CVHE teardown

[unitedchiller]

I am in the process of tearing down a 500 ton CVHE and found an unusual wear pattern on the back side of the 2nd stage diffuser plate seemingly from the some of the vanes on the 3rd stage shroud and vane assembly. The wear pattern is not uniform and appears in ~75 degree sections at 3 o'clock and 9 o'clock. Is this normal?

Also, are the diffuser plates aluminum or stainless steel? They look Aluminum to me but I'm not sure. My latest oil sample analysis revealed a high Aluminum count and I am thinking this is where it came from since there is no abnormal wear on the impellers or labys.

Lastly, the drive end journal bearing was wiped. Any ideas what would cause this aside from insufficient lubrication?

[Screwit]

CVHE diffuser plates are aluminium, difficult to comment on the wear pattern and bearing wiping wouthout photo's so only guessing.

Suspect the vane bushings/bearings are worn out where you are seeing the wear on the diffuser, it would be more typical to see even wear so could of been a problem with vane set-up/drive stroking. The unusual wear pattern is it circular from the vanes free spinning?

Bearing wiping/smearing with the absence of heat discolurisation indicates high refrigerant concentration in the oil to me, lubrication is lost as the refrigerant evaporates from the heat.

Need some photos for valid comment

[supertek65]

could you post some photos???????????????

[unitedchiller]

I will take some pictures today and post them ASAP.

[rover]

You would have heard a rattle/ hum at the 2nd stage end if the igvs are lazy when chiller was running. Sounds like oil pressure loss or bearing failure at drive end and and she smashed up. How were seals looking on the way through . Without photos cant say much though. If you have air in these machines oil is lost quite quickly.

[txhvac]

I would agree that the journal bearing got wiped from oil pressure, too much refrigerant, and excessive air all play apart. What vintage is this machine? Do you have any history?

[unitedchiller]

Finally got the pics....

Can anyone tell me if these wear patterns are normal? The first picture shows the back side of the second stage diffuser plate. The secnd picture shows some unusual dark spiraling around the center of the 3rd stage shroud and vane assembly. And the third picture shows what looks to be abnormal wear at the center each of the third stage vanes. It almost looks like the vanes are wearing through to the bore. Any ideas?

[acjourneyman]

Diffuser plate doesn't look like a big deal, factory grind marks it looks like.Don't know what stained the plate, and the vanes do look worn through. I would just clean up the plate and rebuild the vanes, was the acid level low in the past, or was the machine a leaker.

[txhvac]

How easy were the third stage vanes to operate by hand? How hard is it clean the stains of the vane plate? Where all the seals in good shape? I guess I'm not real sure either.

[rover]

Wouldn't be to concerned about diffuser plate, rebuild both igv assemblies, have had refrigerant meet its critical point in the past, freon fire, who knows though???