How to Build a Centrifugal Pump Curve Part 2: Trimmed Impellers

How to Build a Centrifugal Pump Curve Part 2: Trimmed Impellers

In Part 1 of our Building a Pump Curve series, we discussed the parts of an unplotted pump curve. Now it's time to add some curves! In Figure 1, we've added a single head/capacity curve for a 9.5-inch diameter impeller--the largest impeller that can be used with our example pump, a Bell & Gossett e-1510 4BD. During laboratory tests...

Read More

Hydronic Balancing Part 7: When to Trim the Pump Impeller

Hydronic Balancing Part 7: When to Trim the Pump Impeller

Balancing isn’t just about adjusting valves. Sometimes (very often in fact) it is about evaluating the performance of the pump(s) under real world operating conditions. Remember what ASHRAE 90.1 has to say about Hydronic System Balancing: “Hydronic systems shall be proportionately balanced in a manner to first minimizethrottling losses; then the pump impeller shall be trimmed or pump speed shall be adjusted to meet...

Read More