Replacement Parts

TECHNICAL DATA
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HYDRONIC SOLUTIONS CATALOG
barometric readings & atmospheric pressures corresponding to
different altitudes
altitude barometer reading atmospheric pressure boiling point
of water (°f)
feet meters in. hg. mm. hg. psia ft. water
-1000 -304.8 31.0 788 15.2 35.2 213.8
-500 -152.4 30.5 775 15.0 34.6 212.9
0 0 29.9 760 14.7 33.9 212.0
500 152.4 29.4 747 14.4 33.3 211.1
1000 304.8 28.9 734 14.2 32.8 210.2
1500 457. 2 28.3 719 13.9 32.1 209.3
2000 609.6 27.8 706 13.7 31.5 208.4
2500 762.0 27.3 694 13.4 31.0 207.4
3000 914.4 26.8 681 13.2 30.4 206.5
3500 1066.8 26.3 668 12.9 29.8 205.6
4000 1219.2 25.8 655 12.7 29.2 204.7
4500 1371.6 25.4 645 12.4 28.8 203.8
5000 1524.0 24.9 633 12.2 28.2 202.9
5500 1676.4 24.4 620 12.0 27.6 201.9
6000 1828.8 24.0 610 11.8 27.2 201.0
6500 1981.2 23.5 597 11.5 26.7 200.1
7000 2133.6 23.1 587 11.3 26.2 199.2
7500 2286.0 22.7 577 11.1 25.7 198.3
8000 2438.4 22.2 564 10.9 25.2 197.4
8500 2590.8 21.8 554 10.7 24.7 196.5
9000 2743.2 21.4 544 10.5 24.3 195.5
9500 2895.6 21.0 533 10.3 23.8 194.6
10000 3048.0 20.6 523 10.1 23.4 193.7
15000 4572.0 16.9 429 8.3 19.2 184.0
npsh (av)= H (atm) ±H (s)-h (vp), where:
H (atm) = lowest atmospheric pressure in feet absolute at
system location;
H (vp) = vapor pressure of liquid in feet absolute at highest liquid
temperature expected.
H (s) = suction pressure (+) or vacuum (-) in fleet at inlet of pump.
How to obtain lowest atmospheric pressure:
1 Determine average barometric pressure for location of pump.
Call weather bureau. Will be given in inch of mercury.
2 From 1, deduct ½ inch;
3 Multiply 2 by 1.13 to obtain H (atm)
Example:
Average barometric pressure = 30.2 inches of mercury.
H (atm)= (30.2- 0.5) × 1.13
= 29.7 × 1.13 = 33.6 feet
80
70
60
50
40
30
20
10
0
50 75 100125 150175 200225 250275 300
water temperature °f
vapor pressure psi
vapor pressure of water
in feet absolute