Most coolers today operate close to maximum capacity if the compressor is operating at full load. If the ambient temperature around the compressor increases and does not provide additional air flow to remove the excess heat, you will run into a situation where the compressor runs hotter. Most manufacturers design their coolers for 100 percent capacity at an ambient temperature of 100°F (38°C) and 70 percent relative humidity. If conditions around your compressor are more severe than this, special precautions may be necessary.

For a rotary compressor, a temperature of 212°F (100°C) is not excessively high. Most compressors have a cutoff at 225 to 235°F (107 to 113°C). Keep in mind that at temperatures above 190°F (88°C), fully synthetic oil is necessary. Have a sample of the oil analyzed every 500 hours to verify the oil condition. Also, inspect and clean the coolers regularly. (Tom Muckian, manager of technical services, The Whitmore Manufacturing Co.)

We send $100 for each tip published. Submit your tip.

The following 10 tips are provided to allow anyone new to the oil analysis game to come to terms with his or her reports.

Tip No. 1: Know the sampling point before reviewing its report.

Tip No. 2: Provide feedback to the lab regarding your findings.

Tip No. 3: Learn about magnitudes of change for common test results.

Tip No. 4: Locate the worst reports and address them first.

Tip No. 5: Prove the report's clerical data before examining the numerical data.

Tip No. 6: Read and interpret the report in a logical order.

Tip No. 7: Look for confirming diagnostics/symptoms.

Tip No. 8: Gauge your response; don't under- or overreact.

Tip No. 9: Get into a report-reading routine.

Tip No. 10: Read your reports today.

These tips originally appeared in the following article: Mark K. Smith."Interpreting an Oil Analysis Report - The Top 10 Tips." Practicing Oil Analysis magazine, May 2003.

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Q. I have a question regarding why a lab might instruct a person to check the shaft alignment for possible imbalance. I also use vibration analysis as a tool and I ask myself how one may use oil analysis as an indicator for out-of-tolerance vibration levels such as imbalance. What oil analysis test result would indicate this?

- Dave Tiffany, maintenance specialist, City of Ft. Collins, Colo.

A. Actually, the only way you will detect imbalance with oil analysis is when the component starts wearing, and obviously one does not want to be in that situation. Imbalance is a phenomenon in which vibration analysis is the leading indicator, and oil analysis is the lagging one. Based on my oil analysis background, and because I've seen many samples with acceptable lube condition, acceptable contamination levels and obvious wear - checking for imbalance is a task I regularly suggest in the situation you described, particularly on high-speed equipment. It is not possible to directly check for imbalance using oil analysis. Perhaps a recommendation should be worded like "check for shaft imbalance/misalignment with vibration analysis." This is an excellent example of why one should use complimentary technologies to ensure your reliability goals are met.

- Ashley Mayer, technical consultant, Noria Corporation

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