Balancing

Using a pump curve to estimate flow is a useful technique, but only if the gauge piping is correct. In this case, the gauge was connected upstream of the suction diffuser instead of at the pump flange, making the pump appear to be overflowing when it was actually close to spec.

A 15-storey apartment building with chronic cold complaints had most of its pump flow short-circuiting through an oversized, unbalanced unit heater in the penthouse mechanical room. Closing one ball valve brought immediate improvement — and a tenant confirmed the problem had existed for 22 years.