Pump Size

[Knucklehead]

I think I was about to over buy a pool pump. I have a 35,000 Gallon Pool.
1. The pipes (put in 60 years ago) are all 1.5". I have 2 skimmers withe 1.5" pipe that I had coming into my pump that has 2" in and out. I am using 1.5" pipe to my sand filter and then to the inlet to the pool. I think the 1.5" inlet to the pool is my limitation. It's actually 1.5" to two inlets, but the 1.5" is buried and will be difficult to change anytime soon.
2. I just purchase a CircuPool RJ60 that I intend to install after my Sand Filter.
3. My Pentair Intelliflo Pump needs to be replaced. Not because of the pump, but the controller has become inoperable. I was going to replace it, but seems like it isn't too much more just to replace the 10 year old pump. I believe the pump I have is 3 hp. But after reading it sounds like my pump is oversized due to the limitations caused by my pipes. I've read some of the postings about pump sizing and I believe I should purchase a 1HP variable speed pump. Can someone help me out with this? My old pump seemed to do a great job, but I may have been wasting electricity and pushing my system and the pump harder than necessary.

 

[mknauss]

A VS pump is variable HP. So it is never oversized. You just run at the RPM needed to perform the job you need done. I would suggest replacing with another Intelliflo.

 

[Dirk]

What Marty said. One caution. You can dial down your IntelliFlo pump to any HP/RPM you need. Certainly low enough to protect your "vintage" plumbing. But when an IntelliFlo first starts up, it goes into priming mode. It runs at high RPM, for about 30 seconds, to draw water from the pool even if the pipe has no water in it. This priming mode creates a very strong suction that might be unkind to 60-year-old 1.5" pipes. But the priming mode RPM is adjustable, too, through the pump's interface, so you can turn it down. You might want to lower the factory-set priming mode RPM a bit, to take it easy on your pipes.

 

[Knucklehead]

I think the plumbing, although vintage in design, is more robust that physically 60 year old plumbing. We have replaced just about all of it over the years. I think there may be one galvanized section left under my concrete slab. The rest is all PVC mostly replaced in the past 10 years. The skimmers are concrete and vintage. Perhaps I should gradually replaced the plumbing with 2" where I can with the goal of having all of the plumbing 2" eventually.