Hi everyone-
So my pump recently quit. It's a single speed, pretty loud Pentair pump, so I'm interested in replacing it due to noise and no longer functioning. I've been reading (and reading and reading), and I'm having trouble figuring out which pump/pumps would fit my needs. Here's what I've come up with so far:
1. the prior pump, which was 1.5HP single speed, may not be properly sized for my pool.
2. Pool builders/pool store tend to oversize the pumps which increases initial cost, monthly power cost, and may damage my system if run at too high of a GPM.
3. I had been looking at "turnover" to start my calculations, but this is "not the TFP way." The pump needs to run just enough to skim the surface and mix in the pool chemicals I add, as well as filter out the (nearly nonexistent) things that fall into the pool.
So now I have no idea how to figure out the size of the pump needed. I've read "Hydraulics 101", but I'm still struggling.
I can get out a tape measure and estimate the "total dynamic head" of the system using "Hydraulics 101" information. But how do I determine the GPM need?
Using the standard methods I found on the internet (the "turnover" method), I have:
-------------------------------------------------------
pipe size PVC 1 1/2" internal diameter
pool size 15k gal
2 to 3 turnovers per day seems to be the recommended minimum. Our pool isn't
used very much, so will go with 2 turnovers with plan to increase as needed
when needed then resume 2 turnovers per day.
assume 2 turnovers per day = 12 hr/turnover
15000/12 = 1250 GPH = 20.83 GPM or "'about" 21 GPM
maximum flow rate of 1.5" PVC piping is 42 GPM
maximum plumbing flow rate (3 intakes, 2 of which are active and the vacuum
line is unused due to robot vacuum) = 42+42 = 84 GPM
DE Filter is Hayward DE3620 = 36 sq ft of filter
Maximum filter flow rate = 54-72 GPM (Hayward manual lists 72GPM)
So my GPM range is 21-42 GPM?
----------------------------------------------------
However, when I go to pool parts stores, all these calculations may be completely irrelevant. I can filter down based on other essential criteria, such as voltage (I'm setup for 230v), "residential" as type of pool pump, and "variable speed" which greatly reduces the selection. The lowest HP pumps I can find are 1.5HP anyway.
So am I just wasting time? Just buy any 1.5 HP variable speed pump that matches my 1 1/2" PVC piping and be done with it?
Thank you so much for helping... I continue to be confused.
So my pump recently quit. It's a single speed, pretty loud Pentair pump, so I'm interested in replacing it due to noise and no longer functioning. I've been reading (and reading and reading), and I'm having trouble figuring out which pump/pumps would fit my needs. Here's what I've come up with so far:
1. the prior pump, which was 1.5HP single speed, may not be properly sized for my pool.
2. Pool builders/pool store tend to oversize the pumps which increases initial cost, monthly power cost, and may damage my system if run at too high of a GPM.
3. I had been looking at "turnover" to start my calculations, but this is "not the TFP way." The pump needs to run just enough to skim the surface and mix in the pool chemicals I add, as well as filter out the (nearly nonexistent) things that fall into the pool.
So now I have no idea how to figure out the size of the pump needed. I've read "Hydraulics 101", but I'm still struggling.
I can get out a tape measure and estimate the "total dynamic head" of the system using "Hydraulics 101" information. But how do I determine the GPM need?
Using the standard methods I found on the internet (the "turnover" method), I have:
-------------------------------------------------------
pipe size PVC 1 1/2" internal diameter
pool size 15k gal
2 to 3 turnovers per day seems to be the recommended minimum. Our pool isn't
used very much, so will go with 2 turnovers with plan to increase as needed
when needed then resume 2 turnovers per day.
assume 2 turnovers per day = 12 hr/turnover
15000/12 = 1250 GPH = 20.83 GPM or "'about" 21 GPM
maximum flow rate of 1.5" PVC piping is 42 GPM
maximum plumbing flow rate (3 intakes, 2 of which are active and the vacuum
line is unused due to robot vacuum) = 42+42 = 84 GPM
DE Filter is Hayward DE3620 = 36 sq ft of filter
Maximum filter flow rate = 54-72 GPM (Hayward manual lists 72GPM)
So my GPM range is 21-42 GPM?
----------------------------------------------------
However, when I go to pool parts stores, all these calculations may be completely irrelevant. I can filter down based on other essential criteria, such as voltage (I'm setup for 230v), "residential" as type of pool pump, and "variable speed" which greatly reduces the selection. The lowest HP pumps I can find are 1.5HP anyway.
So am I just wasting time? Just buy any 1.5 HP variable speed pump that matches my 1 1/2" PVC piping and be done with it?
Thank you so much for helping... I continue to be confused.
