All fire tube boilers equipped with a gas burner will have a valve proving system (VPS) to verify the integrity of the gas solenoid valves on the burners for any online leakage and provide a safety trip mechanism. In simple terms, a valve proving system is a safety control used on gas fuel-fired equipment that ensures the effective closure of two safety shutoff solenoid valves in series by detecting gas leakage. What is a Valve Proving System? Gas valve train with double sol