OIT Maintenance and Troubleshooting 4

Question 1

A control valve fails to respond to controller output changes. Which fault should be investigated FIRST?

Accepted Answer

Instrument air supply to the actuator

Answer

Loss of instrument air is the most common reason a pneumatic control valve becomes unresponsive.

Question 2

During a routine inspection, an operator finds a small external crack in a pipe elbow. What should be done?

Accepted Answer

Tag and report it to maintenance and engineering for evaluation

Answer

Cracks in pressurized piping are safety hazards that require engineering evaluation before continued operation.

Question 3

What is the function of a steam trap in a process system?

Accepted Answer

Discharge condensate while retaining live steam

Answer

A steam trap automatically removes condensate and non-condensable gases from steam lines without releasing live steam.

Question 4

An operator observes water hammer (banging) in a steam line after opening a valve. What caused this?

Accepted Answer

Condensate pooled in the line before steam was introduced

Answer

Water hammer occurs when high-velocity steam contacts standing condensate, producing a violent pressure surge and noise.

Question 5

A flow transmitter based on differential pressure reads zero even though the pump is running. What is the MOST likely cause?

Accepted Answer

Both impulse lines are blocked or equalizing valve is open

Answer

Blocked impulse lines or an open equalizing valve will equalize pressure across the transmitter, producing a zero reading.

(OIT) Operator in Training Practice Test