The RLZ serie pressure regulator, has an adjustable setpoint spring. The pressure regulator complies with EN 88-2. Fuel/combustion air ratio regulation, Revamping of combustion systems from modulated fixed air/gas to Stoichiometric ratio - High flowrate coefficient, - High accuracy, evenat maximum flow rates, - Inlet pressure compensation diaphragms - Reduced response times, - No internal leakage at zero flow rate, - Periodical maintenance without disassembling the body from the pipework.