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Adding Oil

48K views 27 replies 19 participants last post by  btjfitter  
#1 ·
Hello Everyone,

This only my second post and I am still a fairly new tech. In December I posted a question about a compressor leak at the Terminal plate. I received wonderful help and I was able to fix the leak. After fixing the leak on the compressor I vacuumed the system down and added 60 lbs of R-22. Now I notice the oil level is low (below 1/4 of sight glass).

The compressor is a TRANE CRHR40... With the compressor running is there a way to add new oil into the system?

Thanks for all the help
 
#3 ·
You can use an oil pump to get it in there, but it means pumping against the pressure in the system.... it's a PITA. Ideally, you add it while pulling a vacuum.
But, like GoCougs asked, are you sure the oil isn't the system?
 
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#13 ·
I like doing it this way as well. Vacuum pump does all the work for you. I keep a hose with an inline ball valve for just this purpose.
 
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#8 ·
isn't it dangerous to add oil during the vacuum procedure?with regard to moisture..
Typically, you're going to add it while doing a system evacuation after repairing whatever condition caused the oil loss (like a component change out or leak repair). After you minimize exposure to the atmosphere by bleeding the air out your hose, you add the oil once the system is at a slightly negative pressure. Then you continue pulling a vacuum to your target micron reading.
 
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#9 ·
I don't know where you are located and what your ambient conditions are but If I suspect low oil conditions I try to increase the load on the system and run it with hi head pressure. If it's r22 then block off part of the condensor to get 275 head pressure for a while then watch the oil glass. Many times logged oil will return, if it is logged. If it is low pumping it in by hand pump won't be hard plus you can see the level at the same time. This works fine if your adding to a small system and need to add a gallon or less. Pulling it in during evac works great if you know the exact amount to add.
 
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#10 ·
If the oil is at 1/4 of the oil sight glass, the system is in no danger. Compressor manufacturers charge the compressors with at least double the amount of oil required for a minimum, simply because oil travels with the refrigerant vapor and liquid. Make sure the oil sump heater is operational.
 
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#11 ·
The system is a closed loop. Once system equilibrium is achieved, the oil level in the sight glass should stay fairly constant as any oil that leaves the compressor comes back at the same rate. NEVER add oil to the system until you've determined why the level is low. Excess oil in the piping will result in an oil slug coming back to the compressor which will break rods and valves. My suggestion would be to see if the compressor is running fully loaded first. At this time of year, depending where you are, compressors may run unloaded more then loaded. If this is the case then the oil is stuck out in the system due to reduced gas velocities and will come back when the compressor is loaded. The 40 ton R model can have either 2 cylinder unloading or 3 cylinder unloading. Check to make sure that 1 or both coils are operational. If everything checks out, leave the level where it is because 1/4 of a sight glass is OK and ALOT better then too much oil when the fully loaded compressor brings it all back.
 
#12 ·
Thanks for all the help.

So, the compressor is new, after the compressor was installed I vacuumed the system down and added in 60 lbs of 22. I tried to start it up and found the one wire was reversed on the compressor during the install. The reversed wire caused the compressor to trip and it also caused a leak at the electrical terminal. I closed the isolation valves so it was isolated from the outdoor condenser, I recovered the refrigerant fixed and repaired the leak. Found out that the isolation valves do not quite work and I could not pull a vacuum. I recovered the remaining refrigerant in the system and during this there was a lot of oil that came out of my hoses. So I think during the recovery process and vacuuming some oil was removed.

I will watch the system when it loads up it is possible the oils is out in the system and just has not returned to the compressor.
 
#17 ·
If the leak was at the terminal plate and caused a oil loss at the glass, that terminal plate should have been dripping with oil. If you pulled that mucg oil through your hoses on recovering, your machine should have been rattling. If I could see oil in the glass id leave it myself. If your going to pump it in get a york style oil pump or a yellow jacket with the 1/2 tube attached. You'll be there all day playing with yourself using the little ones the go on top of gallon oil cans , JMO.

I don't get what you mean by the wire was reversed. Did someone swap two leads to reverse the rotation? I found on some of the old carlye racks windage from crank rotation would sometimes cause a little different oil level at the glass. Reversing it changed the level at the glass. These were the old HR chillers with 4 or 5 compressors and one with a odd ball oil level.
 
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