Manitowoc UG018A, Technician'S Handbook

Page: 88 / 136

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A. Pull vacuum to 1000 microns. Break the vacuum
with dry nitrogen and sweep the system. Pressurize
to a minimum of .35 bar.
B. Change the vacuum pump oil.
C. Pull vacuum to 500 microns. Break the vacuum
with dry nitrogen and sweep the system. Pressurize
to a minimum of .35 bar.
D. Change the vacuum pump oil.
E. Pull vacuum to 500 microns. Run the vacuum pump
for 1 hour additional hour.
Charge the system with the proper refrigerant to the
nameplate charge.
Operate the ice machine for one hour. Then, check
the pressure drop across the suction line filter-drier.
F. If the pressure drop is less than .14 bar, the filter-
drier should be adequate for complete cleanup.
G. If the pressure drop exceeds .14 bar, change the
suction line filter-drier and the liquid line drier.
Repeat until the pressure drop is acceptable.
Operate the ice machine for 48-72 hours. Replace
the suction line and liquid line drier if necessary.
Important
Dry nitrogen is recommended for this procedure.
This will prevent CFC release.