Emerson VILTER VSS Installation, Operation And Service Manual page 36

Section 3 • Installation
all the joints have been repaired and the system is consid-
ered "tight" the system may be tested with refrigerant.
Attach a drum of the refrigerant to be used in the sys-
tem and allow the gas to enter until a pressure of 5 psig
is reached.
Remove the refrigerant drum and bring the pressure
to the recommended test level with oil pumped dry ni-
trogen or CO . Then check the entire system again for
2
leaks, using a halide torch or electronic leak detector.
Be sure to check all flanged, welded, screwed and sol-
dered joints, all gasketed joints, and all parting lines on
castings. If any leaks are found, they must be repaired
and rechecked before the system can be considered
tight again, remembering that no repair should be made
to welded or soldered joins while the system is under
pressure.
CO Systems
2
A CO system will tend to be more prone to leaks due to
2
the higher working pressures and the smaller molecule
size, and therefore its leak detection should become a
regular maintenance procedure. For a charge size of
above 661 lbs, for example, the recommendation would
be to perform the leak detection procedure about 4
times a year.
An oil stain will be a visual indicator of a CO leak, but
2
there are also leak detection sprays available in the mar-
ket (such as Weicon´s or Bulleye´s), infrared hand held
leak detectors (such as D-TEK CO ), and ultrasonic leak
2
detectors of several brands .
2
2 Information taken from Commercial CO2
Refrigeration Systems Guide for Subcritical and
Transcritical CO2 Applications, by Emerson.
3 – 14
VSS/VSR/VSM/VSH/VSSH Compressor • Installation, Operation and Service Manual • Emerson • 35391S