46 C.F.R. § 153.430
Heat transfer systems; general
Each cargo cooling system required by this part and each cargo heating system must:
(a) Meet the standards of Subchapters F (Marine Engineering) and J (Electrical Engineering) of this chapter;
(b) Have valving that enables the system to be separated from all other cooling and heating systems; and
(c) Allow manual regulation of the system's heat transfer rate.