Hermetic compressor oil charge

[Refrig1234]

Wondering if anyone out there has a method of determining an oil level in a hermetic compressor?
Maybe somehow using temperature difference on the shell during runtime as a rough estimate?
Or perhaps silver brazing a port near the oem oil level to check while the systems pumped down?

I could see something like this being useful after an emergency changeout on a system that might have had multiple compressor failures and a possibility of to much oil in circulation.

[pecmsg]

Wondering if anyone out there has a method of determining an oil level in a hermetic compressor?
Maybe somehow using temperature difference on the shell during runtime as a rough estimate?
Or perhaps silver brazing a port near the oem oil level to check while the systems pumped down?

I could see something like this being useful after an emergency changeout on a system that might have had multiple compressor failures and a possibility of to much oil in circulation.

Let it flood and look at the sweat ring.

Never worried about oil level.

[stumpdigger]

Oil level in a hermetic small ton compressor should not matter much as long as it is piped correctly. If we were to debate anything about a hermetic system would be the ability to change the oil should the system become acidic. The best way to get acid out of a system is to change the oil.

[Refrig1234]

Copeland puts sightglasses and stubs on their scrolls. I had to add oil to two brand new 5hp scrolls during a recent start up process. Never would have known if those were hermetic recips.
Are you thinking the body would sweat and end where the warmer oil was in the sump?
I wonder if you were to flood the shell and then recover gas from the suction service valve if you would be able to see a sweat line from the bottom of the sump to the top of the oil level

[Zamoramax]

Oil level in a hermetic small ton compressor should not matter much as long as it is piped correctly. If we were to debate anything about a hermetic system would be the ability to change the oil should the system become acidic. The best way to get acid out of a system is to change the oil.

Please elaborate on this with a conventional system and say a 4 on 1 mini split. I have never had to change the oil. I am pretty sure I know what to do but want to verify.

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[pecmsg]

Copeland puts sightglasses and stubs on their scrolls. I had to add oil to two brand new 5hp scrolls during a recent start up process. Never would have known if those were hermetic recips.
Are you thinking the body would sweat and end where the warmer oil was in the sump?
I wonder if you were to flood the shell and then recover gas from the suction service valve if you would be able to see a sweat line from the bottom of the sump to the top of the oil level

Scrolls have very little oil in them to begin with. Whats the piping like where this oil had to be added?

[71CHOPS]

a hermetic recip is only gonna be used on fractional HP systems.

Those systems are usually so small, oil control isn't an issue.

technically, if you did flood one, then evacuate, the shell would ice at the liquid level.....but how accurate would that be, as it is oil AND refrigerant. you would have to watch it as you evacuated, and attempt to verify the liquid level once the ice melted, but still, I don't think you'd be able to get the exact level.

you could use the old trane screw method. put an access port lower than the expected oil level, get a hose with a sight glass, connect one end to that port, and the other to a port higher than that, then use the sight glass to see the level.

still though, unless it's a system with continuing failures, I don't think it's worth even caring what the level would be.

[TechmanTerry]

How do you torch a receiver tank? I have used a Heat Gun on the comp instead of the torch so as not to burn the oil. I did this 2-3-5 times in 5 decades.

[stumpdigger]

Copeland puts sightglasses and stubs on their scrolls. I had to add oil to two brand new 5hp scrolls during a recent start up process. Never would have known if those were hermetic recips.
Are you thinking the body would sweat and end where the warmer oil was in the sump?
I wonder if you were to flood the shell and then recover gas from the suction service valve if you would be able to see a sweat line from the bottom of the sump to the top of the oil level

Nice to know that the industry is keeping up with reality. Absolutely no thoughts on oil level based on sweating (I'm sure there is no data on the sweat line of a compressor) . I have worked on many semi-hermetics, and the way to get the acid out is to change the oil. (at least in the days of mineral oil)
The ability to change out POE oil would also aid in getting rid of water in a system. As I was taught, all the crap ends up in the oil pan.

[stumpdigger]

Please elaborate on this with a conventional system and say a 4 on 1 mini split. I have never had to change the oil. I am pretty sure I know what to do but want to verify.

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I'm not sure if I understand your question , or could explain it. Honestly I have no idea of what a mini split is unless it is a wallhanger evaporative unit. I have installed those. Thinking maybe

[stumpdigger]

Please elaborate on this with a conventional system and say a 4 on 1 mini split. I have never had to change the oil. I am pretty sure I know what to do but want to verify.

