Pressure Valve, Definition, Functions and How it Works

Pressure valves play an important role in regulating and protecting the temperature in various Heating, Ventilation, and Air Conditioning (HVAC) devices. Insight into these devices is essential, including if there are hot water pipes in your home and business premises. This information is even mandatory for anyone who relies on HVAC equipment as a business object.

What Is a Pressure Valve?

A pressure valve is a special valve for temperature regulation for various purposes. This includes maintaining consistent temperature in certain rooms and controlling the water temperature at the tap according to needs. The high demand for HVAC equipment is supported by technological developments, resulting in various types of devices that can be adjusted to suit needs.

Benefits of Using a Pressure Valve

The use of a pressure valve must suit your specific needs. However, in general, this device comes with various benefits. This includes accurately regulating the temperature according to needs, both in air and water. This is closely related to the safety of consumers who use this device in everyday life.

You can feel the benefits of using a valve when a water heating device is installed in the bathroom. When the heating system is activated, you can regulate the flow of hot water to a particular tap, and not flow into the bathtub or toilet pipes. The risk of scalding from hot water will be kept under control due to the presence of a safety valve.

Types of Pressure Valves According to Needs

One of the characteristics of the best product is when it is used according to needs. Of course, you have to choose the most efficient, guaranteed, and affordable product. But the suitability of the product to business needs is the most important because you will use it in the long term.

After finding a reliable supplier, let’s immediately select the pressure valve based on its type. Procurement of HVAC equipment must start by identifying your specific needs, and then adapt it to the products available on the market. Please identify the features, how it works, and other descriptions by looking at the following overview.

Valve Type	Main Function	Typical Application	Key Parameter to Check
Temperature and Pressure Relief Valve (TP Valve)	Prevents excessive temperature and pressure buildup	Boilers, water heaters, pressure storage	Opening/resetting temperature, pressure rating, DN size
Fan-Coil Component Valve	Heats and cools rooms without air ducts	Fan coil units, HVAC zoning systems	Applicable media, max glycol percentage, operating temperature
Dynamic Balancing Valve	Limits flow rate and stabilizes system balance	Hydronic heating circuits, HVAC distribution	Flow rate setting, pressure differential range
Freeze Protection Valve	Prevents pipe blockages from freezing	Outdoor pipework, heat pump systems, cold climates	Opening/closing temperature, material compatibility
Scald Protection Valve	Limits hot water temperature at the point of use	Bathrooms, care facilities, households with children	Protection temperature, material (brass), max pressure

Temperature and Pressure Relief Valve

This tool can prevent excessive temperature and pressure with an automatic seal-opening wax inspection system. These protective devices are usually installed in boilers, water heaters, or in controlled pressure storage areas. The best products should ideally be able to reset automatically to prevent wasting hot water resources under certain conditions.

Procurement of TP relief valve must consider a number of technical parameters. A good product must have clear information about opening and resetting temperature. You also have to get clear information about the pressure rating, resetting pressure, water-touching metal materials and DN size. Also consider the product’s expansion rating and standards compatibility.

Fan-Coil Components

The main function of this device is to heat and cool rooms without air ducts. This valve is installed as part of a fan coil system — which consists of a coil, fan, and condensation device — so that the temperature setting for each zone is accurate as needed. As part of a pressure valve, there are several technical parameters that are important in procuring this device.

After appointing a credible supplier, you should get transparent information about applicable media, for example for use in water pipes and for ethylene glycol solution. The next important information is the maximum glycol percentage, working pressure, and operating and ambient temperature range.

Dynamic Balancing Valve

This pressure valve functions as a flow limiter, especially preventing flow rates that are too large. The valve will close when the flow rate is potentially large and will open again when the flow is stable. With this tool, users can maintain the flow rate stably and according to the desired settings.

Freeze Protection Valve

The next type is a safety valve to prevent blockages due to freezing. Its function is dynamic, including for the liquid sugar industry and other thick liquids. The flow in the system is susceptible to blockage due to freezing at certain temperatures. By opening and closing the system in the right situation and time, the flow will continue to flow to prevent the freezing of the system.

Pipeline systems often suffer from water freezing problems in long winters. This device can overcome freezing which results in flow blockages when the water temperature drops. The device starts work by opening a valve to drain water out of the pipe when temperature falls to the opening threshold — as low as 1.6°C — and reaches full open at 4°C. The valve will close again automatically once the water temperature recovers above 7°C, restoring normal pipe operation. For more detail on how this valve works, you can read our article on freeze protection valve function and working principles.

