Section 431.106 - Uniform test method for the measurement of energy efficiency of commercial water heating equipment(a)Scope. This section contains test procedures for measuring, pursuant to EPCA, the energy efficiency of commercial water heating equipment.(b)Testing and calculations. Determine the energy efficiency of commercial water heating equipment by conducting the applicable test procedure(s): (1)Residential-duty commercial water heaters. Test in accordance with appendix E to subpart B of part 430 of this chapter.(2)Commercial water heating equipment other than residential-duty commercial water heaters. Test in accordance with the appropriate test procedures in appendices to subpart G of this part. (i)Gas-fired and oil-fired storage water heaters and storage-type instantaneous water heaters. Test according to appendix A to subpart G of this part.(ii)Electric storage water heaters and storage-type instantaneous water heaters. Test according to appendix B to subpart G of this part.(iii)Gas-fired and oil-fired instantaneous water heaters and hot water supply boilers (other than storage-type instantaneous water heaters). Test according to appendix C to subpart G of this part.(iv)Electric instantaneous water heaters (other than storage-type instantaneous water heaters). Test according to appendix D to subpart G of this part.(v)Commercial heat pump water heaters. Test according to appendix E to subpart G of this part. 81 FR 79322 , Nov. 10, 2016