Carrier CDII-184R1-0CTR4 Installation & Operation Manual page 29

Connect vacuum pump on liquid valve after nitrogen removal then vacuum to required vacuum
level of 500microns, automatically the vacuum pumps does the vacuum in both high side and
low side piping this will allow entire system to vacuum.
1) Perform the process after leak detection.
2) Pull down refrigeration circuit to a vacuum of 300 microns of Hg (0.40 mbar).
3) When a vacuum level of 300 microns of Hg is reached, circuit must be isolated from pump.
4) Wait for 30 minutes.
5) If pressure rapidly increases, then circuit is not leak tight. Locate and repair leaks. Restart
from step 1.
6) If pressure slowly increases, then circuit contains moisture. Break vacuum with dry nitrogen
gas and repeat steps 2 – 3 – 4.
A vacuum of 300 microns of Hg (0.40 mbar) should be reached and maintained lower than 500
microns for 1-hour minimum from both liquid & gas pipes. It will guarantee that circuit is both
tight and fully dehydrated. This pressure shall be measured at refrigeration system, not at
vacuum pump gauge.
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