An additional valve in hydraulic elevator systems that provides a secondary safeguard against excessive pressure buildup beyond the main relief valve.
Full Definition
The over-pressure valve (also called burst valve or secondary pressure limiting valve) provides a second level of protection against hydraulic over-pressurisation, acting downstream of or in parallel with the main pressure relief valve. It is designed to open at a pressure slightly higher than the primary PRV, providing redundancy. In some code jurisdictions, a separate over-pressure protection device is mandatory in addition to the standard relief valve. The valve may also act as a check valve, preventing backflow. After operation, the valve must be inspected for seat damage and correct re-seating. Testing frequency is defined by the lift maintenance plan and EN 81-2.