Sent from my SM-N960U using Tapatalk

" thinking maybe of a system larger than a mini-split, motor is burned out by acid, huge system... you cannot replace everything, so what we do is change the oil every day until acid tests come clear. The big question is what do we do with small time customers and tiny systems? I actually worked for two years maintaining window units, unfortunatly it useally costs more for repair than the unit it worth. IF you suffered a bad burnout in a mini split and have no ability to change the oil, you may have to replace the entire system.

[slctech]

Before installing the new compressor pour out the oil of the oil compressor you just cut-out of the suction. Or using a uni-bit drill a hole in the old compressor and pour out and weigh the oil. New compressor will usually come with oil and usually you can research the amount it is shipped with with apps offered by Copeland and Tecumseh. Not sure about LG and other off the wall brands. In any case if the original compressor was 20 ounces and you poured and weighed out 10 ounces, then you know that there is another 10 ounces out there somewhere in the system, unless there was a leak at sometime. In any case, you know now to pour out 10 ounces of oil from your new compressor or what ever is equivalent.

Or you can sweat the damn thing, after the fact, but then what? Cut it out and drain more?

I truly only worry about oil issues if I come across a system that has been molested by many techs and the poor thing is on its third to tenth compressor. All them idiot techs beforehand just threw a new compressor on with all the factory oil still inside with no thought about the oil quantity left in the system from the previous compressor or compressors and wonder why the system is chewing up compressors. Oil is no different than liquid refrigerant, once drawn into the scroll or cylinder part of the compressor the laws of physics is going to take precedents and something is gonna give.

After a change-out, I have sat next to brand new semi-hermetic compressors for hours and drained gallons of oil after initial start-up, most recently a few weeks ago.

[Zamoramax]

So I'm referring to a conventional resi split system say 4 ton.. and a mini split(wall hung) thats a 3 ton up to 4 heads. I have the 5 head 3½ ton in our shop but you can smell the acid. It still works but not for long if the acid remains. Just wondering if there's a hvac hack to changing the oil without removing the compressor that I'm not aware of.

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[pecmsg]

I used to have a Suction pump and 2 plastic cylinders, and a long thin tube. Cut the suction line, insert tube and pump out the oil.

Found its just easier to cut the discharge as well and pour the oil out.

[idontgetit]

Without pulling the oil out and measuring it I am not sure any other method is going to get you the answer you seek.

Take a paint marker and draw a line on the comp anywhere you like on the bottom half, that’s your oil level is it ok????

If you think you seriously have excessive oil, pull the comp, drain the oil, nitrogen blow the lines and then factory charge with the ounces the mfg says.

On the hermetic the excessive oil if it was high enough to damage the comp would do so when they are putting it in or on the next couple of starts due to foaming. It’s simply a matter of where the gas enters the head, if the oil is above the suction port there isn’t going to be much of a time frame to it, the comp will grenade itself in pretty short order.

Oil slugging is a lot worse that refrigerant slugging.

[dave1234]

Or perhaps silver brazing a port near the oem oil level to check while the systems pumped down?
.

Just wondering where exactly said “OEM oil level” (NOT charge quantity) is specd on any can (less scrolls with sight glasses usually tandems with equalizers)? Never seen such a thing.

[dave1234]

Copeland puts sightglasses and stubs on their scrolls. I had to add oil to two brand new 5hp scrolls during a recent start up process. Never would have known if those were hermetic recips.
Are you thinking the body would sweat and end where the warmer oil was in the sump?
I wonder if you were to flood the shell and then recover gas from the suction service valve if you would be able to see a sweat line from the bottom of the sump to the top of the oil level

Had to add oil at start up??

[mohad_i]

hermetic compressors usually coming with oil sight glass. (very small capacity for few and fractional horse power dont).
for small sized compressor no worries about the oil immigrating in the system and compresser run hot.. small and short pipes/no long rizer/small size coil.

in case of flashing the system, so would be better to get rid of all old oil and fill it again with manufacturer recommendation amount

[slctech]

Not a fan of immigrant oil.

[dave1234]

[QUOTE=nitrogen blow the lines [/QUOTE]

Personally I’ve never had luck with this. Wondering if anyone else has. The oil just clings to the piping walls in my past efforts- but that was before I learned the how and why and prescribed medicine to evap oil logging in the first place was only reason I tried. Yes there’s flush but on a big system=big ???????