New Pump, desparatly need advice

[michaelwamsley]

My in laws need help and I am out of my comfort zone. Ask me anything you want about massive saltwater systems, filters, plumbing, and circulation systems, but unfortunately those skills have not transfer to small sized backyard pools

My mother-in-law has a 13,700 gallon pool with a spa of 350 gallons. It has been run by a Northstar 2hp pump (sp4015x20ns) for the past 4 years. This is the pump the company that installed the pool put on the system , it seems a bit large for the system (the company even throttled it back about 30% on the intake ball valve) but like I said I am far outside my area of expertise. The problem is that it has apparently been dry started numerous times and this pump is not a self priming pump. It was never quiet before, but now it is completely ruined and will no longer function at all. They need to replace this pump and I need your advice. I can do any type of re-plumbing and electrical work needed, but I do not know what kind of pump to replace it with.

Like I said their total water volume is right around 14,000 US gallons and I think it would be a good idea to have a self priming pump in this case. I do not really think it makes a difference, but the pump discharges through a very large micron filtration unit (capable of handling a pool of 48,000), then through a heater, and then back into the pool. It is a "saltwater" pool and for their sake I want to stay with one single speed pump. I would like it to be quieter, energy efficient, and durable than their previous pump was for them. They are on a fixed income, so price is somewhat important also. Is there any other information you need to help make a recommendation?

I have been looking at Pentair, Polaris, Sta-Rite, and Waterway. Which flow
rate would be best? Are these better than the Haywards? How would you rank them? Is there a good place to see comparisons on these pumps? They do not need top of the line just because it is the best, they need the best value for their system. If it were your pool, what brand and model would you go with?

Thanks in advanced for the help and if you ever need any help with closed aquatic marine ecosystems of any size, let me know!

Michael

 

[zea3]

Do you know how the pump came to be dry started? There may be an air leak that caused it to loose prime. a 3/4 or 1 hp pump should work for their set up. Personally I have been happy with the performance of my Pentair pump.

 

[Sparkmaster]

A little bit off your question but I was always told in my career never to restrict the flow to the pump but you can restrict it on the output.. Is that what Im reading from your post??

 

[geekgranny]

Welcome to TFP.

I'm curious. Is the "large micron filtration system" like an industrial filter for liquid purification and/or filtration? I'm familiar with a micron filter for spa use, that is discarded after a period of use rather than cleaned or washed. Or is it a standard type swimming pool filter; cartridge, sand filter, or DE filter?

You say "saltwater". Is this a saltwater (chlorine) generator, SWG, or truly saltwater?

I'll let the experts help you with your pump issue.

gg=alice

 

[michaelwamsley]

Zea3
The dry start was because they would clean the pre filters and turn off the pump and drain. From what I understand they would unscrew the plugs and drain the pump and lines entirly. I am not sure the reason, but they did not thin it was a problem b/c they thought it was self priming. They would also stop running their pumps and drain the lines in the winter (we already talked about this one) and again dry start it. When I came to town this spring they said it would run for 2 hours before it finally started pulling water!

Sparkmaster
your assessment is correct. I agree in my experience it is a cardinal sin to restrict the intake or discharge for any extended period of time. The pool company told them to do this. I even found a picture the company gave them to show how much the different valves should be restricted. They were restricting the only line in and out of the pump. I believe they were sold an oversized pump and this was the solution. My in laws said the pump would run so hot you could not touch it without being burned, but they thought this was the way it was suppose to be. I want to fix this issue for them.

Alice
There are four 1 micron cartridge "poly-filters" (what I use to pull toxins and heavy metals out of delicate invertebrate systems). The good thing is they keep the water very clean and do not need a lot of maintenance, the bad is they are VERY expensive to replace once every 2-3 years. Not too sure why this was done- like I said it is more massive aquarium displays than for a swimming pool. I know they have other filters also, but again this is out of my expertise. It is a chlorine generator pool, sorry I am not up on all the lingo- I usually just swim in the ocean

Thanks for the feedback so far. I hope this clarifys the details I left out. Please let me know if you néed additional information!

 

[zea3]

I'm amazed the pump has lasted this long! I think even with a self priming pump there has to be some water in there for it self prime.
Unfortunatley too often what the pool store sells you is not nessessarily what is best for the pool. I have not had issues so far with my oversized pump, but it was part of the standard package that was offered for my pool.

Again, I think a 3/4 to 1 hp pump should work fine. I am not familiar with the filter system you describe, so I don't know if it needs any more hp than that to work.

If you can add any pictures that would be helpful.