Question 67Refrigeration & AC - 1st Asst/Chief
70% to passUsing 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
A28.75" Hg gauge or 31,750 microns of Hg absolute
B29" Hg gauge or 25,400 microns of Hg absolute
C29.20" Hg or 20,320 microns of Hg absolute
D29.99" Hg or 254 microns of Hg absolute
AI Explanation
The correct answer is D) 29.99" Hg or 254 microns of Hg absolute. This is the correct answer because at a vacuum depth of 29.99" Hg or 254 microns of Hg absolute, the boiling point of moisture is the lowest, which would provide the best chance of achieving a dehydration evacuation with a deep vacuum pump. The illustrated chart shows that as the vacuum depth increases, the boiling point of moisture decreases, making it easier to remove moisture from the system. The other options, while also representing high vacuum levels, do not provide the absolute lowest boiling point of moisture compared to 29.99" Hg or 254 microns of Hg absolute.
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