We recently received an inquiry from an engineering firm deciding whether to change their pump schedule. They currently select the pumps at design capacity and …
Variable Speed Chilled Water Systems: Demand Reset
There are multiple methods to vary pump speed in HVAC chilled water systems. A common method is the use of a differential pressure transmitter at …
How to Limit the Speed of the Pump using a Danfoss Variable Frequency Drive
In this Service Tip of the Month, we demonstrate how to limit the speed of the pump using the Danfoss Variable Frequency Drive (VFD).
Create a New Variable Speed Pump Control Curve after Hydronic Balancing
This week, the R. L. Deppmann Monday Morning Minutes will explain how to show multiple speeds on a pump curve and how to determine what …
Hydronic Pump Balance using the Variable Speed Drive (VFD) with No Balance Valve on Pump
When there is no hydronic pump discharge balance valve, the variable frequency drive (VFD) is an important part of the balance procedure. How does the …
Hydronic Pump Balance using the Variable Speed Drive (VFD) with Assistance from a Triple Duty Valve
Most centrifugal pumps in heating and cooling systems have some oversizing in the head calculation. Once the HVAC hydronic system is proportionally balanced per ASHRAE …
Open Cooling Tower System Pumps – Balancing the Pump Using a Drive
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 …