I recently replaced an aging Sta-rite 1 HP pump with an Intelliflo VSF. The VSF reports total head, electrical power usage and flow along with rpm and allows for a complete picture of system performance. It gives me an excuse to make an Excel spreadsheet for something other than honey-dos and Christmas gifts. I digress.
I took the opportunity to re-plumb to upsize the short 1.5" inlet with 2.5" els and 2" pipe. I also lengthened the suction inlet to 12". I was able to upsize the outlet and reduce bends. The only disappointment was leaving a 1" length of 1.5" pipe inside the suction side Jandy diverter valve.
It was interesting to qualify the energy saving benefits of the VS pump. The flow data makes it easy to select the ideal heat pump flow. I did end up with a few questions and hope that @mas985 or other pump experts would provide their thoughts on these questions:
1. With the large suction side plenum (and inlet basket labyrinth), is the recommended 5 X diameter straight section really helpful for impeller function?
2. I calculated efficiency (hydraulic power/electrical power) of .46 to .47 in the 2250 to 3000 rpm range for the VSF. The head at 50 gpm is 44 ft. Is that efficiency level expected for this pump?
3. What efficiency would you expect for the old Sta-Rite (PHK2RA6E-102L)?
4. What is the proper efficiency term for what I calculated? It seems like a combination of pump efficiency and motor efficiency.
I will appreciate any thoughts.
I took the opportunity to re-plumb to upsize the short 1.5" inlet with 2.5" els and 2" pipe. I also lengthened the suction inlet to 12". I was able to upsize the outlet and reduce bends. The only disappointment was leaving a 1" length of 1.5" pipe inside the suction side Jandy diverter valve.
It was interesting to qualify the energy saving benefits of the VS pump. The flow data makes it easy to select the ideal heat pump flow. I did end up with a few questions and hope that @mas985 or other pump experts would provide their thoughts on these questions:
1. With the large suction side plenum (and inlet basket labyrinth), is the recommended 5 X diameter straight section really helpful for impeller function?
2. I calculated efficiency (hydraulic power/electrical power) of .46 to .47 in the 2250 to 3000 rpm range for the VSF. The head at 50 gpm is 44 ft. Is that efficiency level expected for this pump?
3. What efficiency would you expect for the old Sta-Rite (PHK2RA6E-102L)?
4. What is the proper efficiency term for what I calculated? It seems like a combination of pump efficiency and motor efficiency.
I will appreciate any thoughts.
