Open cooling tower pumps are traditionally operated as constant speed. When balanced, the extra pump head or over-heading is throttled across the discharge balance valve …
Variable Speed Pump Control – More Detailed Curve and Area Control
Curve control, Area control, Sensorless control, Remote DP sensor control. Local sensor control: the shopping cart of speed pump controls can get overwhelming. We just …
Hydronic Pump Energy: Motor & VFD Efficiency – How Low Can You Go?
I’m in the middle of the series of blogs on parallel pumping. We can’t ignore the efficiency of variable frequency drives and motors when looking …
HVAC Hydronic System Variable Speed Pump Operation
I am beginning a series on parallel staged variable speed (VS) pumps. As I write this series, it is important to understand and refer to …
HVAC Hydronic Pumps – Should I Trim the Impeller or Trim with Speed? (Part 2 of 2)
In the last R. L. Deppmann Monday Morning Minutes, I offered a couple of reasons why an engineer would schedule a larger impeller than needed …
HVAC Hydronic Pumps – Should I Trim the Impeller or Trim with Speed? (Part 1 of 2)
Engineers schedule a pump capacity in GPM and head along with the horsepower. The pump manufacturer traditionally trims the impeller from the maximum size, also …
Department of Energy Pump Standards [Part 5] – Your Choice of Variable Frequency Drive
My March 11th blog article concerning The Department of Energy Standards for centrifugal pumps raised questions about the engineer’s or owner’s choice of variable frequency …
Over-Speeding of B&G Variable Speed Pumps
I hope everyone had a wonderful Thanksgiving celebration. Here at Deppmann, we are thankful for the great industry we serve and the great people who …
Variable Speed Pump Area Control & System Diversity: Part 3
In the R. L. Deppmann Monday Morning Minutes part 1 of this series we defined diversity in hydronic systems. Part 2 introduced the sensorless pump speed …
HVAC Variable Speed Pump Curve Control: Part 2
The HVAC engineer or designer has many choices when it comes to the control of variable speed pumps. The traditional differential pressure (DP) transmitter near …