In order to meet the new federal Fan Energy Rating (FER) standards, we have reengineered our furnaces by using a combination of several technology and feature changes. As a result of some of these design changes, certain S-Series and Ameristar furnaces have higher operating temperatures than before.
When installing a 4GXC or 4MXC coil on the new S-Series or Ameristar condensing furnaces, you must use an FER coil kit, MAY*FERCOLKITA, to protect the quality and integrity of the coil’s drain pan. The MAY*FERCOLKITA kits come with a metal heat shield and are available in each coil cabinet size.
For a list of impacted furnace families and kit numbers, please see the charts in the document linked below.