ReplyA miniscule amount of oil comes out when evacuating the system.
Most of the oil is in the compressor. It's not a problem on residential systems.
Regular Guest
Goodman 4-ton condensing unit, Goodman 5-ton evaporator.
My 5 year old evaporator was replaced earlier this week (don't use clorox), and they had to evacuate the entire system because the service valve on the high-side line was stripped out. After the evaporator was installed, they removed both line driers (one was installed inside the condenser by the mfgr) and replaced them with only one. A vacuum was drawn, and then the system was recharged with R22. I have limited experience with automotive A/C systems, but shouldn't some oil have been added if the entire system was evacuated? I asked the A/C tech that question and he said that the R-22 acts as a lubricant when it becomes a liquid, but that doesn't make sense. All I know is that they had a large green canister of R-22; I don't know if that has any mixed in or not. Thanks.
Professional Member*
A miniscule amount of oil comes out when evacuating the system.
Most of the oil is in the compressor. It's not a problem on residential systems.
“I am for doing good to the poor, but...I think the best way of doing good to the poor, is not making them easy in poverty, but leading or driving them out of it. I observed...that the more public provisions were made for the poor, the less they provided for themselves, and of course became poorer. And, on the contrary, the less was done for them, the more they did for themselves, and became richer.”
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Professional Member
If charged properly you should not have a problem.
Regular Guest
removing both the factory installed drier and the external drier and replacing with a single new one is a good service practice that many do not take the time to do. Re-charging the oil on a hermetic resi system is rarely, almost never, needed. Sounds like your guy is at least in the upper 50% of the resi techs out there.
God Speed, Jim. We'll miss you - 2-26-23
Except for telling you the liquid r22 will lubricate the compressor, it sounds like you got a good tech.
4 ozs or less oil came out when they recovered your system. Nothing to worry about.
Professional Member
there is no oil in virgin 22.
Professional Member
The oil is distributed throughout the system when it is running.
Some oil is in the compressor, some in the condensor, evaporator, line set and driers.
There is no way to determine exactly how much oil is where when changing out an individual component.
Very little oil, if any, will be removed by the evacuation process. Vacumm pumps won't pull down to reach the vapor point of oil so it mostly stays put.
The entire system would have to be flushed to remove all the existing oil before the correct amount of oil could be added back in.
Otherwise adding oil would be just a 'guess' as to the amount to add.
The benefit is just not worth the effort in this case.
Some techs will choose an arbitrary amount depending on the component replaced but it is really an educated guess.
I like all the previous answers too.
Sounds like you're in good shape!
Professional Member*
Other than the tech not explaining how oil circulates inside a refrigeration system very well, sounds to me like he did good. I remember the days of purge n' gas it up...evacuate??? I now know better. EPA rules also changed things...in that respect, thankfully.
Psychrometrics: the very foundation of HVAC. A comfort troubleshooter's best friend.
Regular Guest
Guys,
Over the last few months, my compressor has gradually gotten louder, and now I'm noticing a metallic grinding noise for the first few minutes when it first kicks on. Prior to the service, it was quieter. Aside from the evaporator and the drier replacements, I had them install an expansion valve which he said would pose an additional load on the compressor (hot start also added), but will provide me with cooler air. I have noticed that despite my decreased running time, my electric load during the summer had increased. I am concerned that the louder noise during operation and the metallic noise when it first starts up is an indication that it is not getting properly lubricated. If this is the case, can oil charges be added much like automotive systems or is it an indication of permanent damage?
If oil is not the issue, what else can explain the louder noise or the grinding?
Regular Guest
Guys,
Over the last few months, my compressor has gradually gotten louder, and now I'm noticing a metallic grinding noise for the first few minutes when it first kicks on. Prior to the service, it was quieter. Aside from the evaporator and the drier replacements, I had them install an expansion valve which he said would pose an additional load on the compressor (hot start also added), but will provide me with cooler air. I have noticed that despite my decreased running time, my electric load during the summer had increased. I am concerned that the louder noise during operation and the metallic noise when it first starts up is an indication that it is not getting properly lubricated. If this is the case, can oil charges be added much like automotive systems or is it an indication of permanent damage?
