- Jul 8, 2011
- 41
JasonLion said:For a 13,300 gallon pool, using the common commercial pool requirement of three turnovers per day gives a desired pump flow rate of just under 28 GPM. Residential pools don't need anywhere near the flow rate required by commercial pools. In fact the flow rate requirement for a residential pool of 13,300 gallons is so low that other considerations, like being able to vacuum, become the dominant consideration, Any pump that will be able to vacuum the pool will provide more than enough water flow to satisfy the filtering requirements. At that point it becomes a question of getting the smallest pump you can that will still be able to prime, vacuum, and will work correctly with your filter, all of which are going to be at lower flow rates than your current 63 GPM target. Getting a pump larger than what you need will work, but it will use more electricity than you need to be using and provide no advantages.
Exactly. Since I am selecting for two speed, I am looking for the maximum that the pool is designed for at high speed. The 63GPM target is intended to get my half-speed at around the 28 GPM you mentioned, and I am basing that on the Kreepy Krawly manufacturer's statement that it's minimum operating requirement is 25-28 gpm. (They told me this on the phone.)
I'd love to be able to calculate the TDH at 1725 rpm. The Hydraulics 101 didn't establish how I would create a plumbing curve to do that and I have no idea as to how people are able to use the low-speed portions of the pump curve without it.
I think I could still get away with dropping it to a 3/4HP impeller in order to stop slamming my grids and breaking ribs during backflushes, too.mas985 said:The Pentair Challenger 346204 is a 1 HP up rated pump with a SF of 1.25 for a THP of 1.25. The motor I orignally suggested, A.O. Smith B2980, is a perfect fit for your existing impeller and would still allow you to save both energy and money.
but if you are selecting the new pump based on the point in the curve of your given TDH and expected GPM, you should get what you are looking for. Either that or my continuity of the conversation is getting very screwed up.mas985 said:But our discussion was about changing the pump size. And when you do that both the head loss and flow rate changes.