Abstract: A pneumatic relay and instrument housing combination. The instrument housing has walls that define an interior cavity with an access opening closed by a closure. The instrument housing has a gas inlet aperture and a gas outlet aperture both of which extend through the walls to allow fluid communication from exterior into the interior cavity. The pneumatic relay is disposed within the interior cavity of the instrument housing and has an upper body portion and a lower body portion, which together define an interior chamber in which is disposed a pneumatic valve. All flow channels necessary to connect the pneumatic relay to the gas inlet aperture and the gas outlet aperture of the instrument housing are integrally formed into the upper body portion of the pneumatic relay.