Different Types Of Valves Used In HVAC: Complete Guide


An HVAC system is a central system that manages the premises’ heating, ventilation, and air conditioning.

This system comprises different valves used to maintain the pressure and materials within the system to keep the flow adequate.

One of the most important things is choosing the suitable valve, which is a very tricky decision even for the technicians who are experts in this regard.

So, to make the proper selection, you need to know several things to make the right decision.

Here in this guide, we have provided detailed insight into these HVAC valves, allowing you to make the right decision when choosing them.

So, let’s read below and get to know all the essential details in choosing the HVAC valves.

Video – Types of HVAC/R Service Valves, How They Work, Port Access & Problems!

What is an HVAC System?

HVAC stands for Heating, Ventilation, and Air Conditioning.

These are centralized systems and have valves that control the flow of water, steam, and gasses flow through them, either for cooling or heating purposes.

The different types of HVAC systems consist of chillers, furnaces, heating pumps, boilers, and air conditioning units.

The essential thing in these systems which control their function is the valves present, as they keep the system running smoothly.

Why Does an HVAC System Need Valves?

The HVAC system works by moving the inside with the help of pipes.

These pipes are responsible for either heating the air up or cooling it down.

The pipes are also responsible for eliminating the humidity from the air.

This air, either in the cooled or warm form, is then released into the space, which may be a house or other premises.

The essential part of the HVAC system is the furnace, which occupies the major space inside this system.

The furnace then uses different sources for heating purposes; this will include the heat pump, solar energy, and sometimes electric resistance too, and the heat is produced.

On the other hand, when it comes to the cooling process, the furnace comprises another unit, the evaporator, which contains coil-based funnels that tend to transport the cold air in the surroundings.

Apart from the furnace, other essential components inside the HVAC system may handle the air purifiers, dehumidifiers, and ventilation.

General Types of Valves Used in HVAC

Many kinds of different valves may be used in the HVAC system, which is discussed below in detail.

Control Valves

A control valve is designed to manage the steam and fluid in contrast with the pressure and flow.

This valve has a controlling system operated via a power-based device and receives a signal from the controller to manage the function.

In the cooling systems operated in industries, the control valve plays a significant role.

It has the task of managing the temperature, pressure, and liquid level within the accurate range so it can operate properly.

There are various kinds of control valves present in HVAC systems, and some of the common ones are as follows:

1. Rotary control (ball and butterfly valves)

There are two kinds of rotary valves: the ball and butterfly valves.

However, in these valves, the fluids are moved around the passages inside, and this passage is created in the rotating style.

The rotator valves are usually very flexible and compact, followed by the sufficient capability to be used in various applications. They even can allow heavy fluids to pass through them.

2. Linear control (globe and diaphragm valves)


In a linear valve, there is a push mechanism that leads the flow of the liquid.

It is a very slow process, but the outcome is very stable, and the design of a linear valve is also very long-lasting.

There are two kinds of linear control valves: globe and diaphragm valves.

3. Three-way control

Stainless Steel 3 Way Clamp Ball Valve with Actuator

The three-way control valve has two different configurations and comprises a mixing and diverter valve.

These valves use two pipes, where one pipe opens the flow of fluid, on the other pipe closes the flow.

This kind of valve controls the different fluids like oil, water, and steam in the HVAC units and is commonly observed in boilers, water chillers, and fan coils.

4. Self-acting control

In the self-acting control valve, the water flow is controlled and regulated.

The fluid in this kind of valve is temperature-sensitive; when it is heated, it expands, whereas when it is cooled, it contracts.

The force generated by the expansion and contraction either opens the valve or closes it.

This kind of valve is commonly used in engines used in industries, air compressors, boilers, and chillers.

These valves work independently and don’t need any external power; they are durable and easy to install.

Check Valves


Check valves use the mechanism of pressure to function.

These automated valves let one liquid flow and block the passage of the other liquid.

When the pressure on the inner area of the valve is more than that of the oyster area, it closes the valve and vice versa.

The HVAC systems use this kind of valve so that the fluid direction is controlled, which is done to eliminate the presence of a water hammer.

Double Block And Bleed Valves


Double block and bleed valves are commonly used to control the flow of fluids and carry out maintenance purposes.

This kind of valve isolates one of the streams.

If it opens downstream, the flow on the upstream is isolated, and if it lets the upstream open, the flow of fluids is stopped downstream.

This kind of valve controls the process flow in the HVAC system for the process fluids.

In these valves, the operational portion is distracted from the equipment and other components like different gauges it has.

The valve comprises the two blocks, and the air is trapped between the blocks and is released by the bleed assembly.

Pressure Relief Valves

Pressure Relief Valves

Pressure relief valves are such valves that are dependent on the pressure within them.

They open or close when the pressure inside their fluid system is very high.

The compromise of balls or diaphragms, and there is an adjustable spring.

As the pressure on this spring increases, the pressure limit of the valve also changes.

These are only applicable in industrial and commercial HVAC systems and not everywhere.

Balancing Valves


Balancing valves are common and comprise measurement equipment that monitors the pressure loss across the valve.

The HVAC system uses this kind of valve in the evaporator outlet of the chillers.

These valves also provide a report detailing fluid flow in the different systems.

Butterfly Valves

Butterfly Valve

Butterfly valves are not just used in HVAC systems; there are many applications of such valves.

They are usually found in chillers, boilers, cooling towers, bypasses, and many other applications.

They use the liquids in contrast with the bubble-tight shutoff and are a common kind of valve found in commercial and industrial applications.

