The last three articles outlined pump selection in domestic water recirculation systems. In general, these systems have low flow and low head pumps. What happens in a high rise with pressure reducing valves (PRV) in the hot water supply? The pressure reducing valve introduces a fixed pressure drop which must be added to the calculations.
The purpose of the domestic water recirculation system is to delivery hot water near a fixture during times when there is no draw. If someone is using hot water in the next room or apartment or process; the hot water is near enough to your fixture so the hot water is delivered in seconds, not minutes.
The last two weeks we used the Pump Affinity Laws and the Xylem Bell and Gossett System Syzer® to either trim the impeller or reduce …
Last week we used the Pump Affinity Laws to determine what size the impeller would be trimmed to in an oversized pump. Reducing the speed …
The Pump Affinity Laws are used to determine the system curve. If we know the point of operation on a pump curve, we can determine …
Hydronic heating system flow rates and pressure drops are related through a series of AFFINITY LAWS. Let’s examine the laws and how to use them …
As a representative for Danfoss VLT variable frequency drives (VFD), we often are asked about the use of the VFD when single-phase power is the only …
In this Monday Morning Minute, we demonstrate how to limit the speed of the pump using the Danfoss Variable Frequency Drive (VFD).
Over the last few weeks the Monday Morning Minutes posts have looked at pumping issues with multiple condensers and pumps. One of our most-received questions …
Chilled water condensers are normally operated as constant-flow devices and the pumps serving them are constant-speed. Why would you ever use a variable-speed drive for …