Which component provides the relief mechanism in a PV vent?

• A. A spring
• B. A diaphragm
• C. A lever
• D. A gasket

Answer: (A)

Relief in a PV vent is provided by a spring-loaded valve. Under normal conditions, the internal pressure is held in check by the spring’s opposing force, keeping the valve closed. When the internal pressure rises to the setpoint, the pressure overcomes the spring force and pushes the valve open, allowing venting to prevent overpressure. The spring’s setting determines when the vent begins to relieve and helps re-seal once pressure drops. Diaphragms or gaskets may form part of the sealing surface, but the actual mechanism that opens to relieve pressure is the spring-backed valve action.