Alternatives To Bitzer Polyolester Oils; New Refrigerants With Low Gwp; Use Of Polyolester Oils With Chlorinated (H)Cfc Refrigerants (R22 Etc.); Critical Points - Bitzer BSE32 Informations Techniques

Diagrams can be used to read-off the refrigerant con-
tent in the lubricant depending on refrigerant pressure
and oil temperature

5 Alternatives to BITZER polyolester oils

NOTICE
!
!
Risk of compressor damage!
The use of the polyolester oils BSE32 and
BSE55 is mandatory for the running-in period of
the compressors.
Use only these BITZER polyolester oils for the
initial charge!
The two polyolester oils BSE32 and BSE55 are charac-
terised by specific tribological characteristics and have
special wear protection additives which increase the
service life of the compressor. Therefore, original poly-
olester oils from BITZER must be used for the initial
charge.
BITZER will only use BITZER polyolester oils for the
complex tests with regard to compatibility with new ma-
terials and refrigerants including unsaturated com-
pounds (HFO) such as R1234yf or R1234ze(E) and
mixtures containing them. In case of material changes
on products, only the BITZER polyolester oils will be in-
cluded in the tests.
The use of alternative oils whose characteristics corres-
pond largely to the original BSE32 or BSE55 charge is
only possible at the system owner's own responsibility.
It is also possible to mix them with the original oil,
within the respective viscosity group, as long as appro-
priate own or comparable experience is available for
the application concerned. Generally, mixing different
oil types may have a negative effect on the properties
of the oils.
The basic assumption for the use of alternative oils is
that the manufacturer or supplier guarantees the
product quality and the moisture content < 50 ppm.

6 New refrigerants with low GWP

Refrigerants which are new on the market, particularly
the unsaturated compounds R1234yf and R1234ze(E),
are highly soluble in oil and lead to a strong reduction
of viscosity. Therefore, sufficient superheat has to be
ensured! The low chemical stability results in a short at-
mospheric lifetime and therefore in a low greenhouse
potential GWP. These substances are the basis for
many new refrigerant mixtures with reduced GWP. The
stability, however, requires particular care regarding
KT-510-6
cleanliness, dryness and evacuation of the refrigerant
circuit.
The polyolester oils of BITZER are tested for use with
R1234yf, R1234ze(E) and mixtures containing them,
such as R448A, R449A, R450A, R452A and R513A,
and released for the respective application limits.
7 Use of polyolester oils with chlorinated (H)CFC
refrigerants (R22 etc.)
A trend also exists towards charging compressors with
polyolester oils for systems with (H)CFC refrigerants, to
simplify a subsequent conversion to chlorine-free refri-
gerants. Polyolester oils are generally suitable for such
applications, however, there is a significantly increased
risk regarding compressor wear and the chemical sta-
bility of the refrigerant circuit. This applies even though
BITZER compressors are constructed with high-quality
materials, such as surface hardened shafts, specially
treated bearings, hard chrome-plated compression
rings, valves made of stainless steel.
The argument that the conversion to alternative refri-
gerants is simplified is only valid with certain restric-
tions. A qualified conversion requires repeated oil
changes due to the unavoidable contamination of the
oil with chlorine from the (H)CFC refrigerant.
Information
Due to the special risks regarding polyolester
oils in (H)CFC refrigerant circuits, the evaluation
of a warranty claim in case of compressor dam-
age is subject to an individual inspection of the
compressor in the factory.

7.1 Critical points

The use of polyester oils in combination with (H)CFC
refrigerants should always be considered carefully es-
pecially regarding the following points:
Strong viscosity reduction
When using (H)CFC, the quantity of refrigerant dis-
solved in the polyolester oils is more than double as
with conventional lubricants or when operating with a
combination of polyester oils and chlorine-free HFC.
This results in a strong viscosity reduction and the
danger of increased wear, especially in cases of high
suction pressure and low oil temperature. The starting
procedure after long periods of standstill is particularly
critical.
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