High capacity circulator line provides temperature control for a cloud and pour point testing, low temperature reactions, sample tempering, viscosity studies and general laboratory cooling applications. A 28-liter reservoir accommodates large or multiple samples. Circulators feature a -25 to 150 C temperature range, an integrated simplex or duplex pump, rapid response heater, and energy-saving refrigeration system. Model 9612 features a Programmable Controller with LCD display, multi-language help menus and time/temperature programming. A digital controller on Model 9602 provides temperature control and stability but without advanced programming, remote probe, or communications capabilities. Model 9606 features a standard controller, offering LED digital display, three user-programmable temperature presets, and a two-speed pump.