My pool's main pump is dying, probably won't limp along for much longer. See here for details. I've determined my best option is to replace it.
I'm trying to learn as fast as I can, there is a lot that goes into selection! I've read Hydraulics 101 and I think I understand most of it.
Here is all of the information about my pool that I think is applicable.
27,000 sq feet (free form design, quickly slopes to 9 ft deep, estimate from previous pool owner, have not attempted to verify)
Filter Pressure is 5.0 to 6.0 PSI with a freshly cleaned filter. Currently 9.0 PSI, last cleaned in April, no backwash since then, almost time.
48 sq. ft. Nautilus D.E. Filter, maximum flow unknown, wore off data plate.
Pool has two skimmers and one main drain.
Polaris with Booster Pump.
Existing Pump: 1.5 HP, SF 1.30, 3450 RPM, 115 V 60 Hz, 18.4 Amps, See here for more.
No spa. No water features.
Here is my plumbing setup: (please omit comments on socks with sandals)
EDIT: Pipe sizes were wrong before, fixed now
Aside from it being energy inefficient, I've been very happy with my pool's overall performance. I typically only backwash twice year, with one cleaning in the winter/spring. I backwash when the pressure climbs to 15 PSI. Right now I am running the main pump for 9 hours a day, and that may be a little overkill. I run it less when it's cooler. The water stays very clean and clear.
Using the formulas in Hydraulics 101, I determined that my:
Return Dynamic Head = 2.31 * 5.0 + 3 = 14.55 feet
Suction Dynamic Head = 14.55 / 30 = 0.5 feet
Minimum Flow Rate = 27,000 gal / 8 hrs = 56 GPM
So Pump Head = 14.55 + 0.5 = 15 which seems extremely low... I know that my pool is older (built in eighties) and seems to be lower pressure than newer pools, but 15 feet of head is really low.
Please help with recommendations for a new pump. If I left out any important information, please let me know. I'd like to order a new pump before my current pump quits for good.