Copeland scroll failure

mejunkhound · 08-24-13, 07:13 PM

Finally got around to cutting the bottom off the compressor to look at the bottom bearing. Bearing itself good, bu--

Mystery solved - DEFECTIVE copeland assembly, screws attaching lower bearing to steel mounting plate shook out over time, allowing rotor to contact stator.

NO problems with oil or SSH or anything else, defective factory assembly -- e.g. they left the loctite off these screws?

There is a 3 tab bracket that is the lower bearing attachment, 3 ea specialty screws agttach the bearing to a steel plate - all 3 of those screws had shaken out over the last 15 years, allowing extra rotor play. I measured the journals and the shafts, < 3 mil clearance, typical of sleeve bearings, so no bearing wear to speak of. The lower bearing becomeing loos from the case allowed the play to let the rotor grind to a halt against the stator.

I hope the photos show up... They should be self explanatory, the steel mounting plate shows where the loose bearing oscillated till all 3 screw shook out, then there was enough play to lock the rotor.

Pictures did not copy, they are in the following link plus other details.

scroll compressor failures - Page 2

jeff5may · 08-25-13, 12:25 PM

Looks and sounds to me as if the compressor outlived its predicted age. I doubt the factory would consider this a freak failure: the unit did not fail in a violent or strange mode. Maybe some engineer would specify rivets or loctite, but I doubt it. The unit wasn't meant to be a brick.

Why is it that the pros at the other site poke sticks at everyone's problems? There is a huge amount of useful information circulated there, but one must wade through endless potshots and pious opinions to glean the gold. I understand they are skilled craftsmen who get lots of questions from lay persons, but they seem to treat each other the same way.

It seems the HVACR industry is this way in general, but it's really not...there are lots of awesome techs out there in the trenches. Plenty of problems are cured with only a single truck roll to a property. Tech shows up, tech diagnoses and repairs problem, tech goes on to the next one, no more problems for 5 to 10 years. Customer is happy and doesn't feel demeaned in any way.

AC_Hacker · 08-25-13, 01:07 PM

Quote:

Originally Posted by jeff5may

...they seem to treat each other the same way...It seems the HVACR industry is this way in general...Tech shows up, tech diagnoses and repairs problem, tech goes on to the next one, no more problems for 5 to 10 years. Customer is happy and doesn't feel demeaned in any way.

jeff5may,

I think you have put your finger on a widespread problem, the solution of which could result in HUGE opportunity for someone willing to step in and replace the current culture of third-rate work and crappy attitudes with solid standards and strong guarantees.

-AC

Xringer · 08-25-13, 01:52 PM

"defective factory assembly". It happens all the time at auto plants. Even the good ones. Like Mitsubishi DSM etc.
Seems like there's a lemon in every basket sometimes. Just luck not to get one.

mejunkhound · 09-02-13, 12:22 PM

Received feedback from Emerson (Copeland).

They had not seen this failure before in their lab even though they had run units with the screw left off. Told them, well, you have a failure like this now to add to your praeto charts.

Looks like it take a few years to loosen the screws and for the bearing mounting to wear enough for stator/rotor contact = LRA

Replaced the compressor with a 2 T vs. original 4T, so now I have very 'oversized' evap and condensor. Will see how much my COP has improved when it starts getting cold again.

May need to re-adjust my crossover where I switch to the GSHP heat pump, had it at 44F last year, maybe drop that a few degrees.

08-24-13, 07:13 PM	#1
mejunkhound Apprentice EcoRenovator Join Date: Apr 2011 Location: PNW Posts: 197 Thanks: 0 Thanked 47 Times in 31 Posts	Copeland scroll failure Finally got around to cutting the bottom off the compressor to look at the bottom bearing. Bearing itself good, bu-- Mystery solved - DEFECTIVE copeland assembly, screws attaching lower bearing to steel mounting plate shook out over time, allowing rotor to contact stator. NO problems with oil or SSH or anything else, defective factory assembly -- e.g. they left the loctite off these screws? There is a 3 tab bracket that is the lower bearing attachment, 3 ea specialty screws agttach the bearing to a steel plate - all 3 of those screws had shaken out over the last 15 years, allowing extra rotor play. I measured the journals and the shafts, < 3 mil clearance, typical of sleeve bearings, so no bearing wear to speak of. The lower bearing becomeing loos from the case allowed the play to let the rotor grind to a halt against the stator. I hope the photos show up... They should be self explanatory, the steel mounting plate shows where the loose bearing oscillated till all 3 screw shook out, then there was enough play to lock the rotor. Pictures did not copy, they are in the following link plus other details. scroll compressor failures - Page 2

08-25-13, 01:52 PM	#4
Xringer Lex Parsimoniae Join Date: Feb 2009 Location: Woburn, MA Posts: 4,918 Thanks: 114 Thanked 250 Times in 230 Posts	"defective factory assembly". It happens all the time at auto plants. Even the good ones. Like Mitsubishi DSM etc. Seems like there's a lemon in every basket sometimes. Just luck not to get one. __________________ My hobby is installing & trying to repair mini-splits EPA 608 Type 1 Technician Certification ~ 5 lbs or less..

08-25-13, 12:25 PM	#2
jeff5may Supreme EcoRenovator Join Date: Jan 2010 Location: elizabethtown, ky, USA Posts: 2,428 Thanks: 431 Thanked 619 Times in 517 Posts	Looks and sounds to me as if the compressor outlived its predicted age. I doubt the factory would consider this a freak failure: the unit did not fail in a violent or strange mode. Maybe some engineer would specify rivets or loctite, but I doubt it. The unit wasn't meant to be a brick. Why is it that the pros at the other site poke sticks at everyone's problems? There is a huge amount of useful information circulated there, but one must wade through endless potshots and pious opinions to glean the gold. I understand they are skilled craftsmen who get lots of questions from lay persons, but they seem to treat each other the same way. It seems the HVACR industry is this way in general, but it's really not...there are lots of awesome techs out there in the trenches. Plenty of problems are cured with only a single truck roll to a property. Tech shows up, tech diagnoses and repairs problem, tech goes on to the next one, no more problems for 5 to 10 years. Customer is happy and doesn't feel demeaned in any way.

09-02-13, 12:22 PM	#5
mejunkhound Apprentice EcoRenovator Join Date: Apr 2011 Location: PNW Posts: 197 Thanks: 0 Thanked 47 Times in 31 Posts	Received feedback from Emerson (Copeland). They had not seen this failure before in their lab even though they had run units with the screw left off. Told them, well, you have a failure like this now to add to your praeto charts. Looks like it take a few years to loosen the screws and for the bearing mounting to wear enough for stator/rotor contact = LRA Replaced the compressor with a 2 T vs. original 4T, so now I have very 'oversized' evap and condensor. Will see how much my COP has improved when it starts getting cold again. May need to re-adjust my crossover where I switch to the GSHP heat pump, had it at 44F last year, maybe drop that a few degrees.