For the water chiller system, How to change the compressor oil? From this article, we will provide you on how to change the compressor oil step by step.

The role of compressor oil

1) Lubrication. It can lubricate the surface parts of the compressor, reduce resistance and friction, reduce power consumption, extend service life.

2) Cooling. It can take away the heat generated in time, Prevent the compressor from overheating and burning off.

3) Sealing. The lubricating oil penetrates into the sealing surface of each friction component to form an oil seal, which can prevent the refrigerant leakage.

4) Reduce compressor noise. Lubricating oil constantly washes friction surface, take away wear debris, can reduce friction parts wear.

Conditions for replacing compressor oil

  1. Water Chillers work for a long time. compressor operation 2000 hours to the first maintenance period, and the cumulative operation of 10000 ~ 12000 hours and then change the oil.

2. Such as motor burn out need to replace the compressor, replacement after continuous operation of 100 hours              need to change the oil

3.  Replace the refrigerating oil after 100 hours of operation of the refrigerating unit used in the tube discharge                  cold  storage.

4. Change the oil according to the cleanliness of the refrigeration system.

Replace the compressor oil operation

1. Close the high-pressure exhaust and low-pressure Suction Stop Valve, use the process valve needle on the compressor to release the refrigerant inside the compressor, so that the compressor crankcase and the atmosphere.

2. Unscrew the drain plug at the bottom of the crankcase, drain the frozen oil from the crankcase and remove the strainer to clean.

3. Nitrogen can be used to blow in from the low pressure charging valve needle, to increase the pressure in the body by hand blocking the oil outlet, to further eliminate the residual oil in the body, to dry the cleaned filter into the body and tighten the oil plug.

Injection method of Compressor Oil

1. Unscrew the process port plunger on the side of the compressor. Use this as a filling port to pour the frozen oil into the crankcase through a suitable tool.

2. (For the Piston Machine) The fluorine-filled meter low-pressure pipe is connected to the low-pressure process valve needle of the compressor cavity, use the vacuum pump to draw the crankcase to negative pressure, and separate the other fluorine-filled pipe, insert one end into the container containing the frozen oil The other end is connected to the valve needle of the low-pressure suction end of the oil pump, and uses the negative pressure in the crankcase to suck the frozen oil into the crankcase.

3. The original system may have a certain amount of residual oil, it can be added some less, generally added to the lower limit of the standard oil mirror can be the slightly higher position.

4. After filling the frozen oil, tighten the process plunger or remove the fluorine-filled pipe, and connect the fluorine pressure gauge to vacuum the compressor

5. Open the high and low pressure cut off valve of the compressor after vacuuming to check if there is any refrigerant leakage

6. If there are no leaks wait 20 minutes to start the water chiller unit.

7. Once start up the water chiller should immediately check the compressor lubrication and oil level of oil mirror, if the oil level is below the normal range (1 / 4 of the Mirror). must add frozen oil. If necessary, the oil pressure can be checked by connecting the oil pressure gauge to the needle valve of the oil pump. The suction side pressure of the oil pump should be basically consistent with the suction pressure of the low pressure. The allowable value of the oil pressure difference is 1.4 ~ 3.5 bar. The screw water chiller is a pressure difference type oil return, no oil pump.

Notes for refueling

1. the frozen oil has a certain hygroscopicity, water in the oil and oil chemical reaction, and can not be removed by vacuum, work requires special care to minimize air into the system and oil storage containers.

2. the replacement of the compressor should be noted that the original water cooling system has a certain amount of frozen oil, the system should be necessary to blow out the remaining oil, if there is a large amount of oil in the system, restarting there is the risk of fluid percussion.

3. Don’t change the oil on a rainy day.