(a) DOE may, at any time, test a basic model to assess whether the basic model is in compliance with the applicable energy conservation standard(s).

(b) For variable refrigerant flow multi-split air conditioners and heat pumps (other than air-cooled with rated cooling capacity less than 65,000 btu/h), when DOE may require that the manufacturer of a basic model ship at its expense any means of control for the basic model necessary for conducting testing in accordance with Appendix D1 to subpart F of 10 CFR part 431 of this subchapter.