7
Helpful Hints
Why Should You Use a High Vacuum Pump?
Air Conditioning and Refrigeration systems are designed and tested to operate at their most efficient only
when they are completely evacuated and charged with virgin refrigerant. Any moisture left in a system
before it is charged will decrease the system’s efficiency and can lead to system damage and potentially
system failure.
Damage caused by moisture is one of the leading causes of failures in AC/R systems.
Moisture
combines with refrigerants to create acids that corrode copper plating inside the system. Refrigeration
oil readily absorbs water and can turn into a sludge, losing its lubricating ability. The only way to remove
moisture from a system is to completely evacuate the system and pull a deep vacuum throughout the
entire system.
As the pressure in a system decreases, the boiling point of water also decreases. The following chart
shows that you can get water to boil at 72° F by creating a vacuum of 29.12 Inches Hg (just over 20,000
microns) in a system.
Temperature in °F
Inches of Mercury
Microns*
Pounds/Sq. In. (Pressure)
212°
0.00
759,968
14.696
205°
4.95
535,000
12.279
194°
9.23
525,526
10.162
176°
15.94
355,092
6.866
158°
20.72
233,680
4.519
140°
24.04
149,352
2.888
122°
26.28
92,456
1.788
104°
27.75
55,118
1.066
86°
28.67
31,750
.614
80°
28.92
25,400
.491
76°
29.02
22,860
.442
72°
29.12
20,320
.393
69°
29.22
17,780
.344
64°
29.32
15,240
.295
59°
29.42
12,700
.246
53°
29.52
10,160
.196
45°
29.62
7,620
.147
32°
29.74
4,572
.088
21°
29.82
2,540
.049
6°
29.87
1,270
.0245
-24°
29.91
254
.0049
-35°
29.915
127
.00245
-60°
29.919
25.4
.00049
-70°
29.9195
12.7
.00024
-90°
29.9199
2.54
.000049
Vacuum Gauge Placement
For a system to be adequately dehydrated, a deep vacuum must be achieved throughout the entire system,
not just the point where the vacuum pump is connected. For the most accurate reading of vacuum depth
throughout the system, it is recommended that you attach a vacuum gauge at an access port on the system
that is farthest from the TEZ8.
*Remaining pressure in system in microns.
