The most common type of compressors used in industrial settings are the rotary screw air compressors. There are many weird ideas surrounding these rotary screw compressors. Most of those ideas have to do with cold weather and winterization. Simple maintenance can solve many of the problems and failures that go along with winter weather.



Many people think that because their compressor is inside a heated building, it will not be affected by outside air temperatures. This is not true, because the oil coolers are often vented to the outside of the building. Oil that is trapped in a cooler that is exposed to cold air can become thick and will not circulate. Some rotary screw air compressors have thermal or bypass valves in the oil cooling system. This helps protect the compressor parts during startup in cold weather.

The valve must be checked regularly to ensure that it is operating properly. Synthetic oil can be a good help because it will circulate easier at low temperatures. However, the real problem is water build up in the oil sump because the water will not boil off and evaporate when the compressor is working under 140 degrees F. Problems caused by the water buildup can be avoided by occasionally draining a small amount of oil during cold weather before starting the compressor up.

Cold weather sometimes causes condensation to buildup in the air lines of the rotary screw air compressors. This can cause sensors to send the wrong signals to the screw compressors computer control systems. This will cause the compressor to run with a full load until someone notices the constant lifting of the pressure relief valves. Condensation is removed through drains that are placed strategically in the air system.

These discharge lines are usually taken to a drain point outside of the building. During cold weather, these lines can become clogged with ice, forcing condensation back into the air system. If not properly drained before the compressor is shut down, this can damage some of the compressor parts and expensive components.

It is common for businesses to take their rotary screw air compressors out of service during the winter months. This is good only if the proper steps are taken to winterize the screw compressors. This includes oil and filter changes.

Used oil generates an acid that can damage the bearings in the motor and the compressor parts. Manually rotating the motors and keeping the rotors oiled are also important to avoid seizing at startup. Proper maintenance of the screw compressors is important to avoid expensive service calls and to minimize downtime.