LG Warranty Scroll Compressor Replacement and Tear Down with Cause of Damage Found
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- เผยแพร่เมื่อ 30 ก.ย. 2024
- This videos shows how to replace a mechanically damaged scroll compressor on a Bryant condenser unit. The damage was from flood back causing debris from the bottom of the compressor to rise into the scroll and damage a critical port that maintains plate pressure. The compressor is a 3 ton LG APG029KAB
Good vid ! interesting how u figured how much oil was Left in the system. But removing oil from a New Compressor would make me worried about losing that new compressor. I would have just Blown the Lines and evap out with nitro & not messed with new compressors oil level. But thats just me. If it works for you. Then thats good. Good vid.
I know this compressor was going to be low because it was an oil pumper.
I was also thinking about it. Could it be that the comp failed due to low oil level? Was there any issue with this new compressor?
LG compressors just jam up not pistons fault. If that was Copland this wouldn't happen.
Maybe you are great at installation and operation, but you should maybe avoid declarations about the design of the internals. So many incorrect and misleading statements.
First, this LG is basically conceptual copy of a Copeland. As the Copeland patents ran out, LG simply copied their design and added features from other companies as well. Common practice...
1. The large "relief valve" in the high to low pressure barrier would be closed by the spring inside it. It is a safety device to prevent runaway pressure if discharge was blocked.
2. The small pressure valve in the "piston" is only to enable evacuation of cavity liquid that may finds it's way in, enabling excessive pressure to build during a flooded start.
3. The "piston" does help hold the scroll together with pressure that can vary by condition to only provide as much downward force as needed. Liquid in that "piston" cavity design has no where to go except the pressure relief valve. In Copeland compressors, the seals on the piston are designed to let excessive pressure (liquid) escape out as a form of protection.
4. The spring is not for shipping or packing... because all the discharge paths are closed by valves, it is likely to push down the piston to avoid the compressor from pulling a deep vacuum that would grind the scrolls together and damage them. These scrolls look undamaged.
5. Most scroll compressors today that are designed by copying a Copeland are able to handle liquid in reasonable amounts (no need for accumulator). They have the ability to unload the scrolls axially and radially, so liquid can pass through. Axial separation is part of the "piston" design and radial separation is enabled by the the device on top of the shaft that engages the scroll hub/bearing. A Copeland can handle quite large amounts of liquid (and debris), even though as an engineering principle, it should be avoided.
6. The two little valves on top of the scroll are for performance not sound. These allow the gas to escape the compression process at an earlier pressure ratio so no further additional work is done trying to compress beyond what is needed. They would likely be set to match the pressure ratio of the most common operating condition to help with operation cost. (least effort = least power draw = least cost to operate.) This is a pure copy of Copeland (VCR) and Danfoss (VVR) designs.
7. The little chip in the scroll near the hole where the "piston" gets fed, while possibly caused by some contour anomaly near the hole, likely had no measurable impact on the compressor and could be purely coincidental. Metal debris is unlikely to float up and get to this point.
8. The cavity below the "piston" does fill with pressure bled off the scroll pocket after the suction pocket closes. That pressure is part of what holds the scrolls together. That same pressure also pushes up the "piston" so the narrow top face contacts the high to low barrier plate forming a face seal to separate high pressure from low. There is an engineering balance to old that "piston" at the most beneficial pressure to provide proper loads and not cause damage.
9. It is highly doubtful that anything floated from below and plugged that little hole. If that happened, it would still be there because there is VERY LITTLE flow through that hole. Once the pocket fills, the pressure is maintained and no significant flow goes through the hole because there is no where for it to go and pressure is held.
10. You mention the hole showed "wear." How could it have any wear? Nothing touches it and actual flow is minimal and quite laminar. Those marks are from the crude drill used to make the hole. It is not precise, so it was likely drilled quickly.
11. There is one dark spot on the tip of the scroll if that is a step, i suspect excessive force holding the scrolls together and allowing the tips to wear down. that could explain leakage, high temperature, motor trips and ultimately failure. However, you never said what was wrong with the compressor? Did it run and produce no capacity? (leakage) Did it not turn on (bad motor), did it nuisance trip? What was it doing? From your video, I cannot see anything that would indicate the capacity would be low. you would look for abnormal signs of tip/flank/bearing wear, which you said looked normal. I think there is more to discover about why this one failed, possibly a system issue...
Had LG compressor ground out that was on a system only 6 years old. Prior to that breaker was buzzing intermittently every 20-30 seconds ( without tripping). Finally tripped and it was fried. Changed compressor and still buzzes faintly for half or even less of second when compressor kicks on, but does not buzz Intermittently like before. Now I’m worried it’s slowly getting fried again. Where is good place to look to see if there is electrical issue? Also added hard start and no change.
I assume you changed the contactor especially if the grounded compressor was tripping the circuit breaker. I would be suspicious of a wifi thermostat such as ecobee or nest.
thank you for video. why not get testo gauges to save your time.
all residential systems i install have more than 10 superheat. hers refrigerant test also calls for superheat well above 10 and proper subcooling. usually it is 14 on the bryant sticker.
superheat too low with new txv. not enough airflow?
I do use the small wireless Testo pressure transmitter and my phone. I like that gauge because it doesn't lose any refrigerant from the system and goes in my tool bag. 5 degree superheat means the evaporator is nearly flooded and has the max capacity. 0 degree superheat means the evaporator has spill over.