Scald Protection Valve

This pressure valve plays an important role in ensuring hot water delivery meets a safe minimum temperature at the point of use. Rather than limiting high temperatures, it works as a minimum temperature guard: the valve remains closed when water is below the safe delivery threshold and opens progressively as temperature rises — beginning to open at 36.7°C and reaching full open at 43.3°C. This prevents lukewarm water from being delivered to the user, which is important both for comfort and for hygiene requirements such as Legionella control in solar and storage hot water systems.

Procurement of scald protection valve must take into account several technical parameters. Among other things, you have to choose the right material, for example, brass. Also check the information about the initial open, full open, and full close temperatures. Product selection must also be accompanied by adjustments, regarding information on working temperature, max pressure, and others.

Apart from the types of pressure valve products mentioned above, there are many other types with specific functions. These include Water Return System Control Valve, Dynamic Flow Balancing Valve, and Pressure Limiting Valve. These devices support the safety and energy efficiency of HVAC systems.

“One mistake buyers often make when procuring pressure valves is focusing only on price per unit rather than the full parameter set. A freeze protection valve with the wrong opening temperature can let a pipe freeze before it ever activates. A scald protection valve with inadequate flow tolerance can restrict water pressure to the point where it becomes inconvenient. When reviewing products, I always tell our partners: read the full technical datasheet, confirm the opening and closing temperatures match your system’s operating conditions, and ask the supplier what happens when the valve reaches the end of its thermal cycling life. That conversation tells you a lot about how seriously the manufacturer takes their product.”
— Maggie Shen, Founder of Legom

Pressure Valve Supplier

There are many product choices for pressure valves with special specifications. If you are still confused about determining which one best suits your needs, do not hesitate to consult with the pressure valve supplier before actually making a transaction. So you can get the best recommendation. You also do not hesitate to ask for information about product specifications to suit your business needs.

You can get the complete information about pressure valves by contacting Jiaxing Legom Technology Co., Ltd. We are an experienced HVAC valve manufacturer and supplier in China. We have a proven good business reputation. Our company is ready to serve your needs in the field of procurement of HVAC products, and various mutually beneficial partnerships.

Frequently Asked Questions

Frequently Asked Questions

What is the difference between a pressure relief valve and a scald protection valve?

A pressure relief valve, specifically a temperature and pressure (TP) relief valve, is designed to protect the entire heating system by releasing pressure and preventing dangerous overheating in boilers and water heaters. A scald protection valve operates at the point of use and functions as a minimum temperature guard — it ensures that water delivered to the user is adequately hot, closing when temperature drops below the safe delivery threshold and opening as temperature rises. Both are safety valves, but they protect against different risks at different points in the system.

When is a freeze protection valve necessary?

A freeze protection valve is necessary whenever a pipeline system is exposed to temperatures that could cause the water inside to freeze. This is common in outdoor pipework, heat pump circulation systems, and pipes running through unheated spaces such as roof voids or external walls. In cold climates, these valves are considered standard installation practice. The valve activates automatically when the water temperature drops to the opening threshold, draining water from the pipe to prevent ice formation, without requiring any electrical input or manual intervention.

What parameters should I check before buying a pressure valve?

The key parameters vary by valve type. For TP relief valves, check the opening and resetting temperature, pressure rating, resetting pressure, and DN size. For scald protection valves, check the initial open, full open, and full close temperatures, material (brass is standard), working temperature range, and maximum pressure. For freeze protection valves, check the opening and closing temperatures and material compatibility with your pipe fluid. For dynamic balancing valves, check the flow rate setting range and pressure differential specifications. Always request a full technical datasheet from the supplier before ordering.

Is scald protection valve installation mandatory?

In many countries and regions, scald protection valve installation is required by plumbing codes or government regulations, particularly in healthcare facilities, aged care homes, and schools where vulnerable users including children and elderly people are present. The specific requirements vary by country and building type. In residential settings, it is not always legally required but is strongly recommended as a safety measure. Always check your local plumbing code and consult a licensed plumber to confirm the requirements that apply to your specific project.

Can Legom supply pressure valves for international projects?

Yes. Legom supplies pressure valves and HVAC valve products to partners in more than 90 countries through a network of over 400 business partners. Products are available with international certification and in specifications suited to different regional standards and system requirements. OEM services are also available for companies that need products supplied under their own brand. Contact Legom’s technical team to discuss your specific valve requirements, quantities, and delivery options.

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Reviewed and updated by the LEGOM Technical Team on May 26, 2026. This article covers the main types of HVAC pressure valves including TP relief valves, fan-coil component valves, dynamic balancing valves, freeze protection valves, and scald protection valves, along with their functions, applications, and key procurement parameters, based on Legom’s experience as an HVAC valve manufacturer supplying solutions to partners in more than 90 countries worldwide.