What is the secondary function of a steam trap?

• A. To remove any air condensable gases from steam system
• B. To increase steam velocity
• C. To mix condensate with make-up water
• D. To vent steam to atmosphere

Answer: (A)

The secondary function of a steam trap is to purge air and other non-condensable gases from the steam system. Air in the lines acts like an insulating layer, reducing heat transfer and can lead to poor condensate drainage, corrosion, and equipment issues if it accumulates. By venting these gases, the trap helps maintain efficient heat transfer and reliable condensate removal. The other ideas—increasing steam velocity, mixing condensate with make-up water, or venting steam to atmosphere—do not describe what a steam trap is intended to do beyond discharging condensate.