Modern Pump Selection Part 3: Impact of Constant Fixed Head On Pump BEP

Modern Pump Selection Part 3: Impact of Constant Fixed Head On Pump BEP

In our last blog we explained why in real life HVAC applications, variable speed pumps almost never operate at zero speed.  Even at no flow, the impeller must be spinning enough to produce some amount of pressure at the 2-way valve in order to quickly establish full flow at the critical circuit IF demand suddenly occurs. Here's a silly way to think about it....

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Modern Pump Selection Part 2: Theory Vs. Real World Operation of Variable Flow Pumping

Modern Pump Selection Part 2:  Theory Vs. Real World Operation of Variable Flow Pumping

In variable speed pumping systems, does zero load ever result zero pump speed?

Practically speaking, the answer is no.  In closed hydronic systems with 2-way valves there is almost always some amount of differential pressure created by continuous impeller rotation – even when....

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Solving Balance Issues with A Differential Pressure Controller

Solving Balance Issues with A Differential Pressure Controller

What are your options when unbalanced circuits in an existing hydronic system are creating comfort issues due to underflow or overflow through coils?  We just spent the last twelve blogs describing the various methods for balancing a start-up system but do those same methods apply to existing systems and retrofits? 

The short answer is....

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Condensing Boiler Plant Piping Design & Control Part 7: Calculating Boiler Cycle Time

How long should a boiler run before it cycles off? And how long should it stay off before it cycles back on? The answers to these questions will of course vary from system to system. As a general rule, the combination of boiler run time and off time should never be any less than 10 minutes. Under normal operating conditions, the run time will always be dictated by two factors....
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Condensing Boiler Plant Piping Design & Control Part 6: Boiler Cycling and Supply Delta T

Identifying the stop and start range of a boiler system is a critical first step in controlling boiler staging and/or sequencing. This range defines what the boiler supply temperature is at full fire and what the supply temperature is at no fire. It is commonly referred to as the boiler supply Delta T.
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