Pressure Switch Symbol Types

Gas Water Heater Air Pressure Switch Application

Pressure Switch Symbol Types

High-Pressure Switch Symbol

The high-pressure switch symbol is one of the pressure switches. The pressure switch is a high-pressure switch and a low-pressure switch. Now we will learn about the high-pressure switch.


What Is A High-Pressure Switch

A high-pressure switch is a discrete sensor that, rising pressure, can run the switch to open or close. The specified pressure setpoint varies with different devices.

Usually, A high-pressure switch has two circuits connect types: NO (Normally Open) high-pressure switch and NC(Normally Closed) pressure switch.

Pressure Switch Symbol Types

High-Pressure Switch Symbol

Symbol A from the image is an NC switch in the following pictures. When the pressure rises, it will cause the switch to open. This symbol A is an NC high-pressure switch symbol. Symbol A shows the lever above the contact terminals. If the pressure is too high to above the specified setpoints, the switch will open and shut off the pump, adding pressure to the system.

Symbol C from the image is an NO switch. When the pressure rises, it will cause the switch to closed. The symbol C is a NO high-pressure switch symbol. Symbol C shows the lever above the contact terminals. If the pressure drops to the setpoint, the switch will close, and the compressor tank will add pressure to the system, so the high switch will be applied in the compressor tank to maintain the pressure inside.


Low-Pressure Switch

A low-pressure switch is a small device that will open or close a circuit of the system only

when the pressure value drops to a mini setpoint pressure. The low-pressure switch is one of the pressure switches. You may widely use it in the pressure safety system.

Pressure Switch Symbol Types

Low-Pressure Switch Symbol

The low-pressure switch can be divided into NO(Normally Open) low-pressure and NC(Normally Closed) low-pressure switches. The symbol of the low-pressure switch also is different from another.

Symbol B from the image is an NC pressure switch. In symbol B, you can see that the switch lever is below the contact terminal. The low-pressure switch is widely used to monitor the oil pressure. If the oil pressure drops to a safe pressure lever, the switch will change to the open state, and the system will stop running. This is a whole running process of a low-pressure switch!

Symbol D from the image is a NO pressure switch. A low-pressure switch usually lets the switch arm below the contact terminal from the pictures. When the pressure rises to a high-pressure lever, the switch will close the circuit and widely appears in the motor starting!

So the high-pressure switch lets the switch arm lever above the contact terminals, but the low-pressure switch lets the arm below the contact terminals. The two kinds of pressure switches have NO types and NC types.


Global Electrical Pressure Switch Symbols Standard

Reference the industry standard, here are the following standard regarding electrical pressure symbols:


  • IEC 60617 (also known as British Standard BS 3939).
  • NFPA / JIC. Also adopted by the NMTBA (National Machine Tool Builders Association).
  • ANSI Y32.2-1975 (also known as IEEE Std 315-1975).
  • IEEE Std 91.


You can also learn more knowledge about different global standards on Wikipedia.

Learn more about Limit Switch Symbol.


Order Air Pressure Switches Product 


Pressure Switch Symbol Types


Unionwell Micro switch China Manufacturer: Years Of Professional R&D Team 

Our unionwell manufactures and develops microswitch solutions and conducts product evaluations for our customers in an actual startup state. In this way, our customers will trust us that the switch will work in the car they design before it is shipped. We also provide application design services to support our customers during the design phase.

Huizhou Unionwell Sensing & Control Electronics Co., Ltd specializes in quality micro switches for the automotive industry and white goods of home appliances. Main products include basic micro switches, waterproof switches, air pressure switches, mechanical keyboard switches, and door switches.

For better guarantee on pricing, lead time, and quality control, we acquired Huizhou Greetech Electronics Co., Ltd in 2021. We made it our China production base with over 1000 employees and a 260 million pieces/year production capacity.

Huizhou Greetech is an ISO9001, IATF16949 and ISO14001 certified micro switch manufacturer whose complete series of products have been granted global access permit certifications, which include ENEC, UL, CE, CB, etc.

Now, Our global reach covers North America, Europe, Asia, and South America.

Most of our business partners/end customers are Global 500 enterprises, including world-famous home appliance brands and leading automotive suppliers in North America and Europe.

Shortly, we are launching a new industrial base at Longmen, Huizhou, Guangdong Province; automation equipment will be introduced, which would massively improve the switch production capacity from 260 million pieces to over 1.3 billion pieces/year. 

A one-stop system will be built, covering product development, precision molding, injection molding, precision stamping, automated equipment R&D, assembling, and testing. 

The professional sales team is on hand to provide assistance and quick response to 3D drawing requests, price quotes, and access to an effective sample program that allows engineers to test and qualify switches for their end product applications.


Core Value:

Goal, Responsibility, Coordination, Innovation

Effort, Development, Openness, Integrity


Our Mission:

We are obligated to maintain long-term relationships that stand the test of time.


Our Vision:

To become a first-class global manufacturer of precision components and modules.


Related Product Link:

waterproof micro switch product

Share this post