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Figure 1
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Figure 2
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Figure 3
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One Less Circulator
A significant advantage of this approach over a parallel primary/secondary system is that it eliminates the need for a primary circulator. Not only does this reduce installation cost, it also reduces operating cost. Here's an example: Assume the primary circulator in a P/S system operates at 200 watts for 3,000 hours per year in a location where electricity currently costs 12 cents/ kilowatt•hour. The operating cost of this circulator at present would be:![](/PM/2006/11/Files/Images/PM-nov06-fig-4-sm.jpg)
Figure 4
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Figure 5