Which statement correctly describes the interval and marking requirement for element changes?

• A. Record the change date in the log
• B. Date the unit on the outside
• C. Keep the unit untouched for 5 years
• D. The month and year should be stenciled on there

Answer: (D)

Marking the date on the item itself is essential for maintenance control. The month and year stenciled on the element provides a visible, durable record of when the change occurred, so anyone handling or inspecting the part can quickly verify if it’s within its service interval. Written logs are important for documentation, but an on-item mark ensures the date isn’t missed during quick checks. Other options fall short: recording in a separate log doesn’t provide an at-a-glance indicator; dating the unit on the outside is vague and easy to misread; and leaving the unit untouched for years ignores needed maintenance. Therefore, stenciling the month and year on the element is the proper marking method.