by Rick Kincel
The Wild West has come to HVAC retrofit and “service”
Many contractors are doing whatever is easiest to get a job done while not necessarily thinking through the
bigger picture of who they may be hurting or putting at risk.
R-410A should not be used in an A2L-optimized compressor because doing so may compromise system
performance, reliability, and safety margins.
It can hurt the contractor; It’s Illegal
Installing an A1 refrigerant, such as R-410A, into a system rated for an A2L is illegal by the UL Standard
60335-2-40, ASHRAE Standard 15/34, and the EPA and is inconsistent with the system’s approved design and
rating and also mixing classifications or cross-retrofitting violates federal SNAP rules and equipment listings.
It can hurt the Homeowner; Voids Warranty
This type of refrigerant substitution will typically void the manufacturer’s warranty.
It can Hurt the Distributor; Avoiding Complicity
Assisting with this action may place a distributor in a difficult position because it could be interpreted as being
complicit by supporting the operation of a system that is no longer configured with its rated components. Tech
support will not be able to help with issues until the unit is brought back into compliance.
Capacity and displacement mismatch: A2L refrigerants, such as R-454B, have different volumetric cooling
capacities and vapor densities than R-410A. Compressors designed for A2L refrigerants use internal
components and displacement volumes optimized for those properties. Operating the compressor with R-410A
may create an incorrect mass-flow rate, reduce net cooling efficiency, and impair proper heat absorption.
Lubrication concerns: While both system types may use Polyester (POE) oil, operating R-410A under the
mentioned stresses, may overheat the oil and reduce the protective lubricant film on moving metal parts.
Thermal and electrical strain: R-410A may shift operating pressures and alter the motor loading profile.
Internal motor windings and built-in overload protectors, which are sized for the torque and amp draw of the
intended A2L refrigerant, may operate at higher temperatures or experience improper current draw,
accelerating thermal degradation of electrical insulation and related components.
Final Thoughts…
It is imperative that we add the mismatch of equipment to this as well.
It is illegal and voids warranty to match an A2L coil with an A1 condenser or vice versa.
You can change an expansion valve of an A2L to an A1. But whatever refrigerant is first used in the coil brands
it that way for life.
Changing an A1 coil to an A2L coil is illegal as it was not tested as a flammable refrigerant coil.
Also voiding warranty would be to match Brand XXX A2L inside, with Brand YYY A2L outside unless the
match carries an AHRI number.