Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72°F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56

Illustration GS-RA-56: the U.S. Coast Guard has not released this illustration.

Question

Using the illustrated chart giving the boiling point of moisture at various depths of vacuum, with an ambient temperature of 72&deg;F, what depth of vacuum would be associated with the BEST chance of achieving a dehydration evacuation with a deep vacuum pump? Illustration GS-RA-56

Illustration GS-RA-56: the U.S. Coast Guard has not released this illustration.

Accepted Answer

Option D: 29.99" Hg or 254 microns of Hg absolute. Deep dehydration of refrigeration systems requires pulling a high vacuum below 500 microns (specifically 254 microns of Hg absolute, corresponding to 29.99" Hg) to ensure all trapped moisture boils off at ambient temperatures and is successfully evacuated by the vacuum pump.