Refrigerant Oil

[vegasm]

During home renovations a worker punctured the liquid line near the evap coil and caused a complete loss of R22. Fortunately, he turned off the ac before all of the refrigerant escaped so I don't expect the compressor was damaged. The AC Tech repaired the puncture and will install a liquid line filter and recharge the system tomorrow. I noticed a large puddle of oil (at least 8 oz) at the leak and I asked the AC Tech how he was going to determine how much oil to add back into the system. He said he's going to take a best guess approach since the compressor is hermetically sealed and the only other option would be to disconnect, drain, and then refill it with oil. He also said that a few ounce too much or too little would not damage the system.

Maybe I'm being too cautious but I want to make sure the system is repaired correctly. Also, I wasn't expecting so much oil to be present on a split system with the evap coil 20 feet above the condenser. FYI, It's a Lennox 13ACC 4 ton unit with just under 9lbs and 14oz of R22 and a factory charge of 42oz of mineral oil (according to the faceplate). With a total loss of refrigerant, is there any way to addequately determine how much oil the tech should add back?

[docholiday]

I would first ask how you determined it was 8 ounces. Oil spreads very thin and a little looks like a lot. Feel free to pur a cap full of motor oil on your concrete driveway and see how big the spot gets.

If, on the other hand, it is pooled, then you might have a valid guess. The tech can then ad 8 ounces or close. The problem is that the oil is suspended in the refrigerant and likely all that pooled is not an accurate guess either.

I'd say, your tech is doing all he can do. If you would like to pay him to pump the system down, then recover the refrigerant, then pull the compressor, drain it, measure it and recharge it with the factory 42 ounces, then by all means go ahead. Refrigerant oil out in the system may come back to haunt you if you overcharge it with new oil. He'd then have to disconnect and flush the lineset, and coils to be sure none was left out.

Bottom line is, it's tough to tell how much oil the system has in it at this point. I suppose, if you wanted to you could simply replace the system.

[vegasm]

Docholiday, thank you for the reply! You're right, the 8 oz mention was just a guess based on a portion of it pooling. The tech said he couldn't be absolutely sure without a disco and reconnect of the compressor but he didn't think that was necessary. Do you feel it's worth the extra money for a disco? If no, is there anything I should watch for if the system has an undercharge or overcharge of oil? How many oz over or under would it take to experience problems and would it take days or years before a major failure?

Thanks again!

[star882]

Originally posted by vegasm
Docholiday, thank you for the reply! You're right, the 8 oz mention was just a guess based on a portion of it pooling. The tech said he couldn't be absolutely sure without a disco and reconnect of the compressor but he didn't think that was necessary. Do you feel it's worth the extra money for a disco? If no, is there anything I should watch for if the system has an undercharge or overcharge of oil? How many oz over or under would it take to experience problems and would it take days or years before a major failure?

Thanks again!
If there's too little oil, it would probably only last for minutes. If there's too much, there may or may not be immediate problems but efficiency and reliability might be affected.
BTW, couldn't you get the worker to pay for the repairs?

[vegasm]

The contractor is paying for everything except a compressor disco/reco since the AC Tech said it wasn't absolutely required. I'd be willing to pay extra or at least try to pressure the contractor to pay if I knew it was standard procedure to drain the oil after a total refrig loss. I've been unable to find any articles or forum posts addressing this issue.

[docholiday]

I would probably just leave well enough alone. I know that sounds bad, but that would be my recommendation.