Why Is the HVAC Industry Switching to A2L Refrigerants?

To understand why HVAC systems are shifting towards A2L refrigerants, we need to grasp two key concepts: Ozone Depletion Potential (ODP) and Global Warming Potential (GWP).

  • Ozone Depletion Potential (ODP): Measures the potential of a refrigerant to harm the ozone layer.
  • Global Warming Potential (GWP): Measures the impact of a refrigerant on global warming relative to carbon dioxide (CO₂).

Historically, the industry has gone through several phases in refrigerant selection, driven by the need to reduce both ODP and GWP:

  • CFCs (Chlorofluorocarbons): High ODP and high GWP. Examples include R12 and R11.
  • HCFCs (Hydrochlorofluorocarbons): Lower ODP but still high GWP. Examples include R22 and R123.
  • HFCs (Hydrofluorocarbons): Zero ODP but high GWP. Examples include R410A, R134a, and R32.
  • HFOs (Hydrofluoroolefins): Zero ODP and very low GWP. Examples include R1234yf and R1234ze.

With the EPA HFC phase-down act, the HVAC industry is shifting to refrigerants with zero ODO and lower GWP. The two main low-GWP refrigerants now being adopted are:

  • R32: Primarily used in Daikin and other new HVAC systems.
  • R454B: Being adopted by Trane, Lennox, and other major manufacturers.

Both R32 and R454B are classified as A2L refrigerants, meaning they have no toxicity (A class), low flammability (2L class) and low GWP. For HVAC service technicians, these two refrigerants are becoming the industry standard, aligning with environmental regulations.

Why Are NAVAC’s Current HFC Leak Detectors Compatible with A2L Refrigerants?

A common question arises: if the leak detector is designed for HFCs but not HFOs, can I take it as A2L compatible?

First, let’s look at the composition of these two mainstream A2L refrigerants:

  • R32: Made entirely of difluoromethane, an HFC with zero ODP and a GWP of 675, meeting the EPA’s GWP threshold of 700.
  • R454B: A blend of 68.9% R32 and 31.1% 1234yf (an HFO). The dominant component is still R32, an HFC.

Since NAVAC’s leak detectors are designed to detect HFC refrigerants, they are fully capable of detecting A2L refrigerants like R32 and R454B, which have high HFC content.

However, it is important to clarify that this does not mean the leak detector can detect all A2L refrigerants. If a leak detector does not detect HFOs (Hydrofluoroolefins), it may not be able to detect A2L refrigerants that are composed primarily of HFOs or blends containing more than 50% HFOs. For a comprehensive understanding of the compatibility of the NAVAC NML1 Leak Detector with specific A2L refrigerants, please refer to the “ASHRAE A2L Refrigerants” spreadsheet attached to this article.

In conclusion, if you are an HVAC technician, your current HFC leak detector will be suitable for most of your daily tasks involving A2L refrigerants like R32 and R454B. However, if you are an automotive technician working with HFO refrigerants such as R1234yf or R1234ze, you will need to use a dedicated HFO leak detector for accurate detection.

Types of Leak Detectors and Which Is Best for A2L Refrigerants

There are two main types of leak-detecting sensors used in the HVAC market:

  1. Infrared (IR) Sensors
  2. Heated Diode Sensors

While infrared sensors are newer and often marketed as advanced, they are not always superior. Each technology has its own advantages and drawbacks:

Infrared (IR)
Advantages: Stable readings; Long Sensor life
Disadvantages: Higher cost, may not detect all blends

Heated Diode
Advantages: Fast response; High sensitivity
Disadvantages: Shorter sensor life, more maintenance

A common misconception with Heated Diode sensors is their use of heated elements, leading to the misconception that they may not be safe with A2L refrigerants due to flammability. However, this is a misunderstanding. The operational temperature of these sensors is far below the ignition point of any A2L refrigerant:

Thus, NAVAC’s HFC leak detectors are not only capable of detecting A2L refrigerants, but they are also designed to operate safely without the risk of igniting these refrigerants.

Experience the NAVAC Difference 

As the HVAC industry moves towards low-GWP, A2L refrigerants, it is essential for service technicians to use compatible leak detectors. NAVAC’s current HFC leak detectors are already designed to meet these needs, offering reliable detection for both traditional HFCs and the new A2L refrigerants like R32 and R454B.

For more information on other A2L compatible NAVAC Tools, visit https://navacglobal.com/a2l-compatible-tools/.