YORK INTERNATIONAL
26
FORM 160.54-O2(1102)
FORM 160.54-O2(1102)
27
YORK INTERNATIONAL
VACUUM TESTING
After the pressure test has been completed, the vac-
uum test should be conducted as follows:
1. Connect a high capacity vacuum pump, with indi-
cator, to the system charging valve as shown in
Fig. 11 and start the pump. (See “Vacuum Dehy-
dration”.)
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. See Table 2 for corresponding 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.
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 vacuum
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.
Be sure the vacuum indicator is
valved off while holding the system
vacuum and be sure to open the
valve between the vacuum indicator
and the system when checking the
vacuum after the 8 hour period.
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.
TABLE 2 –
SYSTEM PRESSURES
*GAUGE ABSOLUTE
BOILING
INCHES OF TEMPERATURES
MERCURY (HG) MILLIMETERS OF
BELOW ONE PSIA OF MERCURY MICRONS WATER
STANDARD (HG) °F
ATMOSPHERE
0 14.696 760. 760,000 212
10.24" 9.629 500. 500,000 192
22.05" 3.865 200. 200,000 151
25.98" 1.935 100. 100,000 124
27.95" .968 50. 50,000 101
28.94" .481 25. 25,000 78
29.53" .192 10. 10,000 52
29.67" .122 6.3 6,300 40
29.72" .099 5. 5,000 35
29.842" .039 2. 2,000 15
29.882" .019 1.0 1,000 +1
29.901" .010 .5 500 –11
29.917" .002 .1 100 –38
29.919" .001 .05 50 –50
29.9206" .0002 .01 10 –70
29.921" 0 0 0
*One standard atmosphere = 14.696 PSIA
= 760 mm Hg. absolute pressure at 32°F
= 29.921 inches Hg. absolute at 32°F
NOTES: PSIA = Lbs. per sq. in. gauge pressure
= Pressure above atmosphere
PSIA = Lbs. per sq. in. absolute pressure
= Sum of gauge plus atmospheric pressure
Maintenance
