A used Rotary Screw

[Rick Fisher]

Found a used 5hp Rotary Screw compressor .. Its a 2007. I have a big 80 gallon 5hp unit right now, air capacity is fine, but its so loud, I hate it .. I have a small shop and when the compressor kicks in.. it makes me jump ..

Anyway .. I know nothing about Rotary screw compressors .. The idea of super quiet is what interests me .. Wondering from someone who owns one, how many hours is too many hours ? Are they okay to sit turned off for days at a time ? I ask because my understanding is that they need to stay oily inside. I know that when they get old they get rebuilt, and its expensive .. Oil changes are supposed to be expensive.. are they done based on age or hours used ?

I honestly don't think I would run it 100 hours a year.. So I would expect that it would last me 20 years or more..

[J.R. Rutter]

I have been using a rotary compressor for close to 10 years. I got it new from Eaton (now Polar) - Chinese cabinet and controller, German pump, American motor. I installed it above my office and unless it is dead quiet in the shop, I can't hear it cycle. Maintenance is oil and air+oil filter change every XXXX hours, with an oil separator change at about 2x to 3x that interval. The controller tracks hours and puts up a maintenance code as the interval approaches. The oil circulation starts before actual pump load is applied, so it basically takes care of lubrication automatically after extended shut down. I got a refrigerated air dryer from them as well, and do not get any moisture in my tank, just some oil mist blow-by. I probably have over 5000 hours on mine and have done about 3 oil changes and one separator change. Only issue so far has been a pressure sensor, which was an easy fix once diagnosed.