostatic mixing valve on a home hot water system may help prevent scalding injuries.
Installing a thermostatic mixing valve on a home hot water system may help prevent scalding injuries.

In general, a thermostatic radiator valve consists of a valve that controls the hot water flow and an actuator that regulates when the valve opens. As a room grows warmer, the valve restricts the flow of hot water. Conversely, when the room cools, the valve allows more heat to be distributed into the room.

Discussion Comments

Cageybird

There is nothing worse than a thermostatic valve failure during a shower. In my experience, the water almost always becomes scalding hot. The same thing has happened with the kitchen sink's faucet. I'll be washing dishes with warm water and suddenly the water will become steaming hot. I have one of those faucets where the water temperature is controlled by a single central stem, not two separate hot and cold knobs.

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    • A thermostatic valve can be used to help keep the water coming from a faucet at a consistent temperature.
      By: Elenathewise
      A thermostatic valve can be used to help keep the water coming from a faucet at a consistent temperature.
    • A thermostatic valve can prevent burns due to sudden fluctuations in water temperature.
      By: Ariwasabi
      A thermostatic valve can prevent burns due to sudden fluctuations in water temperature.
    • Without a thermostatic valve, a person is using the shower and a toilet is flushed or another faucet is turned on, the water temperature could change dramatically.
      By: LukaTDB
      Without a thermostatic valve, a person is using the shower and a toilet is flushed or another faucet is turned on, the water temperature could change dramatically.
    • Installing a thermostatic mixing valve on a home hot water system may help prevent scalding injuries.
      By: OlegD
      Installing a thermostatic mixing valve on a home hot water system may help prevent scalding injuries.