INSTALLATION AND SERVICE
System pressure test
1-2-4 cylinder compressors
Maximum compressor test pressure, low side
362 psi(g)
Maximum compressor test pressure, high side
435 psi(g)
Leak detection
system is ready, the compressor caps
can be removed and the compressor
connected to the system with a mini-
mum exposure to ambient air.
If this procedure is not possible, the slee-
ves or valves may be brazed to the pipes
when mounted on the compressor.
In this situation nitrogen or CO
2
must be
purged through the compressor via the
Schräder valve to prevent air and mois-
ture ingress. Purging must start when
the caps are removed and continue du-
ring the brazing process.
When rotolock valves are used on
the compressor, they must be closed
immediately after mounting, thus kee-
ping the compressor isolated from the
atmosphere or from a system not yet
dehydrated.
Note:
When the compressor is built into
a ”rack” or “pack” configuration that is
not installed immediately in its final lo-
cation, a vacuum pull-down and mois-
ture removal must be performed to the
rack as if it were a complete system (see
below). The rack must be charged with
nitrogen or CO
2
and open tubes must
be blocked with caps or plugs.
It is recommended that an inert gas
or nitrogen be used for pressure tes-
ting. Dry air may also be used but care
should be taken since it can form a
flammable mixture with the compres-
sor oil. When performing a system
pressure test, the maximum allowed
pressure for the different components
should not be exceeded.
For MT/MTZ compressors the maxi-
mum test pressures are shown in the
table below.
Do not exceed 435 psig pressure dif-
ferential between high pressure side
and low pressure side of the compres-
sor because this will open the internal
compressor relief valve.
Whenever possible (if valves are pre-
sent) the compressor must be kept
isolated from the system. Perform
leak detection using the final refri-
gerant. Pressurize with nitrogen or
another system-neutral gas and use a
leak detector for the applied refrige-
rant. A helium leak detector can also
be used.
Leaks must be repaired respecting
the instructions written above. Use
of other gasses such as oxygen,
dry air, or acetylene is not recom-
mended, as these gasses can form a