Pressure build-up depends on the sealing ring, lid rim, valves, correct assembly and clean seating. If steam escapes too early, the lid cannot reliably reach its intended pressure.

Unusual steam loss can be caused by an aged seal, a dirty valve, a damaged seating surface or an unsuitable spare part.

In a pressure-cooking lid, seal, valves and pressure display work as one system. One unsuitable or aged part can affect the function of the whole lid.