Referring to the illustrated bellows-type thermostatic steam trap, what statement is true concerning its operation? GS-0005

Correct Answer: Option A — When the bellows comes into contact with relatively cool condensate, the vapor within the bellows condenses resulting in bellows contraction and valve opening.

Bellows-type thermostatic traps utilize a volatile liquid inside the bellows. When cool condensate contacts the bellows, the internal vapor pressure drops, causing the bellows to contract and open the valve. This allows condensate discharge, adhering to standard thermodynamic principles for steam system drainage as outlined in marine auxiliary machinery maintenance.