compressor oil charging?

[THERMOACC]

Hi all,
Would anyone inform me of the correct way to top up the oil in screw compressors? I`ve talked to a few people on this subject and the procedure differs slightly depending who I talk to! Any help on this matter would be great!:)

[Andy]

Hi all,
Would anyone inform me of the correct way to top up the oil in screw compressors? I`ve talked to a few people on this subject and the procedure differs slightly depending who I talk to! Any help on this matter would be great!:)

Hi Thermoacc:)

different compressors different methods.

I have two methods.

1/ shut off compressor from system remove the refrigerant, vac compressor out and suck ther new oil into the oil tank.

2/ connect an electric oil pump to a charging point on the oil tank, open the valve and pump the oil in.

Hope this helps.

Kind Regards Andy:)

[NoNickName]

Get a used small 5 liters liquid receiver. Connect two capillary pipes with in-line shutoff valves to inlet and outlet. Install a cap to the dafety valve threaded connection.
Pour oil through the said connection, top it up and close the cap, then vacuum the liquid receiver.
Connect the inlet capillary to the high pressure of compressor, and the outlet capillary to the low pressure.
Open the high side valve completely, and slowly open the low side valve until you hear the oil going through.
Close the valves when happy.
Disconnect the capillary, beware of the oil spray.

[Superheat6k]

The oil in most screws is highly viscous (thick). The method for getting it in will vary from make to make.

For instance in an Hitachi the easiest method is to remove the large pressure relief Vv on the discharge housing and simply pour it in (please pump out the gas first). Avoid keeping the oil exposed to air for too long as it is very hygroscopic (absorbs moisture). The compressor should be thoroughly evacuated afterwards.

Another method is to put the oil is a small liquid receiver and purge it in using OFN at a higher pressure than the system standing pressure, but if you use this method the receiver should be pressure tested appropriately above the purge pressure and use of a sightglass in the line is vital to prevent ANY nitrogen entering the compressor. If this does happen the compressor will require to be vacced out.

Warming the oil to reduce the viscosity also helps greatly.

[nh3wizard]

Hi all,
Would anyone inform me of the correct way to top up the oil in screw compressors? I`ve talked to a few people on this subject and the procedure differs slightly depending who I talk to! Any help on this matter would be great!:)

For Nh3, I usually pump down the compressor, and add it straight into the oil separator with an electric pump.:D