A relay valve (2) includes a housing having a pressure medium inlet that can be connected to a pressure medium source, at least one pressure medium outlet that can be connected to a consumer, at least one control input, and at least one ventilation (32) leading to the atmosphere. The relay valve (2) has further a relay valve piston (14), which is arranged in the housing along a relay valve piston axis (16) in a slidable manner. The relay valve (2) has a first sealing element (54) fixed to the housing, and a second sealing element (56) fixed to the relay valve piston for sealing the relay valve piston (14) with respect to the housing. An annular space (58) having a connection to the atmosphere is defined by the first sealing element (54), the second sealing element (56), the relay valve piston (14), and the housing.

A method of decreasing tire pressure includes opening a wheel valve (22) to allow pressurized air from a tire (10) to be directed to a first valve assembly (14) and to atmosphere. A target pressure is selected for a fluid control conduit (28). The fluid conduit (28) is in fluid communication with the first valve assembly (14) and a second or control valve assembly (30). The pressure in the fluid conduit (28) is measured. If the measured pressure is greater than the target pressure, then the second valve assembly (30) is de-energized. If the measured pressure is less than the target pressure, then the second valve assembly (30) is energized. A valve (42) prone to leak under very low temperatures may be subjected to repeated cycles of pressure application and pressure release in order to form a fluid-tight seal.

An array of valves are arranged in n columns and m lines and which are each designed to control a fluid flow in an associated flow channel in a lab-on-a-chip system. The array includes at least two valves, every column having not more than one valve and every line having from zero to n valves. A device is used for actuating the valves. The valves are pressure-actuated. To produce the device, the flow channels are arranged in accordance with the arrangement of the valves. Which valves are actuated being changeable by movement of projections relative to array of valves so as to change which valves the projections are pressed against.