(a) When testing of covered products or covered equipment is required to comply with section 323(c) of the Act, or to comply with rules prescribed under sections 324, 325, or 342, 344, 345 or 346 of the Act, a sample comprised of production units (or units representative of production units) of the basic model being tested shall be selected at random and tested, and shall meet the criteria found in Sec. Sec. 429.14 through 429.54 of this subpart. Components of similar design may be substituted without additional testing if the substitution does not affect energy or water consumption. Any represented values of measures of energy efficiency, water efficiency, energy consumption, or water consumption for all individual models represented by a given basic model must be the same.
(b) Unless otherwise specified, the minimum number of units tested shall be no less than two (except where a different minimum limit is specified in Sec. Sec. 429.14 through 429.54 of this subpart); and