Hey nate, would you be up for a video interview with me on what people need to know about R-22? There's a lot of misconceptions in the market right now. I work for a home inspection company and would love to get your opinion.
LG scrolls are junk... Rheem was using some at some point... we replaced the LG under warranty with a replacement LG and it failed within 3 months...warrantied the LG and got a Copeland... Been 5 years now... no issues
Lenox isn't even honoring their warranty on LG compressors or anything anymore. They were telling me that i have to prove that the home owner is the one who installed the system. Basically what they are say is if you bought a new house with an existing system that is only one year old they won't honor the warranty because your not the homeowner who installed it.
better change it with gree compressor than LG i have a bad experience with LG compressor they make so much heat that make the CRS socket melted so i change multiple times and the customer still complaint so i give them an old not to old copeland compressor and no issue at all.
I don't see them any more in Carrier units. I guess there were too many warranties.
Scroll compressors have a much higher tolerance to flood back than reciprocating. They have play inside that allows the moving parts to make way for the liquid. They can handle some liquid but not much. I've never had a problem out of a piston. In fact I remove many txvs and replaced with pistons and have seen much gains in cooling performance afterwards
That is cool. I like pistons better myself. The KISS principle says there is less stuff to break. Maybe this failure was a fluke. I will do a video on a copeland scroll failure when I see one that is mechanical.
I agree. I attended a Copeland compressor class where the instructor said nearly impossible to slug a scroll with refrigerant. That said, haven't seen it in the field either. As for the piston expansion to TXV, not my preference. TXV's work great in low demand cool environments and gives better efficiency in temperature ranges, like coastal areas, but in the hot desert/constant high heat load, a piston is a work horse with maximum (steady) feed and nearly problem free, except for an occasional blockage with 10yrs+ use. As for TXV, seen more of those go bad, either sticky or bulb charge loss. It's all good, every tech has an opinion, just saying. As for this video, I am here wanting an opinion on an LG compressor, just installed an Ameristar package unit with an LG. In the past, I've installed LGs in place of the copeland scroll because they are less expensive. Up to now, haven't had a problem or callback for the past three years (I give one year warranties on all compressor installs, Copeland or LG) so I learned something from this video.
Good video, you know your stuff. Many of those older piston expansion units also utilized r22. They were solid, I’ve had 410a units drop a compressor from a return duct falling off in a hot attic over a weekend, but I’ve actually had very few issues. I watch my super heat like a hawk, because I dont want avoidable problems. Great video
No Acid test ????
I go by smell instead of acid tests. burnt systems really stink. Sometimes they even burn the hands.
Thanks Nathan. Maybe your best video yet. Amazing how one little chip reduced capacity so much. I had no idea discharge pressure was used to press the plates together. But when you think about it, it’s always just the right amount of pressure!
BTW, have you tried the “Copeland Mobile“ app for checking compressor capacity When troubleshooting? They have Lg compressors included.
Good video!
Nathan is amazing, I'm a customer of 10 years. I'm a pretty technical person but not in the hvac field, but I'm seen him be a magician! He can troubleshoot issues that multiple people, can't diagnose and he's very reasonable with people. I'm honored to have his phone number! Thanks Nathan for all you do!
Thanks for sharing this video I learned something new today. Keep up the great work ✌️
Replace it with a Copeland, not an LG! LG compressors have a much higher failure rate! I ain’t surprised that it failed because they are inferior to Copeland.
Warrant compressors are free. Carrier seems to have lg in half their units. I make sure to use expansion valve now. I do like copeland better. I will see if lg makes it 20 years.
Great observational video
Thanks for posting.
I am telling you all right now. LG compressors are BULLET PROOF. I have installed tons of them in chinese made condensers in units with zero issues. I have them running in commercial buildings running down to 0 with no cold weather kits.
That is good to know. However, i see less of them in carrier units this year. I have personally had 2 fail out of 10 installed. One in this video. The other seized up when it lost its oil from a leak at the evaporator suction line solder joint.
Which chinese condenser brands did you use LG compressors on?
Great video. You may have mentioned it but..... I'm a little confused. If the system was commissioned correctly, why would there be any liquid flood back? Is the commissioning information incorrect? Or was this liq. flooding due to low air flow? (dirty filter, etc..)
It obviously wasn't commissioned correctly, because the compressor failed. flooding was due to factory charge combined with fixed orifice metering device. It was probably 0.5 lbs over charged. Normally, this wouldn't be a problem with a larger compressor that could deal with the over charge. All future systems will have expansion valve and at least 5 deg F superheat.
@@NathansHVAC That was my point, it's not that it utilizes fixed bore metering, it's that the system was not setup correctly that allowed the liquid slugging that possibly killed the compressor.
Everyday I see tiny little scrolls humming along without any issue utilizing fixed bore metering, and none of them have accumulators.
Thanks..
LG compressors are not good
True!! LG compressors are a crappy Korean knockoff to Copeland Scrolls!
@@applianceman6009 yeah I always prefer Copeland scrolls
If it turned into a low capacity oil pump that means it was pumping the oil out low capacity in oversized refrigerant lines now because of the low capacity how much oil gets backed up and stored inside the evaporator ? How much oil was left in the evaporator on this last new compressor installation was already in there ?
I assume most of the missing oil was in the evaporator and condenser.