Install Instructions

35
IM-PR 566442 1114 (Design Manual)
Stock Code Speed Amps Watts HP
12126
HI 0.75 87 1/25
MED 0.66 80 1/25
LOW 0.55 60 1/25
Stock Code Speed Amps Watts HP
12127
HI 1.8 197 1/6
MED 1.5 179 1/6
LOW 1.3 150 1/6
Figure 1-27 Pump curves for the 12126 and 12127
pumps supplied by Viega
1.9.3 Using a pump curve
Pump curves help you to select a circulator based
on the feet of head expected at the design flow
rate. The selected pump must have a capacity
greater than or equal to the system flow rate and
a head greater than or equal to the total system
pressure drop. Derive the pressure drop from
Section 1.9.2, Pressure drop. Once these two
system characteristics are known, a pump curve
can be used to identify the best match for the
system. Follow the procedure below to select a
pump sourced from Viega:
1. Locate the pressure drop on the left vertical
axis.
2. Locate the total system ow rate on the
bottom horizontal axis.
3. Follow to the intersection of both variables.
4. Select a pump with a curve just higher than
this intersection. If there are multiple pumps
with curves higher than this point, then
consider selecting the pump with the lowest
Watts for the best energy performance. Large
commercial and industrial applications may
require larger pumps.
Example:
A system design calls for a circulator that can move
5 gallons per minute at a pressure drop of 10 feet
of head. Identify a Viega circulator that will satisfy
this application.
5. On the pump curve for model 12126, identify
the intersection of 10 feet of head on the
vertical axis and 5 gpm on the horizontal axis.
This point is below the medium speed curve,
which has a power consumption of 80 watts.
6. On the pump curve for model 12127, identify
the intersection of 10 feet of head on the
vertical axis and 5 gpm on the horizontal
axis. This point is below the low speed curve,
which has a power consumption of 150
watts.
7. Select model 12126, which will satisfy the
design objectives and save 70 watts during
its operation.
Without Check Valve
HI
MED
LOW
20
18
16
14
12
10
8
6
4
2
0
0 24681012141618
Head (ft)
Flow (GPM)
Without Check Valve
HI
MED
LOW
Head (ft)
Flow (GPM)
30
25
20
15
10
5
0
0510 15 20 25 30 35