User Guide

Application guidelines
47AB237986441643en-US0701
System pressure test
Pressurize the system on HP side rst then LP side
to prevent rotation of the scroll. Never let the
pressure on LP side exceed the pressure on HP
side with more than 72 psi.
On SY/SZ240-300 models which have an
internal non return-valve in discharge tting
or if an external non return valve is present on
the discharge line, we advise to pressurize the
system not quicker than 70 psi/s to allow enough
pressure equalisation between LP and HP side
over the scroll elements.
Always use an inert gas such as nitrogen for
pressure testing. Never use other gasses such as
oxygen, dry air or acetylene as these may form
an inammable mixture. Do not exceed the
following pressures:
Moisture obstructs the proper functioning of the
compressor and the refrigeration system.
Air and moisture reduce service life and increase
condensing pressure, and cause excessively high
discharge temperatures, which can destroy the
lubricating properties of the oil. Air and moisture
also increase the risk of acid formation, giving
rise to copper platting. All these phenomena
can cause mechanical and electrical compressor
failure.
For these reasons it’s important to perform a
vacuum dehydration on the system to remove
all residual moisture from the pipe-work after
assembly;
SM / SY / SZ compressors are delivered with
<100ppm moisture level. The required moisture
level in the circuit after vacuum dehydration must
be < 100 ppm for systems with an SM / SY / SZ.
• Never use the compressor to evacuate the
system.
• Connect a vacuum pump to both the LP & HP
sides.
• Evacuate the system to a pressure of 0.02 inHg
(300 μm Hg) absolute.
Do not use a megohm meter nor apply power to
the compressor while it’s under vacuum as this
may cause internal damage.
Vacuum evacuation and
moisture removal
The compressor has been strength tested and
leak proof tested (<3g/year) at the factory.
• Always use an inert gas such as Nitrogen or
Helium
• Pressurize the system on HP side then LP side
• Do not exceed the test pressures indicated in
the previous section “System pressure test”
Leak detection
Maximum compressor test pressure (low side) SM/SZ 084 - 185: 363 psig SY 240 to 380: 319 psig
Maximum compressor test pressure (high side) 464 psig
Maximum pressure dierence between high and
low side of the compressor:
348 psig
Installation