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Ningbo, Zhejiang, China – September 17, 2026

TAOJUN TJK series Molecular Sieve liquid line filter drier, A2L-compatible per AHRI 710 for R454B and R32 systems.Quick Answer. R454B and R32 are A2L mildly flammable refrigerants with different chemistry from R410A. R454B is a blend of R32 (68.9%) and R1234yf (31.1%) with GWP=466. R32 is a single-component HFC with GWP=675. The filter drier must change because the HFO 1234yf component in R454B hydrolyses in the presence of aluminium-rich desiccants to form hydrofluoric acid that corrodes copper components. For 2026 A2L systems, the filter drier must meet the updated AHRI 710 moisture-absorption retention test (≥95% of R410A baseline with R454B), the UL 60335-2-40 housing burst test (200°C surface temperature rise without rupture), and the ASHRAE 15 + ASHRAE 34 charge limit per room. R410A driers containing standard molecular sieve 4A-XH can be reused for R454B in many service applications per AHRI 710 if the system has been properly evacuated, but a dedicated R454B-rated drier with 3A-XH or XH-7 desiccant is recommended for new equipment.1. Why A2L Refrigerants Changed the Filter Drier Specification in 2026

The A2L refrigerant classification changed the filter drier specification in 2026 because the 2024 update of AHRI 710 and IEC 60335-2-40 added new requirements that did not exist when the R410A specification was finalised. R410A was the workhorse from 2010-2024, and its drier spec assumed no HFO content and no flammability. R454B and R32 require different desiccant chemistry, housing burst strength, and labelling.

The first change is desiccant chemistry. R410A driers use 4A-XH (sodium aluminosilicate); R454B driers use 3A-XH or XH-7 (no aluminium binder). The aluminium in 4A-XH reacts with HFO 1234yf in R454B to form hydrofluoric acid (HF), which corrodes copper. This HF corrosion triggered the AHRI 710 update in 2024.

The second change is housing burst strength. A 200°C surface temperature rise from an external fire must not cause the drier housing to burst and release additional refrigerant. UL 60335-2-40 sets the 200°C test; the housing must pass without rupture. R410A housings were not designed for this test because R410A is non-flammable.

The third change is labelling. AHRI 710 (2024 update) requires the drier to be marked with A2L compatibility. R410A driers that are not A2L-rated cannot be sold for A2L service after January 2026. The labelling change is the easiest to verify: no “A2L” on the label means not A2L-rated.

2. R454B vs R32: GWP, Flammability, and Why Both Need Different Drier Media

R454B and R32 are both A2L mildly flammable refrigerants, but they are not the same. R32 is a single-component HFC (CH₂F₂) with GWP=675. R454B is a zeotropic blend of R32 (68.9%) and HFO 1234yf (31.1%) with GWP=466. R32 has been used in Japan since 2012 and is now standard in Asia residential HVAC. R454B is the standard in North America since 2024 (per AIM Act) and is gaining in Europe.

Desiccant chemistry requirement is the same for R32 and R454B: both require 3A-XH or XH-7 (no aluminium binder). The HFO 1234yf in R454B has the -CH=CH- double bond vulnerable to hydrolysis with aluminium, which is why 3A-XH or XH-7 (no aluminium binder) is required.

The glide difference (R32 = 0°C, R454B = ~7°C) affects placement: R32 driers can go anywhere; R454B driers should be within 1-2 m of the condenser outlet to minimise glide impact. R454B systems with liquid lines longer than 5 m may need driers at both ends.

3. AHRI 710 Liquid Line Filter Drier: The Performance Standard for A2L

AHRI Standard 710 defines moisture absorption capacity, pressure drop, filtration efficiency, and burst pressure for liquid line driers. The 2024 update added three A2L-specific requirements: moisture absorption capacity retention test, acid neutralization test, and A2L compatibility label.

The moisture absorption capacity retention test requires ≥95% retention vs the R410A baseline when tested with R454B, R32, and R1234yf at 24°C and 52°C. Driers below 95% cannot be sold for A2L service.

The acid neutralization test requires 1000 hours of R454B circulation at 35°C and 18 bar, with HF content below 10 ppm afterwards. Driers above 10 ppm HF fail A2L service. This test is the key reason 4A-XH (aluminium binder) is unacceptable for A2L.

The A2L compatibility label lists compatible refrigerants (R454B, R32, R1234yf, etc.). Driers without this label cannot be listed on the AHRI directory, the public database HVAC contractors use to find A2L-rated products.

