Page 149 - HVAC Pump Handbook

Rishel_CH06.qxd 20/4/06 6:06 PM Page 146

HVAC Pump Performance

146 HVAC Pumps and Their Performance

200
3450
3450
RPM
RPM
175
1
1 /2 x 2 x 8, 2 x 2 1 /2 x 8,
7" DIA. 7 /2" DIA.
1
150
2900 2900
RPM RPM
3450
RPM
125
3450 2 x 2 /2 x 6,
1
PUMP TDH—FT. 100 5 /2" DIA. 2900
RPM
6" DIA.
1 x 2 x 6,
1

2900 RPM
RPM
75
1760
RPM

50

1760
1460 RPM
RPM
25

1460
RPM
0
0 50 100 150 200 250 300
PUMP—GPM
Figure 6.7 Best efficiency curves for small single-suction volute pumps.

point for all volute type pumps which constitute the bulk of HVAC
pumps.

6.2.7 Steep versus flat head-flow curves
There is much discussion in the industry as to when a pump head-
flow curve is steep or flat. If a pump head-flow curve rises more
than 25 percent from the design point to the shutoff head or no-flow

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