A hydraulic safety valve that limits maximum system pressure to protect the cylinder and hoses from over-pressurisation.
Full Definition
The pressure relief valve (PRV) is a critical safety component in hydraulic elevator systems. It is set to open at a pressure typically 140% of the working pressure, releasing hydraulic fluid back to the tank when system pressure exceeds the safe limit. This protects the hydraulic cylinder, piping, and hoses from rupture under overload conditions or pump runaway. The PRV is installed on the power unit between the pump outlet and the main control valve. Regular testing of the relief pressure is required by EN 81-2 and maintenance standards. An incorrectly set or blocked PRV can lead to catastrophic cylinder failure.
