Factors for Choosing the Right Pressure Transducer for Ammonia Refrigerant Systems

This article was originally published on September 23, 2023, and updated on November 3, 2025. 

As the HVAC/R industry continues to reduce greenhouse gas emissions, ammonia has become a preferred natural alternative to traditional chlorofluorocarbon refrigerant compounds. Ammonia's low environmental impact and high efficiency make it an attractive choice—but only when used with properly selected components. Because ammonia is corrosive to certain materials and can be hazardous at high concentrations, every part of your system, including pressure transducers, must be carefully matched to its demands.

As a product director specializing in pressure sensors for 30 years, I know what to look out for when it comes to selecting an OEM pressure transducer for applications dealing with refrigeration and ammonia. Read this article to learn why ammonia remains a leading refrigerant choice, what challenges it presents, and which four factors to consider when selecting a pressure transducer for ammonia applications. Factors include accuracy, material compatibility, process connections and approvals/certifications.

Why is ammonia a popular refrigerant choice?

Ammonia has been used as a refrigerant for more than a century—and for good reasons:

Ammonia is environmentally friendly

Data published by American Society of Heating, Refrigerating and Air‑Conditioning Engineers (ASHRAE) and other organizations show ammonia is a natural refrigerant that has zero ozone depletion potential (ODP) and a negligible global warming potential (GWP). Since ammonia does not contribute to greenhouse gas accumulation or global temperature increases like CO₂, it is considered one of the most sustainable refrigerants in use today.

Ammonia is energy efficient

Because of its excellent thermodynamic properties and high latent heat of vaporization, ammonia absorbs and transfers heat efficiently—leading to lower energy consumption, making it highly energy efficient as a refrigerant.

Ammonia has a broad temperature range

Ammonia performs well in both high- and low-temperature applications, making it suitable for a wide range of industrial and commercial cooling systems. This makes it a versatile choice for different industries and applications.

Ammonia is cost effective

Compared to synthetic refrigerants, ammonia is widely available and relatively inexpensive, reducing operational costs for businesses using ammonia refrigeration systems.

Ammonia has safety protocols in place

While ammonia is classified as a toxic substance, it has been used as a refrigerant for over a century and has established safety protocols in place. Properly designed and maintained ammonia refrigeration systems can be operated safely, and industry standards ensure the safety of workers and the surrounding environment.

What are the concerns of using ammonia as a refrigerant?

While ammonia offers significant performance and environmental advantages, it also presents challenges that must be carefully managed. In certain quantities, ammonia can be hazardous to people and animals, so systems must be properly designed and monitored to prevent leaks or accidental release.

Ammonia is also chemically incompatible with many materials commonly used in large refrigeration systems—particularly copper and copper alloys such as brass and bronze. Exposure can cause corrosion, leading to leaks or containment failures. To prevent these risks, all wetted components, including pressure transducers, should be constructed of compatible materials such as stainless steel to ensure long-term reliability and safety. Failure to do so could result in component failure and a containment breach. To ensure Use Ashcroft's online material selector tool to identify compatible materials for your application.

What are the factors for selecting a pressure transducer for ammonia systems? 

Selecting the right transducer helps protect your instruments from ammonia exposure, ensuring stable and accurate pressure measurement in demanding refrigeration environments. Consider the following four factors when evaluating your options.

1. Accuracy

Finding a transducer that meets the accuracy requirement of an application can be difficult. This is because there are no industry standards when it comes to stating the accuracy of a pressure transducer. Accuracy is often noted as a percentage of the full span of the device and consists of these main components:

• Non-linearity
• Hysteresis
• Repeatability
• Zero Offset
• Span offset

Several Ashcroft pressure sensors, including the use our proven Chemical Vapor Disposition (CVD) technology that helps maintain reliability and accuracy across mid- to high-pressure applications. Watch video to learn more. 

2. Material compatibility

All wetted parts of the pressure transducer must be compatible with ammonia. Stainless steel (such as 316L) is the preferred material because it resists corrosion and degradation from ammonia exposure. Always verify material compatibility in the manufacturer’s datasheet or consult your supplier before installation.

Most reputable suppliers list the material makeup of the wetted components such as the diaphragm and socket of the transducer on their datasheet so you can verify the compatibility of these materials in your application. As stated earlier, you can also refer to Ashcroft's material compatibility tool on our website. 

3. Process & electrical connections

Choose process and electrical connections suited to your system’s design and environmental conditions.

Process connections can vary in type from male and female tapered threaded connections like NPT or BSPT style threads to straight treads like SAE fittings designed for low-pressure automotive and refrigeration applications to special high-pressure fittings made for applications from 10,000 psi and up.

Electrical connections can vary from those with lead wires or a short run of cable exiting the back end of your transducer to a wide selection of specialized connectors like M12, Deutsch®, Metri-Pack® or DIN connectors.

When choosing the proper electrical connector, consider:

• The number of wires you need to install the transducer into your application
• Ease of wiring and connection
• The appropriate ingress protection (IP) rating for your environment

Proper selection ensures safe installation and reliable signal transmission in demanding refrigeration systems. If have any questions about whether a particular process or electrical connector is right for your application, contact your supplier for additional information.

4. Approvals and certifications

Refrigeration and industrial systems often require transducers that meet specific safety and performance standards. Look for:

• General safety approvals governed by agencies like UL
• Refrigeration-specific approvals that are governed by agencies such as UL, CSA, ETL and NSF
• Hazardous location approvals such as flameproof/explosion-proof, intrinsically safe, non-incendive and increased safety, which are governed by approval agencies such as FM, UL, CSA, ATEX and IECEx.

Compliance with these certifications confirms the device meets recognized industry standards for safe operation in ammonia refrigerant environments.

There are also product certifications that suppliers can use to self-certify the product, or third-party agencies that can verify products meet the requirements of these certifications. These include Safety Integrity Level (SIL), CE and Restriction of Hazardous Substances (RoHS).

In the end, suppliers should be able to provide certificates or documentation backing up the approvals they list on their website or datasheet.

Ready to learn more?

After learning about the benefits of using an ammonia refrigerant and the four factors to consider when selecting the right pressure transducer for your specific needs, I want to underscore one primary point: when used properly, ammonia and related compounds can be a safe, highly efficient refrigerant that doesn’t release harmful substances into the environment.

However, if the systems using it aren’t configured safely, ammonia can cause equipment malfunctions and harm to operators. Now that you understand the concerns about selecting pressure sensors, you can conduct a more targeted search for the specific transducers you need.

Ashcroft has several pressure transducer options available for ammonia refrigerant applications. The E2  transducer family model  E2G, for example, was designed for challenging applications and made with all-welded 316L stainless steel, which is resistant to ammonia’s corrosive properties.

 For applications that require additional hazardous location approvals such as FM and ATEX, Ashcroft offers the E2 transducer family models E2S and E2F.

If you are looking for a mid-to high-volume, cost-effective option that can also meet ammonia refrigerant requirements, try the Ashcroft® G3 pressure transducer that uses all welded 316L stainless steel wetted parts.

For more information about pressure transducers in applications with strict requirements? Check out some of our other related articles:

Choosing the Right Pressure Sensor: 5 Factors to Consider

How Accurate Are Your HVAC System’s Pressure Instruments?

How Are Pressure Transducers Affected by Hydrogen Permeation?

If you’d like to learn more about selecting the right pressure sensor, download 5 Mistakes OEMs/System Integrators Make When Selecting Pressure Sensors.

Or, feel free to contact us today to talk to one of our industry experts and get your questions answered.