TM 9-4120-395-14&P
5-9. EVACUATING REFRIGERATION SYSTEM-Continued.
g.
Start vacuum pump and open ballast valve (on vacuum pump) one turn.
h.
Compound gage should read 29 to 30 inches hg of vacuum.
i.
Close vacuum/purge valve.
j.
Open charging valve and add refrigerant until compound and pressure gages read approximately 2 psig,
then close.
k.
Stop vacuum pump and close ballast valve.
I.
Allow refrigerant to remain in system for one hour.
NOTE
Refrigerant will act as a blotter for moisture. One hour is recommended time for maximum
moisture removal. Shorter blotting period could be used if it is known that system is relatively
dry.
m.
Open vacuum/purge valve.
n.
Repeat steps "g" thru "i" one time.
o.
Open vacuum/purge valve.
p.
Start vacuum pump and open ballast valve (on vacuum pump) one turn. Compound gage should read 29 to
30 inches hg of vacuum.
q.
Close vacuum/purge valve and compound gage valve.
r.
Stop vacuum pump and close ballast valve.
s.
5-14