It was communicated on August 30, 2019 that FER Coil Kits would be needed to facilitate the combination of Trane and Ameristar FER-compliant, condensing furnaces with 4GXC and 4MXC evaporator coils. This remains true for 4MXC or 4GXC coils that have a serial (date) number prior to 19365*.
4MXC and 4GXC coils beginning with serial (date) number 19365* and beyond include a factory-installed heat shield and do not require the use of the MAY*FERCOLKITA accessory. If it is determined based on serial (date) number that a kit is required, please reference the information in the following Product Bulletin about kit model numbers and associated coil sizes.