Essential Knowledge for Refrigerants and System Upkeep

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Refrigerant Basics and System Maintenance: Myth vs. Fact

MYTH: So called "drop-in" alternatives can be mixed with R-22

FACT:

Never top off a system using one refrigerant with a different replacement refrigerant, as mixing refrigerants is not recommended. The original refrigerant should be recovered using appropriate equipment and managed according to U.S. EPA guidelines specified in Section 608 of the U.S.Clean Air Act. If the two refrigerants have different safety classifications, new safety hazards could also be introduced.

Supporting Resources:

EPA-Stationary Refrigeration Service Practice Requirements

EPA- Refrigerant Management Requirements
MYTH: Refrigerant blends with flammable components will always be flammable.

FACT:

Non-flammable blends commonly used in the industry have flammable components for example R-410A, MO99 (R-438A), R-407A, NU22B (R-422B), but are designated as non-flammable (Class 1) by ASHRAE.

Supporting Resources:

UN/ASHRAE: Update on New Refrigerants Designations and Safety Classifications
MYTH: All refrigerants are created equal
FACT:

Even refrigerants with the same "R-number" from various suppliers may not be of the same quality. Random testing of refrigerants from various suppliers has shown that commercially available products do not always meet AHRI purity, composition, moisture or air standards. Always purchase refrigerants from a trusted and proven supplier.

Supporting Resources:
- Dr. Chuck Series: Refrigerant Quality & Why It Matters
- Risks of Low Quality Refrigerants
MYTH: HFOs can only be used in new equipment
FACT:

Many HFOs and HFO blends have been used extensively for both system retrofit and/or new equipment. The determining factor on whether or not a refrigerant can be used in existing systems vs. only new equipment is based on the safety designation. There are several HFOs and/or HFO blends with an ASRHAE Class 1 (non-flammable) designation, which have been used successfully in field retrofits as well as new equipment.

Supporting Resources:
MYTH: All R-22 Replacements require an oil change
FACT:

While pure HFCs like R-407C require a full oil change from mineral oil to POE when converting away from R-22, "mineral oil compatible" replacements have been successfully used for decades. Hundreds of thousands of R-22 air conditioning systems have been successfully retrofitted to Freon™ MO99 (R-438A) and Freon™ Nu-22B (R-422B) while continuing to run on mineral oil.

Supporting Resources:
MYTH: You can know everything you need to about energy efficiency by comparing refrigerants
FACT:

To understand and compare the efficiencies of a new HVACR system, you need to consider the design, components, refrigerant used and the operating conditions. No one factor will determine the energy consumption. When retrofitting systems and only changing refrigerant fluids, it can be reasonable to compare performance on the basis of the refrigerant properties themselves. However, when comparing different fluids that will be used in distinct system designs and/or under different operating conditions, this comparison becomes less consequential. Whether talking about cooling capacity, energy efficiency ratings, or environmental impact, the total system footprint determines the outcome. "Selection of refrigerants and their systems must be based on a holistic analysis including energy efficiency and performance attributes, environmental impacts, employee and public safety, and economic considerations. A refrigerant should not be selected based on any one single factor such as GWP, operating pressure, flammability, etc."

Supporting Resources:
- ASHRAE: Position Document on Refrigerants & Their Responsible Use