For pump types with impellers that may be trimmed between catalog trims, is_numeric will be true. In this case, numeric_impellers will be populated with all of the available trims for the pump, including both catalog trims and incrementel trims. The associated unit will be passed as a string in the numeric_unit field. Numeric impellers may be sent to [!:change_pump_diameter] or as a member of the change_diameter parameter sent to [!:change_pump].

Some pumps have impellers that may be adjusted at increments between the listed catalog curves. In those instances, this list should contain both the catalog trims, and the available trims that lie inbetween them. Because these are numbers, units are not included as part of the field value The appropriate unit label can be found in the numeric_unit property. If this list is empty, check string_impellers instead.

If returned curve labels contain trimmable numeric data, the associated unit label will be reported here.

Some Pumps have named impellers that do not reflect numeric trim increments. For these pumps, it is safe to switch between named impellers, but it is not possible trim between them. As a convenience, trimmable pumps may also report trims here. In this case they are just the catalog trims, not the incremental trims in between, and include unit labels in the string.