Ok. So the Tristar vsp sp3206vsp shows 1.85 hp. My North Star shows 2.0 hp. 1.35 SF. would the Tristar be ok? I’ve read/heard lower hp in newer models is equivalent to higher in older ones
True/false
The old Northstar pumps were, basically, too much pump for most applications. They had special motors with high service factors and moved tons of water. I actually had the Hayward engineers tell me that I should use a different pump on 3 different projects because of that, they would move too much water. There were other issues as well and Hayward discontinued them in favor of the TriStar, an excellent pump itself.
You don't give any information about your pool so just asking, "Will this pump work?" is difficult to answer, but a 2.7thp VSP will work on any pool. At first, the only readily available VSP were Pentair's original, and they had a total horsepower rating of 3.8 - 3.9 (every box had a slightly different label). You just turned them to slower speeds depending on application.
Brand new pumps are quiet. The W3SP3215EE pump you reference is a single-speed 1.5hp with a service factor of 1.5; 2.25thp (No longer legal in the US.). At 40ft. head (an average starting head on a pool system) that pump is going to try to move about 135gpm. Unless you have 2.5" or 3" plumbing your pipes (2", most likely), for pool purposes, should only have about 60gpm going through them at the most (7 ft. per second flow). If you slow the water down even more and run the pump (VSP, of course) longer you will get better results with your pool and great energy savings.
The single-speed pump will keep trying to push its rated amount, use and waste the energy because it can't, pressures will be high, and it could result in more noise than you are willing to accept.
