CARO Preventive Maintenance 2

Question 1

What is the most reliable reference for the correct running oil level in a reciprocating compressor sight glass?

Accepted Answer

The compressor manufacturer's specifications

Answer

Correct oil level varies by machine design, so the manufacturer's specification is the authoritative reference.

Question 2

A V-belt drive is being checked during routine maintenance. What is the common rule of thumb for proper belt deflection?

Accepted Answer

1/64 inch per inch of span

Answer

A deflection of about 1/64 inch per inch of span is the widely used guideline for V-belt tension.

Question 3

An operator feels a noticeable temperature drop across a liquid line filter-drier. What does this most likely indicate?

Accepted Answer

The drier is restricted and causing a pressure drop

Answer

A temperature drop across a drier indicates a pressure drop and flashing caused by a restriction.

Question 4

In a halocarbon system, a moisture-indicating sight glass shows yellow instead of green. What should the operator conclude?

Accepted Answer

Moisture is present and the drier may need changing

Answer

On most indicators, yellow (or pink) means wet while green (or blue) means dry.

Question 5

Why is vibration data on compressors and pumps trended over time rather than checked only once?

Accepted Answer

To detect gradual changes that signal developing bearing, alignment, or balance problems

Answer

Trending reveals changes from a baseline, allowing repairs before a failure occurs.

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