The Ruelco pneumatic relay is a device used to supply a signal from the outlet when a pilot supply signal is given to the valve. When the pilot supply is removed, the valve will block the inlet and vent the outlet.

Ruelco makes a wide array of stainless steel pneumatically operated relay switches. An Automatic Reset relay is used for continuous operation, while a Manual Reset relay can be used to ensure safety by making it necessary for an operator to put the relay back into service. All Ruelco relays have a high Cv factor which delivers a fast response to a drop in system pressure and are a simple soft seat design, making repair and maintenance easy.