If oil is not the issue, what else can explain the louder running noise or the grinding?
Regular Guest
Well, the tech came out and said the noise is an indication of an internal problem. It's also pulling about 6 amps more than what is stamped on the housing. He's going to look into an oil charge and talk with his peers; he also suggested that a crankcase heater MAY help extend the life if the issue is the returned R22 still liquid.
Suggestions?
God Speed, Jim. We'll miss you - 2-26-23
If the refrigerant is returning to the compressor as liquid. They should fine the cause. Its not suppose to be liquid when it gets to the compressor.
They might have it over charged.
Regular Guest
I don't know how much they put in, but I'm running 75 psi suction, and about 178 discharge. Is that too high?
Professional Member
Those pressures all depend on other conditions, indoor temp and outdoor temp,and filter condition, coil condition indoor and outdoor, fan speed and duct size and static pressure and and and and I could go on ............
Professional Member
If you are fishing on here for some reason to get us to say that the tech did something wrong, it wont happen from me. It sounds like he followed proper procedures, and adding oil to a residential system is not something that is typically done. There is not a way to know how much to add. Its all throughout your entire system. Adding oil may oil slug your compressor and make the life even shorter. how long did the system run on the old leaking evaporator before it was replaced. If there is compressor damage it most likely occured before they even touched the system, you are just now seeing the side effects. I feel like you are trying to find something the company did wrong so you will get a free compressor.
God Speed, Jim. We'll miss you - 2-26-23
As said earlier.
Those pressures mean nothing with out knowing the conditions at the time they were taken.
Regular Guest
one more voteOriginally Posted by a/c-harris
Regular Guest
No, there is no finger-pointing or blame. I do trust them; what started the whole discussion was when he told me R22 lubricated the compressor I felt I needed to check with others before signing off on the work.
I've been cleaning indoor and outdoor coils on my own since I bought the house new. The system is just over 5 years old, and the annual check by the A/C tech hasn't shown a problem until April of this year when he needed to add about a pound of R22. What they believe killed the evaporator was that the drain pan was angled down from the drain pipe, so that part of the coil sat in water the entire time (one side looked fine, the other was corroded. I also used a diluted bleach solution to keep the pipe clean, but since that also ran back to the pan, that helped speed up the corrosion.
Sounds like my concern about oil isn't valid, so I'm just trying to find other options before shelling out a few grand. Could the TXV introduce additional load? Could it have been charged higher than before; what would I observe if it was overcharged? Bottom line is if it's still cooling well is there anything I can do to help extend its operating life. If not, such is life. Thanks!
Member
for Houston, I would quess 70/210 if measured in the afternoon for this time of year -- 178 corresponds to an ambient of around 70 degrees with a condensor condensing 20-25 degrees above ambient -- normal conditions.
Professional Member*
Crankcase heater won't do anything to prevent floodback of liquid refrigerant. A crankcase heater is to prevent a condition where when a compressor starts, liquid refrigerant that has settled into the compressor oil sump while the compressor was off suddenly flashes into a vapor when the compressor starts, and washes oil off critical lubricating parts, such as bearings, valves, etc.
A TXV does not impose an undue additional load on a compressor. If the compressor is a reciprocating model it should have a start capacitor and potential relay installed to help the compressor start against a closed TXV at startup. A scroll compressor may not need this addition for a TXV.
Without being able to analyze your system first hand there's no sure fire way to ascertain your compressor's health from here. Just going by your words I'd say the poor thing is in trouble and may be headed to compressor heaven in the near future. And there may not be much to head it off...a replacement is the only solution...and at five years you MIGHT be under warranty on the compressor, but you might not as well, should you be just outside of five years.
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