A valve unit for controlling the delivery of a fuel gas, particularly for water-heating devices

摘要

A valve unit for controlling the delivery of a fuel gas comprises a thermostatic valve (30) with an actuator means (31) which is sensitive to the variation of the water temperature in order to bring about the shutting-off of a main gas-delivery duct (4), a servo-valve (8) having a first closure member (9) with diaphragm control (12), the diaphragm being subjected to the gas-delivery pressure (Pu) on one side and to a pilot pressure (Pt) established in a pilot chamber (13) of the servo-valve on the other side, and a pressure-regulator device associated with the servo-valve (8) and comprising a regulation valve for controlling the pilot pressure (Pt) in the pilot chamber (13).