Vacuum Testing; Table 2 - System Pressures - York YK Series Operation And Maintenance

SECTION 6 - MAINTENANCE

TABLE 2 - SYSTEM PRESSURES

*GAUGE
INCHES OF
MERCURY (HG)
BELOW ONE
STANDARD
ATMOSPHERE
0
10.24"
22.05"
25.98"
27.95"
28.94"
29.53"
29.67"
29.72"
29.842"
29.882"
29.901"
29.917"
29.919"
29.9206"
29.921"
*One standard atmosphere = 14.696 PSIA
= 760 mm Hg. absolute pressure at 32°F
= 29.921 inches Hg. absolute at 32°F

VACUUM TESTING

After the pressure test has been completed, the vacuum
test should be conducted as follows:
1. Connect a high capacity vacuum pump, with in-
dicator, to the system charging valve as shown in
Figure 12 on Page 25 and start the pump. (Re-
fer to Vacuum Dehydration on Page 27.)
2. Open wide all system valves. Be sure all valves to
the atmosphere are closed.
3. Operate the vacuum pump in accordance with
VACUUM DEHYDRATION until a wet bulb
temperature of +32°F or a pressure of 5 mm Hg
is reached. Refer to Table 2 on Page 26 for cor-
responding values of pressure.
4. To improve evacuation circulate hot water (not
to exceed 125°F, 51.7ºC) through the evaporator
and condenser tubes to thoroughly dehydrate the
shells. If a source of hot water is not readily avail-
able, a portable water heater should be employed.
26
ABSOLUTE
MILLIMETERS OF
PSIA
MERCURY (HG)
14.696 760.
9.629 500.
3.865 200.
1.935 100.
.968 50.
.481 25.
.192 10.
.122 6.3
.099 5.
.039 2.
.019 1.0
.010 .5
.002 .1
.001 .05
.0002 .01
0 0
BOILING
TEMPERATURES
OF
MICRONS
WATER
°F
760,000 212
500,000 192
200,000 151
100,000 124
50,000 101
25,000 78
10,000 52
6,300 40
5,000 35
2,000 15
1,000 +1
500 –11
100 –38
50 –50
10 –70
0
NOTES: PSIA = Lbs. per sq. in. gauge pressure
= Pressure above atmosphere
PSIA = Lbs. per sq. in. absolute pressure
= Sum of gauge plus atmospheric pressure
DO NOT USE STEAM. A suggested method is
to connect a hose between the source of hot water
under pressure and the evaporator head drain con-
nection, out the evaporator vent connection, into
the condenser head drain and out the condenser
vent. To avoid the possibility of causing leaks, the
temperature should be brought up slowly so that
the tubes and shell are heated evenly.
5. Close the system charging valve and the stop
valve between the vacuum indicator and the vac-
uum pump. Then disconnect the vacuum pump
leaving the vacuum indicator in place.
6. Hold the vacuum obtained in Step 3 in the system
for 8 hours; the slightest rise in pressure indicates a
leak or the presence of moisture, or both. If, after 24
hours the wet bulb temperature in the vacuum indi-
cator has not risen above 40°F (4.4°C) or a pressure
of 6.3 mm Hg, the system may be considered tight.
7. If the vacuum does not hold for 8 hours within the
limits specified in Step 6 above, the leak must be
found and repaired.
FORM 160.76-O1
ISSUE DATE: 6/15/2015
WATER
FREEZES
JOHNSON CONTROLS