The Mark 79 is an air-operated control valve that can accept a 3-15 psi air sginal from any of the temperature or process controllers sold by Jordan Valve. It can also be controlled by instruments such as turbidity, flow or level controllers and can be set up for direct control or with optional side or top mounted positioners.

The Mark 79 is used for diverting service and is ideal for bypassing fluids around coolers or filters. The Mark 79MX is used as a combining or mixing valve with two inlets and one outlet.