You will need a Refrigerated/Heated Circulator if your working temperature will ever be near or below ambient. Applications that require maximum temperatures above 160°C or ±0.01°C temperature stability require Circulators with Performance or Advanced Series Temperature Controllers.

A Circulator with a small reservoir is generally suitable if you require external circulation only and the heating/cooling demand is moderate. If the external heating/cooling demand is high or you will be putting samples in the internal reservoir, a Circulator with a larger reservoir will be required.

All PolyScience Temperature Controllers can be used for close-loop external circulation. If open-loop external circulation is required, or if your application requires a flow rate above 3 gpm (11 l/min), a Circulator with a Performance or Advanced Series Controller is required.