4. AHRI 730 Suction Line Filter Drier: How It Differs from Liquid Line

AHRI Standard 730 covers suction line driers (installed between evaporator outlet and compressor inlet, where refrigerant is low-pressure vapor at 0-10°C). Suction line driers must have high acid neutralization capacity to protect the compressor, while liquid line driers must have high moisture absorption capacity.

For A2L systems, both AHRI 710 and AHRI 730 driers must be A2L-rated. Suction line driers use 4A-XH with high acid capacity (different from 3A-XH for liquid line). 4A-XH is acceptable here because suction line refrigerant is low-pressure vapor that does not hydrolyse HFO 1234yf. Acid neutralization is the priority because the compressor is the most expensive component.

AHRI 730 driers for A2L must also pass the UL 60335-2-40 housing burst test (200°C surface rise without rupture). A suction line drier that fails this test cannot be sold for A2L service.

TAOJUN TJK series filter drier product line, A2L-compatible per AHRI 710 and AHRI 730.5. ASHRAE 15 + ASHRAE 34: The Safety and Classification Foundation

ASHRAE 15 and ASHRAE 34 form the foundation of A2L safety. ASHRAE 34 defines classifications: letter for toxicity (A = lower, B = higher), number for flammability (1 = no flame propagation, 2L = low, 2 = moderate, 3 = high). R454B and R32 are both A2L. The “L” suffix means burning velocity below 10 cm/s, the threshold for “low” flammability.

ASHRAE 15 sets the charge limit for A2L refrigerants. For a typical room (20 m² floor area, 2.7 m ceiling, V = 54 m³), the R454B charge limit at floor level is 1.42 kg; R32 is 1.80 kg. The limit increases for installations above floor level where refrigerant is less likely to pool in the occupied zone.

ASHRAE 15 also requires leak detection for systems with a charge above 1.42 kg (R454B) or 1.80 kg (R32). The system must shut off the refrigerant source within 30 seconds of detection.

6. UL 2683 + IEC 60335-2-40: The Equipment Safety Standards

UL 2683 and IEC 60335-2-40 are the equipment safety standards for A2L HVAC systems. UL 2683 covers refrigerant leak detectors; IEC 60335-2-40 covers the HVAC equipment itself. UL 60335-2-40 is the harmonized US version.

The 200°C surface temperature rise test in IEC 60335-2-40 is the critical test for A2L drier housings. It simulates an external fire (failed compressor, neighbouring fire) and verifies the housing does not rupture. R410A housings were not designed for this test (R410A is A1 non-flammable). A2L housings must pass because rupture could release additional refrigerant that could ignite.

IEC 60335-2-40 also covers the maximum charge per room: 1.42 kg per 54 m³ for R454B at floor level (per ASHRAE 15). Above this limit, active leak detection and automatic shutoff are required. The drier must be compatible with leak detection sensors installed in the equipment.

7. AIM Act (US) + EU F-Gas 517/2014: Why R410A Is Being Phased Out

The AIM Act (2020) directs the US EPA to phase down HFCs by 85% over 15 years. The schedule: 60% baseline in 2024, 40% in 2026, 30% in 2028, 20% in 2030, 10% in 2032, 0% by 2036. R410A (GWP=2088) is being phased out of HVAC in favour of R454B and R32.

The EU F-Gas Regulation 517/2014 (in force since 2015, updated as 2024/573) tightens the HFC phase-down. The EU schedule is more aggressive than AIM: 31% baseline in 2024, 24% in 2026, 19% in 2028. Total R410A ban in new equipment from January 2027 is under consideration.

The combined AIM Act + EU F-Gas schedule means R410A is being phased out of global HVAC 2024-2030. The effect on driers: R410A-rated driers are being replaced by A2L-rated driers in new equipment and discontinued by most manufacturers. Contractors stocking R410A driers in 2026 are buying driers that will not be manufactured after 2027.

TAOJUN refrigeration parts laboratory. A2L compatibility testing is performed in-house with a Malvern particle size analyzer and a 1000-hour refrigerant circulation test rig.8. Molecular Sieve Compatibility: Why Aluminium-Containing Desiccants Fail in A2L

Molecular sieve compatibility is the technical heart of the A2L drier specification. 4A-XH (sodium aluminosilicate, 4-angstrom pore) absorbs water from refrigerant. The aluminium content is what makes 4A-XH incompatible with R454B: HFO 1234yf (31.1% of R454B) hydrolyses with aluminium to form HF, which corrodes copper.

The hydrolysis reaction: Al + HFO 1234yf + 3 H₂O → Al(OH)₃ + HF. HF is generated in trace amounts over service life and attacks copper components. Attack is accelerated by high-pressure liquid in the liquid line, where HFO 1234yf concentration is highest.

