5 Symptoms of AC Compressor Failure

Pour the oil very slowly into the intake port or low side of the compressor. This is where the large line entered. While pouring in the refrigerant oil, rotate the hub and clutch slowly to let the oil enter the compressor.

How to Know When an Air Compressor Needs Oil

1. Determine the date on which the air compressor’s oil was last changed.
2. Locate the sight glass or dipstick that measures the amount of oil in the air compressor.
3. Observe the amount of oil in the air compressor through the sight glass or by lifting out its dipstick.

1. The compressor doesn’t turn on at all.
2. The system is blowing warm air.
3. The system keeps tripping the circuit breaker.
4. The outside unit shakes when it starts up.
5. The outside condensing unit is making strange noises.

To test if the compressor is pumping properly, the compressor current draw must be compared to published compressor performance curves using the operating pressures and voltage of the system. If the average measured current deviates more than ±15% from published values, a faulty compressor may be indicated.

about 12-15 years

After floodback and slugging, Park said the major causes of compressor failure, in order of importance, include bad contactors, system leaks, dirty evaporators, dirty filters, dirty condensers, rapid loading/unloading, mis-wired/misadjusted controls, low superheat, and wrong oil for the system refrigerant.

One of the symptoms of an inefficient compressor is high suction pressures along with low discharge (head) pressures. If the compressor is inefficient, the evaporator cannot handle the high heat load due to a decreased refrigerant flow rate, and the conditioned space temperature will start to rise.

Low refrigerant also damages the compressor, the “heart” of the air conditioner where the liquid refrigerant is squeezed into a high pressure gas. The compressor is designed to match the refrigerant charge, and if it drops, the compressor will start to overwork and will soon break.

Different compressors use different lubrication techniques. In screw compressors, the oil is often pumped into the moving parts, while pistons and scrolls often employ splash lubrication using oil from a vessel in the bottom of the compressor.

Centrifugal compressors are inherently oil free as no oil enters the compression chamber. Lubricated parts are separated from the compression chamber by air seals and oil seals, separated by an atmospheric vent area.

There are two main types of compressor oil: standard oil (also called mineral oil) and synthetic oil. Standard (Mineral) Compressor Oil. Standard compressor oil is made by using a mineral base and are cheaper than synthetic compressor oil. Mineral oil is more volatile and is more likely to evaporate than synthetic oil.

The Clear Choice for Lubricated Compressors In general, manufacturers today recommend using either a 20 or 30 weight synthetic lubricant — rather than a mineral oil — to get the best results out of your industrial compressed air system.

Most manufacturers recommend SAE20 or SAE 30 for compressor oil. Similar to the way motor oil works, if your area is colder, a SAE20 oil would be better suited. On the other hand, SAE30 oil is more viscous, which means it will coat better and provide more protection in warmer temperatures.