7
Refrigeration Oils*
With the changes that have taken place in our industry due to the CFC
issue, we have reevaluated our lubricants to ensure compatibility with the
new HFC refrigerants and HCFC interim blends offered by several chemical
producers. As a secondary criteria, it is also desirable that any new lubricant
be compatible with the traditional refrigerants such as HCFC-22 or R502. This
“backward compatibility” has been achieved with the introduction of the
Polyol ester lubricants.
Polyol Ester Lubricants
Hygroscopicity
Ester lubricants (POE) have the characteristic of quickly absorbing moisture
from the ambient surroundings. This is shown graphically in Figure 8 where
it can be seen that such lubricants absorb moisture faster and in greater
quantity than conventional mineral oils. Since moisture levels greater
than 100 ppm will results in system corrosion and ultimate failure, it is
imperative that compressors, components, containers and the entire system
be kept sealed as much as possible. Lubricants will be packaged in specially
designed, sealed containers. After opening, all the lubricant in a container
should be used at once since it will readily absorb moisture if left exposed to
the ambient. Any unused lubricant should be properly disposed of. Similarly,
work on systems and compressors must be carried out with the open time as
short as possible. Leaving the system or compressor open during breaks or
overnight
MUST BE AVOIDED!
Figure 8.
Color
As received, the POE lubricant will be clear or straw colored. After use, it may
acquire a darker color. This does not indicate a problem as the darker color
merely reflects the activity of the lubricant's protective additive.
Oil Level
During Copeland's testing of Polyol ester oil, it was found that this lubricant
exhibits a greater tendency to introduce oil into the cylinder during flooded
start conditions. If allowed to continue, this condition will cause mechanical
failure of the compressor.
A crankcase heater is required with condensing units and it must be turned
on several hours before start-up.
Oil level must not exceed 1/4 sight glass.
Oil Types
Table 2 below summarizes which oils/lubricants are approved for use in
Copeland compressors.
Mineral Oils
The BR and Scroll compressors use Sontex 200, a “white oil”. This oil is
not suitable for low temperature applications nor is it available through
the normal refrigeration wholesalers. For field “top-off” the use of 3GS or
equivalent, or Zerol 200TD is permissible, as long as at least 50% of the total
oil charge remains Sontex 200.
Suniso 3GS, Texaco WF32 and Calumet R015 (yellow oils) are available
through normal refrigeration wholesalers. These oils are compatible if mixed
and can be used on both high and low temperature systems.
Polyol Ester Lubricants
The Mobil EAL ARCTIC 22 CC is the preferred Polyol ester due to unique
additives included in this lubricant. ICI Emkarate RL 32S is an acceptable
Polyol ester lubricant approved for use when Mobil is not available. These
POE’s
must
be used if HFC refrigerants are used in the system. They are
also acceptable for use with any of the traditional refrigerants or interim
blends and are compatible with mineral oils. They can therefore be mixed
with mineral oils when used in systems with CFC or HCFC refrigerants when
Copeland compressors are used. These lubricants are compatible with one
another and can be mixed.
Alkyl Benzenes
Zerol 200TD is an alkyl benzene (AB) lubricant. Copeland recommends this
lubricant for use as a mixture with mineral oil (MO) when using the interim
blends such as R-401A, R-401B and R-402A (MP39, MP66 and HP80). A
minimum of 50% AB is required in these mixtures to assure proper oil return.
Shell MS 2212 is a 70/30 mixture of AB/MO. If this lubricant is used in a
retrofit situation virtually all of the existing MO must be drained prior to
refilling with the MS 2212 to assure a minimum 50% AB content.
Table 2. Refrigeration Oils
Refrigeration Oils
Traditional Refrigerants
HCFC-22
Interims
R01A, R01B, R02A
(MP-9, MP-, HP-80)
HFC's
HFC-1a, R0A, R507
POE's
Mobil EAL ARCTIC 22 CC
A
A
P
ICI (Virginia KMP) EMKARATE RL 32CF
A
A
P
Mineral Oils
Suniso 3GS
P
PM
NOT ACCEPTABLE
Texaco WF32
P
PM
Calumet RO15 (Witco)
P
PM
Sontex 200-LT (White Oil)
(BR & Scroll Only)
Witco LP-200
P
A/B
Zerol 200TD
AM
PM
NOT ACCEPTABLE
Soltex Type AB-200
PM
P = Preferred Lubricant Choice A = Acceptable Alternative M = Mixture of Mineral Oil and Alkyl Benzene (AB) with minimum 50% AB.
*(Reprinted by permission from Copeland Corporation)