Circulator Sizing - Westinghouse WBCETNG750 Manual

G. Circulator Sizing
In addition, the boiler heat exchanger has a minimum total water volume that must be taken into account when sizing the
circulator. Minimum boiler flow rates are listed in the table below.
Model
750
1000
Table 3 - Minimum Flow Rates
The boiler heat exchanger does have a pressure drop which must be considered in system design. Refer to the graph in Table 4
for pressure drop through the boiler heat exchanger.
Table 4 - Heat Exchanger Pressure Drop
The chart below represents various system design temperature rise through the boiler along with respective flows and friction
loss. This is provided to aid in circulator selection.
Model Friction Ft
750 2.85'
1000 1.85'
Table 5 - Temperature Rise, Friction Ft and Flow Rate
Minimum Boiler Flow Rates
System Temperature Rise Chart
20°Δt
Flow Rate (GPM) Friction Ft
75
100
Minimum Flow (GPM)
7.5
10
25°Δt
Flow Rate (GPM)
1.8' 60
1.25' 80
30°Δt
Friction Ft Flow Rate (GPM)
1.3' 50
0.8' 66.6
WHL-038 Rev. 1.29.16
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