Ball Valves

3PC Stainless Steel Flanged Ball Valve

The ball valves give a very economical use and help save the cost of energy with their excellent mechanisms.

These are used in different cooling systems as well as HVAC.

They are very lightweight and compact and follow the rotary control mechanism.

Float Valves

In an HVAC system, the float valves cater to various purposes, and in industrial plants, these are also responsible for managing water levels.

Apart from this, they control the temperature of a surrounding premise.

These valves are incredibly reliable and very easy to install, so they are suitable for controlling water flow.

Pressure Independent Balancing Control Valve

Pressure independent balancing control valve, also known as PICV, is an automatic valve.

It controls and regulates the fluid flow rate automatically, adjusts it, or keeps it constant depending on the pressure conditions installed in the circuit.

It is commonly used for cooling purposes and is used in HVAC systems.

Motorized On/Off Valve

The motorized on and off valves are such valves that either allow the flow of water or completely stop it.

They regulate the coil units, and this is done based on the signals of the thermostat.

These valves are relatively inexpensive and are commonly used for cooling in a small capacity because they have smaller units.

These valves are also quite flexible and versatile and even compatible with all cooling and heating systems brands.

Air-Vent Valve

The air vent valve automatically relieves the air from the pipeline.

If there are air bubbles in the pipelines, the water is not effectively pumped, and hence it is essential to install an air vent valve to get rid of these bubbles and let the water pass.

Similarly, when it comes to the HVAC systems, the valves used are manufactured using cast-iron material on the outer part, and the inner is made with such materials which are highly resistant, like stainless steel.

Since the inner part of these valves is filled with water at all times, the inner might rust, so the material needs to be chosen carefully.

The air vent in such systems consists of a float ball, and in the absence of the air bubble, it collects the water.

As soon as the air bubbles fill inside, the ball moves away and lets the bubbles leave, and the float ball returns after this process.

Gate Valve

Stainless Steel Flanged Gate Valve GB PN16

The HVAC systems also consist of another valve, the gate valve, which turns clockwise and anticlockwise with a wheel at the top.

The movement either opens the water flow passage or shuts it down.

These valves are suitable for smaller isolation, whereas, for larger isolation, butterfly valves are more suitable.

These gate valves used in HVAC systems are manufactured using bronze.

Such valves are quite common in air handling units and chilled water pipes.

How To Choose an HVAC System Valve?

After you have gone through the details regarding the HVAC valves and their mechanisms above, you must now consider how to choose the appropriate value for your system.

Each kind of valve has a different purpose, so you must choose the correct option.

Here we have shared specific details about these valves and their selection tips that might be very helpful for you, and these are provided below:

  • Type of Flow

The type of flow that will be passed through the pipe is one of the most important things to consider when choosing a valve.

It depends upon what you will be letting pass, whether solid, liquid, or gas, and similarly, when it is pressure gassed, the metal valve proves to be a suitable choice.

On the other hand, if you choose any corrosive material, you might need to have some valve with PTFE or PFA.

  • Movement and Positioning of Valve

The first thing you need to decide when choosing a valve is whether you need an automated or manual one.

Also, the position it takes once the power is withdrawn from it.

If you are choosing an actuator that has a double-acting mechanism, it will keep its last position intact.

If you invest in the spring actuator, it will either remain closed or open once the signal has been lost.

  • Installation of the Valve

The valve you choose will have its management system; each kind of valve will have a different kind of system.

So, you must know that system, what kind of monitoring and control it supports, and how easy it is to connect the valve or disconnect it when needed.

  • Maintenance Required

Some valves are easy to clean and maintain, and some require extensive maintenance.

So, by opening up the kind of valve you have chosen, you need to assess what is more suitable for you and what is more accessible.

How To Check the Quality Of HVAC Valves?

When choosing the correct valve, it is essential to assess its quality, and here we have shared specific points that allow you to check the valves’ quality.

  • Continuously monitor the temperature control and position of the valve over time.

  • Check for any leakage.

  • To assess the temperature, you must first close the valve and wait so the temperature stables. After this, check the temperature on each side of the coil; it must be the same to be the right quality.

  • Inspect the stem gland of the valve to check if the valve is weeping. If it is, you should look for a replacement.

  • There must not be any corrosion on the valve’s body because corrosion signals the improper selection of material for the valve’s body.

  • Inspect the valve bonnets to check if any faulty mounting is apparent on the actuator.

  • You can also inspect your valve with a listening device that allows you to listen to all kinds of rattling sounds so that you may assess its quality. If any such rattling exists, you should look for another valve.

How To Choose the Right HVAC Valve Manufacturer?

It could be very challenging to choose the proper manufacturer for the valves of HVAC.

Here are some tips that could help you make your manufacturer selection easier:

  • First, always look for large inventory maintenance on the manufacturer’s part. This will allow you to have your choice of valve for emergencies well. If the valve you need is present from that manufacturer, you will be able to complete your HVAC system and save time.

  • The manufacturer you choose must also offer spare parts for maintenance and repairs.

  • You should also consider the response and after-sales services of the manufacturer in case of any problem or query.

  • The valve company must also offer you the actuators and valves because an actuator is essential for a valve to work effectively.

  • The valve manufacturer must use innovative methods and expertise to instantly manufacture the latest valves that bring ease to the HVAC systems.

If you are looking for the proper valve manufacturer, we at INOXCN can provide a wide variety of stainless steel valves to choose from, which are from the finest quality material and offer various functions.

We are always ready to cater to you with the right ideas as to which material and type of valve will suit your HVAC system.

So get in touch today and have the accurate valves chosen for your systems.

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