Why is an inspection important for reciprocating compressors?

There are many types of annual inspection.

Some maintenance staff only carry out the instructions of the compressor block manufacturer. We need to realise that the compressor block is just one part of a whole compressor unit. The manual instructions are only a guideline. Important user information fulfills the balanced maintenance plan. Effects like the start-stop cylus-part load or VSD drive can make a big difference in maintenance. It may not sound logical, but a compressor in 24-hour operation needs less maintenance than an installation that operates only 2000 hours a year with twice the number of stops and starts.

That is one of the reasons why VSD driven compressors need less maintenance. The key to this is the temperature of the lubrication oil. When a compressor experiences more stops and starts, the oil needs to be heated during each start-up. During this warming process, the oil experiences changes as the temperature changes.


Sometimes during the recommended inspection, the focus is solely on the valve plates. In fact, the big end bearings can provide us with more information about the compressor. We recommend always checking the big end bearings of your compressor.

How can the big end bearings, which operate under the same conditions on the same crankshaft, show different wear?

The answer: imbalance in your compressor unit. This is easy to repair if you find the indications in due time; if not, you will experience unexpected damage.

We recommend including this small check in your inspections.

Other important facts that demonstrate an imbalance in your reciprocating compressor:

  • Increased oil consumption.
  • Increased drainage of the shaft seal or more defects.
  • Increased e-motor bearing replacement  in direct driven compressors (more than once in 5 years)
  • Increased wear on V-belts in V-belt driven compressor units

If you suspect that your compressor is experiencing the symptoms of imbalance, feel free to contact us. RM Support has extensive experience in restoring balance to compressors.