Question 152Steam Plants - 1st Asst/Chief

The correct answer is C) set screw. On a boiler safety valve, the blow down adjusting ring is locked in place by a set screw. This set screw is used to secure the adjusting ring and prevent unintended changes to the safety valve's blow down setting. The set screw provides a secure, positive locking mechanism to maintain the proper adjustment of the safety valve. The other answer choices are incorrect because: A) a wire seal would not provide a secure, mechanical locking mechanism; B) a locknut is not typically used for this purpose; and D) a cotter pin is not the appropriate fastener for locking the adjusting ring in place.