Danfoss PSH051, Инструкции по применению

Страница: 46 / 60

Application guidelines
46
FRCC.PC.021.A5.22
Installation
Brazing and soldering
Copper to copper Connections
Dissimilar metals Connection
Do not bend 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 section “Compressor connection”.
When brazing copper-to-copper connections,
the use of copper/phosphorus brazing alloy
containing 5% silver or more with a melting temperature of below 1472°F is recommended.
No flux is required during brazing.
When manipulating dissimilar metals such as
copper and brass or steel, the use of silver solder
and anti-oxidant flux is necessary.
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 on next pages.
Never drill holes into parts of the pipe-work
where filings and particles can not be removed.
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 polyolester oil
in R410A compressors requires that the oil be
exposed to the atmosphere as short 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.