Why might an inverted bucket trap release live steam?

An inverted bucket trap can release live steam if it has lost its prime. This occurs when the mechanism that allows the trap to function effectively has been compromised, leading to the bucket becoming unable to maintain the necessary balance between condensate and steam.

In a properly functioning inverted bucket trap, the bucket floats in the condensate, allowing it to trap steam and release condensate while preventing the escape of steam. If the trap loses its prime—meaning it no longer has the necessary water to create that balance—it will not close properly. Consequently, live steam may escape due to the inability of the trap to seal effectively against the steam pressure, which is the fundamental reason why loss of prime can lead to the release of live steam.

Other potential issues, such as overfilling with condensate, operating under high pressure, or having a corroded body, could cause problems with a steam trap's performance but are not directly responsible for the release of live steam in the same way that losing prime does.