Pumps that are not part of an appliance shall be of a _____-_____ type.

Pumps that are not part of an appliance must be of a positive-displacement type to ensure reliable and efficient operation. Positive-displacement pumps move fluid by trapping a fixed volume and forcing it into the discharge pipe, which is crucial for maintaining consistent flow and pressure. This characteristic is particularly important in mechanical systems where varying flow rates could lead to inefficiencies or operational failures.

Using positive-displacement pumps provides advantages like high efficiency in transferring fluids, the ability to handle varying viscosities, and consistent performance regardless of back pressure. These features make positive-displacement pumps ideal for applications outside of appliances, where control over the fluid process is essential.