Danfoss R134a Application Manuallines Download Page 43

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Installation

Compressor holding

charge

Each compressor is shipped with a nominal dry
nitrogen holding charge between 0.3 and 0.7 bar
and is sealed with elastomer plugs.

Before the suction and discharge plugs are
removed, the nitrogen holding charge must be
released via the suction schrader valve to avoid
an oil mist blowout. Remove the suction plug

first and the discharge plug afterwards. The plugs
shall be removed only just before connecting the
compressor to the installation in order to avoid
moisture from entering the compressor. When
the plugs are removed, it is essential to keep the
compressor in an upright position so as to avoid
oil spillage.

System cleanliness

The refrigerant compression system, regardless
of the type of compressor used, will only provide
high efficiency and good reliability, along with a
long operating life, if the system contains solely
the refrigerant and oil it was designed for. Any
other substances within the system will not
improve performance and, in most cases, will be
highly detrimental to system operations.

The presence of non-condensable substances
and system contaminants, such as metal
shavings, solder and flux, have a negative
impact on compressor service life. Many of
these contaminants are small enough to
pass through a mesh screen and can cause
considerable damage within a bearing assembly.
The use of highly-hygroscopic polyester oil in SZ
compressors requires that the oil be exposed to
the atmosphere just as little as possible.

System contamination is one of main factors
affecting equipment reliability and compressor
service life. It is important therefore to take
system cleanliness into account when assembling
a refrigeration system.

During the manufacturing process, circuit
contamination may be caused by:
• Brazing and welding oxides,
• Filings and particles from the removal of burrs in
pipe-work,
• Brazing flux,
• Moisture and air.

Consequently, when building equipment
and assemblies, the precautions listed in the
following paragraphs must be taken.

Tubing

Only use clean and dehydrated refrigeration
grade copper tubing. Tube cutting must be
carried out so as not to deform the tubing
roundness and to ensure that no foreign debris
remains within the tubing. Only refrigerant-grade
fittings should be used and these must be of

both a design and size to allow for a minimum
pressure drop through the completed assembly.
Follow the brazing instructions next pages.

Never drill holes into parts of the pipe-works
where fillings and particles can not be removed.

Do not blend the compressor discharge or
suction lines or force system piping into the
compressor connections, because this will
increase stresses that are a potential cause of

failure. Recommended brazing procedures and
material, are described on following page. Never
drill holes into parts of the pipe-works. Where
fillings and particles can not be removed.

Brazing and soldering

Copper to copper

connections

When brazing copper-to-copper connections,
the use of a copper / phosphorus brazing alloy
containing 5% silver or more with a melting

temperature of below 800°C is recommended. No
flux is required during brazing.

Mounting of SY 240-300-380

: the required bolt

size is HM10. The minimum required flat washer
outside diameter is 27 mm. Mounting bolts
must be tightened to a torque of 40 Nm. These
bolts and washers are not supplied with the
compressor.

Note

: The large flat washer must be positioned

in place before shipping the unit with the
compressor installed.

Note

: for parallel assemblies see specific

recommendations in Danfoss parallel application
guidelines, FRCC.PC.005.

Dissimilar metals

connection

When manipulating dissimilar metals such as copper and brass or steel, the use of silver solder and
anti-oxidant flux is necessary.

Lock washer *

HM 10 Bolt *

Large flat *