To control a variable speed pumping system, we must determine the minimum operational head of the system. Some refer to this value as constant head, minimum head, independent head, etc. Throughout this and in other JMP blogs, we refer to it as ...Read More
In our last blog, we cautioned against using pressure independent control (PIC) valves when attempting to apply area control with reset. But why is that a problem? Aren’t PIC valves the greatest thing since microwave ovens?...Read More
We call him Mr. Creep.
Mr. Creep is not an actual person but rather a phenomenon of an ever-increasing control head in a variable speed pumping system caused by frequent incidents of underflowing coils, the result of which is progressive increases in operating cost and potential non-compliance....Read More
We’ve been talking about variable speed control since September 11, 2017, beginning with this blog ASHRAE 90.1-2010/2013: Impact on Variable Speed Pump Control in Chilled Water Systems. Throughout our coverage of this topic, we have introduced and re-introduced the concepts of “Curve Control” and “Area Control” as variable speed pumping control strategies, each time digging a little bit deeper. Today we are going to take an all-inclusive look at Curve Control, because we feel like the concept is often misunderstood .....Read More