What about the oil?

[Scott Buker]

I have several cascade systems with Copeland scroll compressors using R404 and R23. These reach a temperature of -60. Copeland says that their compressors aren't recommended for this temperature. The manufacturer says the system will work fine if I use a different oil (viscosity is the same). Currently, the manufacturer is making the systems using an ISO 32 oil with the R23. After suffering some compressor failures, I'm wondering if I need to use a thinner oil. Any Ideas? Thanks.

[nike123]

I think that Copeland guys know what are they talking.

What is compressor model# and how is cooled that compressor?

[Scott Buker]

These compressors are water cooled. The model # is ZF13K4E-TF5. These are in running systems. I have to get them running again. One company told me a add a small charge of propane to thin the oil and aid in return. I'm wondering about using a lower viscosity oil because of the low temp. Also, I've thought about changing to SUVA-95 to get a lower discharge pressure and temp so that the system could tolerate a lower viscosity oil.

[NoNickName]

Pentane, not propane... pentane is liquid at all times and miscible with POE.

[lowcool]

copeland have a twenty two weight oil

[R508Cascade]

Can you give the cause of the failures? Mechanical or
electrical? Was this chamber retrofitted from another
refrigerant? What size HP is the compressor?

I use copeland iso22 on all my low stage refrig sys.
with copeland compressors. I also add pentane
to the oil. This additive as said before keeps the
oil addmissive with refrigerant during low temps.


R-23 has a high discharge temp. I would make sure that the liquid injection valve on the low temp sys. is operating. Without this valve operating correctly the compressor eithers overheats or floods back causing
valve damage or bearing failures.

R-508 or Suva 95 has lower discharge temps if
you want to change refrigerant.

Notes:

1. Keep POE oil from air contact. This oil is very hygroscopic. (absorbs moisture)

2. Replace driers every time the system is opened!

3. Triple evac. sys with dry nitrogen breaks.

4. Both systems must be correctly running in order
for long term reliability. Check your high stage
system!

[R508Cascade]

Also,
Check the desuperheater on the low stage system. This is criticle on a R-23 system in order to reduce temp.
on the return gas. These usually
clog up within a couple of years
of use. I would also check the regulating water vavle for correct operations!

[Scott Buker]

The failure was mechanical. The compressor is 8 horsepower . This chamber has always been R23, new from the manufacturer (Japan).

[D.D.KORANNE]

try Fuchs Reniso SEZ 22 oil with R-23 .