Adding Oil

[gwilliamson]

IS THERE A GUIDE TO THE AMMOUNT OF OIL NEEDED FOR VARIOUS SPLIT UNITS WHEN RE GASING AFTER A LEAK? (ITS A 7KW 410A NON INVERTER lg)
If & when i vac the system will the old oil remain in the unit?

[puddleboy3]

Im interested to hear what everyone else has to say about this as i have never added any oil to a split system after it has lost its refrigerant charge! i know that the new Daikin G type scroll compressor will keep 99% of its oil in the compressor! How they do it i dont know but thats what they claim. If this is the case then after leakage there would be no need to add any oil. The problem with your system will be knowing how much oil is still in the system without draining the compressor!

[afeef]

hi dear
on the name plate of the compressor mentioned the amount of oil required , the oil must be changed every 10000 hr. of running, that is about 4-5 years.
if your compressor have reach (or almost)this period, it is better to change the oil,
if the oil in system have long term in contact with air(the leak is not repaired for long time),it is better to change oil, because the oil is contaminated and oxidized by atmospheric air ,
all regards

[old gas bottle]

tricky one,some compressors have sight glasses so you can just pump some in,[half way up the glass] if not its try to guess how much its lost and add some,bear in mind it allways looks worse than it is,otherwise as previously stated its remove the compressor,drain it and add the correct charge , your choice!!

[gwilliamson]

So, Would That Mean If Its A Recent Leak There Would Probably Be Oil Left In The Compressor And If So Will Vacuuming The System Remove The Oil?

[herefishy]

Evacuating the system will not remove the oil.

If for some reason you suck oil out of piping that you are evacuating (I have seen this) - you will know because your vacuum pump will begin to fill (if you observe the pump oil level SG).

The oil will not evaporate during an evacuation - as oil does not readily evaporate or disappear in the event of system leakage. Any loss of oil will be observable in the area of the leak.

Did you observe a big puddle of oil at the location of leak? If not - you have nothing to be concerned about.

condensing units are usually charged with somewhat of a reserve, in order to compensate for a maximum anticipated or specified line set length. Unless you have an unusually long line set and observed a lake of oil in the equipment - again you have no worries.

The oil charge is not "critical" (in terms of exact amount), and again manufacturers usually charge the equipment at the plant (with oil) for worst case scenario.

If this equipment appears to have experienced compressor replacement previously - likely there is an excess of (the minimum required amount of) oil in the system (which likely has no poor effects on the system).

In my 26 years of experience, I cannot recall a situation in which a refrigerant leak caused an oil related failure. Usually oil related failures are symptomatic of other system failures which result in low refrigerant velocities and creating a poor oil return situation back to the compressor - or mechanical failure within the compressor itself (bad valves, excess blow-by, overpressurized crankcase, etc.)

In fact, I have on occassion suffered failure from "Too Much" oil in a system. This resulting from a compressor failure in which the faulty compressor pumped it's entire oil charge into the system - and the oil didn't return. This resulted in the subsequent replacement compressor (hermetic) filling up with oil and getting stuck (as opposed to lock rotor - becuase locked rotor amps were not observed). I removed the compressor - dumped a double charge of oil out - recharged - put it back in the system and it ran for years.

Subsequently after a year or two, that compressor failed. On the second go-round, I put the numbers to the system and determined that the suction line was oversized - I don't know who installed it originally.

anyway, there-ya-go.


Cheers!

[Bahaaeldeen]

thanks a lot herfishy , ur information is really wonderful
Best wishes
Bahaaeldeen

[S_Line]

if there has been a leak and you can see a pool of oil i would add some, but only by the look of the amount that has been leaked out