{"id":48877,"date":"2026-03-13T15:37:51","date_gmt":"2026-03-13T19:37:51","guid":{"rendered":"https:\/\/cetechsupport.com\/?page_id=48877"},"modified":"2026-03-16T09:15:47","modified_gmt":"2026-03-16T13:15:47","slug":"a2l-refrigerants","status":"publish","type":"page","link":"https:\/\/cetechsupport.com\/es\/a2l-refrigerants\/","title":{"rendered":"Guidance on A2L Refrigerant Systems and Retrofits in Legacy Air Handlers"},"content":{"rendered":"

Guidance on A2L Refrigerant Systems and Retrofits in Legacy Air Handlers<\/h2>\n\n\n\n

As the industry transitions to lower-GWP refrigerants under the AIM Act technology transition<\/strong>, many new residential and light commercial systems will utilize A2L refrigerants (such as R-454B\/R-32)<\/strong>. These refrigerants introduce additional safety requirements that directly impact how HVAC equipment must be designed and installed.<\/p>\n\n\n\n

We have recently seen questions from contractors about installing third-party evaporator coils, metering devices, and aftermarket A2L leak detection sensors into older air handlers<\/strong> that were originally designed for A1 refrigerants (such as R-410A).<\/p>\n\n\n\n

It is important that our teams understand and communicate the following:<\/p>\n\n\n\n

1. A2L Systems Must Be Designed and Certified as a Complete Appliance<\/h3>\n\n\n\n

Equipment using A2L refrigerants must comply with UL 60335-2-40<\/strong>, the safety standard governing HVAC appliances containing flammable refrigerants.<\/p>\n\n\n\n

Under this standard:<\/p>\n\n\n\n

    \n
  • A Refrigerant Detection System (RDS)<\/strong> is required for many indoor units.<\/li>\n\n\n\n
  • The sensor location and mitigation controls are part of the appliance safety design<\/strong>.<\/li>\n\n\n\n
  • The sensor placement is determined during manufacturer testing and certification<\/strong>.<\/li>\n<\/ul>\n\n\n\n

    Because of this, the sensor location must be defined by the manufacturer and installed according to the manufacturer\u2019s instructions<\/strong>.<\/p>\n\n\n\n

    2. Equipment Must Be Installed According to Its Listing<\/h3>\n\n\n\n

    The International Mechanical Code (IMC)<\/strong> requires mechanical equipment to be installed in accordance with the manufacturer\u2019s installation instructions and the conditions of the product listing<\/strong>.<\/p>\n\n\n\n

    This means:<\/p>\n\n\n\n

      \n
    • HVAC equipment must be installed as tested and certified by the manufacturer<\/strong>.<\/li>\n\n\n\n
    • Modifying equipment outside of that tested configuration creates an unlisted appliance<\/strong>.<\/li>\n<\/ul>\n\n\n\n

      3. Field-Engineering an A2L Appliance Is Not Permitted<\/h3>\n\n\n\n

      Installing a combination such as:<\/p>\n\n\n\n

        \n
      • a third-party evaporator coil<\/strong><\/li>\n\n\n\n
      • a new metering device<\/strong><\/li>\n\n\n\n
      • a third-party A2L leak sensor<\/strong><\/li>\n\n\n\n
      • inside an older air handler cabinet<\/strong><\/li>\n<\/ul>\n\n\n\n

        creates a configuration that has not been tested or listed under UL 60335-2-40<\/strong>.<\/p>\n\n\n\n

        Because the air handler was not originally designed and certified for A2L refrigerants, adding aftermarket components does not make the equipment compliant<\/strong>.<\/p>\n\n\n\n

        4. Why Manufacturers Specify Sensor Locations<\/h3>\n\n\n\n

        A2L sensors are typically installed near the evaporator coil and lower areas of the cabinet<\/strong>, where refrigerant is most likely to accumulate during a leak.<\/p>\n\n\n\n

        These locations are determined through leak dispersion and safety testing during product certification<\/strong>. As a result, manufacturers must specify the sensor mounting location as part of the equipment design.<\/p>\n\n\n\n

        5. Sales Guidance<\/h3>\n\n\n\n

        When asking about converting or retrofitting older air handlers for A2L refrigerants, the correct guidance is:<\/p>\n\n\n\n

          \n
        • A2L systems must be installed in equipment designed and listed for that refrigerant<\/strong>.<\/li>\n\n\n\n
        • Legacy air handlers cannot be converted into compliant A2L appliances through aftermarket components<\/strong>.<\/li>\n\n\n\n
        • The proper solution is to install equipment designed and certified for A2L refrigerants<\/strong>.<\/li>\n<\/ul>\n\n\n\n
          \n\n\n\n

          Key Takeaway<\/h3>\n\n\n\n

          A2L refrigerant systems are not simply a refrigerant change<\/strong>. They involve specific safety controls, detection systems, and certified equipment configurations. Installing aftermarket components into legacy air handlers does not meet the UL safety standard or mechanical code requirements<\/strong>.<\/p>\n\n\n\n

          If there are questions about specific installations or equipment compatibility, please reach out to the Technical Support team<\/strong>.<\/p>","protected":false},"excerpt":{"rendered":"

          Guidance on A2L Refrigerant Systems and Retrofits in Legacy Air Handlers As the industry transitions to lower-GWP refrigerants under the AIM Act technology transition, many new residential and light commercial systems will utilize A2L refrigerants (such as R-454B\/R-32). These refrigerants introduce additional safety requirements that directly impact how HVAC equipment must be designed and installed. […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_coblocks_attr":"","_coblocks_dimensions":"","_coblocks_responsive_height":"","_coblocks_accordion_ie_support":"","_uag_custom_page_level_css":"","site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"disabled","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"set","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"class_list":["post-48877","page","type-page","status-publish","hentry"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"trp-custom-language-flag":false},"uagb_author_info":{"display_name":"Carrier Enterprise","author_link":"https:\/\/cetechsupport.com\/es\/author\/joshg\/"},"uagb_comment_info":0,"uagb_excerpt":"Guidance on A2L Refrigerant Systems and Retrofits in Legacy Air Handlers As the industry transitions to lower-GWP refrigerants under the AIM Act technology transition, many new residential and light commercial systems will utilize A2L refrigerants (such as R-454B\/R-32). These refrigerants introduce additional safety requirements that directly impact how HVAC equipment must be designed and installed.…","_links":{"self":[{"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/pages\/48877","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/comments?post=48877"}],"version-history":[{"count":4,"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/pages\/48877\/revisions"}],"predecessor-version":[{"id":48956,"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/pages\/48877\/revisions\/48956"}],"wp:attachment":[{"href":"https:\/\/cetechsupport.com\/es\/wp-json\/wp\/v2\/media?parent=48877"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}