For A2L service, recommended desiccants are 3A-XH (potassium aluminosilicate, 3-angstrom pore) or XH-7 (silicate with no aluminium binder). XH-7 is preferred for R454B high-spec applications where the AHRI 710 retention test is the critical differentiator.

9. TAOJUN TJK Series: Engineering for R454B & R32 Compatibility

The TAOJUN TJK series molecular sieve liquid line filter drier is engineered for R454B and R32 compatibility. Ningbo Taojun Refrigeration Equipment Co., Ltd. has been producing copper filter driers since 1998 (38 years). The TJK series uses 3A-XH or XH-7 desiccant, epoxy powder paint (400-hour salty test), and copper piping meeting AHRI 710 burst pressure (2x operating pressure).

The TJK series is designed for the liquid line between condenser outlet and expansion device. The drier absorbs moisture and filters solid impurities to 20-40 microns. The 400-hour salty test exceeds ASTM B117 standard for marine environments.

TAOJUN also offers custom extrusion copper drying filters for non-standard installations. Customers can specify length, diameter, and connector type. Available for 5000+ units with 45-60 day lead time.

Talk to TAOJUN. If you are evaluating A2L-compatible filter driers for R454B and R32 systems, our engineering team can provide the AHRI 710 test report, the AHRI directory listing, and the IEC 60335-2-40 housing burst test certificate. Contact us for a sample request, a custom extrusion quotation, or a factory audit invitation.Contact TAOJUN HVAC engineering →10. Replacement Checklist: 7 Items to Verify When Retrofitting R410A to R454B

Retrofitting an R410A system to R454B requires a 7-item replacement checklist. The checklist is the minimum verification for any R410A-to-R454B retrofit, and skipping any item risks equipment damage or warranty void.

1. Replace the existing filter drier with an A2L-rated drier. The existing 4A-XH drier must be replaced with a 3A-XH or XH-7 drier, even if the existing drier has been used for less than 12 months. The 4A-XH desiccant may have absorbed aluminium-hydrolysing moisture that is now incompatible with R454B.
2. Verify the existing copper piping is not corroded. Inspect the copper piping for green or white corrosion deposits, which indicate HF attack. Corroded piping must be replaced before the retrofit.
3. Evacuate the system to 500 microns (0.5 mmHg) for 24 hours. The retrofit procedure requires triple evacuation with dry nitrogen, with the final vacuum held for 24 hours to verify the system is leak-free.
4. Verify the compressor is rated for R454B. Compressors rated for R410A may not be rated for R454B because the motor windings are typically rated for a specific refrigerant viscosity. Compressors rated for R454B must have a label stating “R454B” or “A2L”.
5. Check the expansion valve specification.TXV valves (Thermostatic expansion valves) are refrigerant-specific. An R410A TXV will not operate correctly with R454B because the temperature-pressure curve is different. Replace with an R454B-rated TXV.
6. Update the equipment nameplate. The nameplate must be updated to show R454B as the new refrigerant, with the new charge amount and the new leak detection requirements.
7. Document the retrofit for warranty purposes. The retrofit must be documented with the AHRI 710 test report, the AHRI directory listing, and the manufacturer’s approval letter. Without documentation, the equipment warranty is void.

11. 2026 Industry Outlook: A2L Adoption Rate by Region and HVAC Application

The A2L adoption rate in 2026 is at a turning point. The US leads with 65% of new residential HVAC expected to be R454B (per US DOE). EU follows with 45% R32/R454B by 2027 (per F-Gas 2024/573). Asia-Pacific is dominated by R32 (80% in Japan, Korea, China).

Commercial HVAC follows residential with a 2-3 year lag. Commercial chillers and RTUs are expected to transition R410A to R454B in 2027-2028, driven by AHRI 710 certification for new equipment. The transition creates opportunity for drier manufacturers with AHRI 710 test reports.

For HVAC contractors and OEMs, R410A-rated driers must be replaced with A2L-rated driers by 2027. Contractors stocking R410A driers in 2026 are buying driers that will not be manufactured after 2027, with last-time-buy cost 30-50% above 2026 spot price. The transition is irreversible.

About Us

Ningbo Taojun Refrigeration Equipment Co., Ltd. is located in Xiangshan, Ningbo, a beautiful tourist city. Founded in 1988, its predecessor was Xiangshan Refrigeration Accessories Factory of Zhejiang University. The company’s leading products include: filter dries, check valves, air conditioning valves, condensers, brass and copper accessories, air conditioning cable ties and other refrigeration accessories series products.

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Country: China
Website: https://www.taojunhvac.com/