Replace Jacuzzi Magnum 1000 1hp with Jacuzzi Magnum Force 1hp or Pentair Whisperflo 1

Hello everyone. I just joined the TFP forum and am hoping to get some help choosing the right new pump as I've seen posts from mas985 and others helping with this in the past. The casing on the pump has a hairline crack which I've siliconed for the last 2 seasons and its time to replace the pump.

My current pump is a Jacuzzi Magnum 1000 (1 MAG-U-S) 1 hp (motor replaced about 6 yrs. ago with new AO Smith 1 hp Motor, Model C48L2DB11. 115/230 volts, 12.4/6.2 amps, Max load 16.2/8.1, 1 hp SF 1.4, 3450 RPM). The pump has internal threads to accept 2 inch threaded fittings. It is currently wired for 110 volt via a cable with a three pronged plug which plugs into a standard 110 volt wall receptacle that is switched to turn the pump on and off.

I would prefer to do as little re-plumbing as possible and am therefore considering 2 pumps that have the same profile and height of the fittings so I can just transfer the threaded plumbing fittings from my Jacuzzi MAG 1000 to the new pump, and reconnect unions to reconnect the pump. I would prefer the pump to be quieter and run cooler than my existing pump, and additional energy efficiency would be a bonus. I would also like to stay with the pump wired as 110 volt as re-wiring to 230 volt would likely be quite expensive and difficult given the distance of the pump from the breaker box in our home. The two pumps I'm considering that I can obtain locally and be wired 110 volt are the Jacuzzi Magnum Force 1 hp, and the Pentair Whisperflo 1 hp. I could also order a Jacuzzi Magnum on-line (looks to be pretty much the same pump as Magnum 1000).

Here are some answers to questions from a previous posting to assist in correctly sizing the pump:
1. Why do you want a 1 HP and how did you size the pump?
Our existing pump is 1 hp. I went through the sizing protocol for Hayward pumps and came up with a 1 hp pump. Our pool is 18 ft x 38 ft oval, approx 3 ft shallow end and 8 foot deep end when full, avg depth 5.5 feet, approximate volume = 38 x 18 x 5.5 x 7.5 = 28,215 gallons. Gallon Per Hour flow required = 28,215/8 = 3526.875. Gallon Per Minute flow required 3526.875/60 = 58.78125 Gallons Per Minute. Average feet of head = 30.33 (closer return/jet 17 ft. from pump, skimmer 27 ft. from pump, further return/jet 47 ft. from pump, Avg ft. of head = 17 + 27 + 47/3 = 30.33) 1 hp pump arrived at to meet 58.7 gpm flow rate and ft. of head between avg ft. of head of 30.33 and longest ft. of head of 47 ft.
2. What is your current pump model and filter pressure?
Current pump Jacuzzi Magnum 1000 1hp. Filter pressure I'm not sure. The meter on the cartridge filter often registers at 10-12 psi.
3. What is the pump elevation relative to the water level?
Pump is at approximately the same height as the water.
4. What is the maximum recommended flow rate of your filter?
Filter is a Starite System3 S7M120 cartridge filter, max flow rate 100 gpm, max work pressure 50 psi, 300 sq. ft. filtration, filtration rate 0.33 GPM/sq. ft.
5. Do you have any water features, spa jets, floor cleaners, suction/pressure cleaner?
We have a Kreepy Crauly, and use a vacuum head to the skimmer to also manually vacuum the pool.
6. What is the diameter of your suction and return lines and how many do you have going from pool to pump?
Pool lines from the skimmer to the pump, and the pump to two returns/jets are all 1.5 inch diameter. The skimmer (Jacuzzi skimmer) has 2 holes in it, one connected to a main drain in the deep end of the pool, a second which is the return suction line to the pump. While there is a line from the main drain to the skimmer, it is not directly connected to the pump - water from the main drain only passively finds its way back to the pump via the other main suction line in the skimmer directly connected to the pump. The skimmer and return jets are all on the same side of the pool.
7. What is the distance of your plumbing runs pool to pump?
Closest run is from pump to first return/jet in the pool (17 feet). Next longest run is from skimmer to pump (27 feet). Longest run to second return/jet in into pool (47 feet). Flow of water: 27 feet from skimmer to pump, from pump through StaRite System3 Filter, from StaRite filter through Teledyne Laars Series 2 ESG 250 natural gas heater, to Hayward chlorinator, which then divides to the 2 returns/jets to the pool (closer return/jet 17 feet, further return/jet 47 feet).

We have been considering adding solar heating and/or a UV sterilizing system to the pool equipment, and would also like the pump to be adequate to handle the additional flow through the solar heating panels if/when we might add solar heat. The panels would be on the roof of our house (bungalow) 8-10 feet elevated from current location of the pump.

I understand the Whisperflo is quieter, runs cooler, draws less energy, and moves a higher volume of water. I’m strongly considering the Whisperflo, yet I’m concerned from previous posts I’ve seen about whether it is oversized relative to its flow output with our 1.5 inch piping and existing equipment. I'm confused about specs I've seen of the max flow rate for 1.5 inch pipe from 42 – 60 gallons per minute. I’m also concerned about the potential impact of the volume of flow from the Whisperflo upon our existing older Teledyne Laars furnace.

I’d appreciate your perspectives about how to proceed.
 
Both of those pumps are big for their labels. So they tend to deliver high flow rates at high energy use.

Also, I don't think the Whisperflo is any quieter than any other pump. Most new pumps will be quiet and the reason most old pumps are noisy are due to bad bearings. Also, lower flows rates means a quieter pump so I would recommend a two speed pump. The problem is that there a few two speed pumps that run at 115v so options are limited. Here is a good one:

http://www.sunplay.com/Pentair-SuperFlo-Pump-341111-p/341111.htm

BTW, head loss is not equal to the average length of pipe. It is a much more complicated calculation and is dependent on the fittings, filter, heater in addition to the length of pipe plus the flow rate going through the pipe. In fact, the length of pipe is lowest contributor of head loss.
 
I believe most contain the switch but not all. Check with the store first before ordering because some give the option.

Sometimes the SuperFlo 3/4 HP is hard to find and they may not have it in stock so the Whisperflo WFDS-24 or WFDS-3 would be an ok second choice.
 
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