Pump Size

newbie here.I think I just posted to the wrong place. Hope this is right...I will be having and 18x43x28 40,000 gal L shaped pool installed soon and was wondering if a 1 1/2 hp pump will be powerfull enough for that size pool.

What size of lines do you have (1.5" or 2") and what is the filter type/size. I expect the members with good operational knowledge will be be able to help better with specs.

I believe the rule of thumb is you want a pump that is big enough to turn over your water in about 6-8 hours through a big enough filter to do the job. If you are moving the water too quickly the filter can't do its job. You really don't want to small a filter.

There is some info here, http://www.poolsolutions.com/tips/tip83.html but it is mainly to forewarn over being sold to big a pump. The important point is to get the flow rate the pump gives through your size piping so that you can figure out about how long it takes to turn your pool water over.

There used to be a lot of info available through old posts but I think it was in the old forum info that got lost.

thanks for your help....I believe there will be 1.5" lines and the filter will be a hayward sand filter Pro Series model #S244T. I don't really know much more than that right now!:)

I am a firm believer in small pumps and large pipes. Unfortunately, many pool builders do the opposite. There are some exceptions. If you have a spa, water feature or pool cleaner that runs off the same pump as the filter, you may need a higher HP pump. I would then go with a 2 speed pump.

I would target an 8 hr turnover which is about 83 GPM. If you go with 1 1/2" plumbing, your head loss could be as high as 60 feet. With 2", which I highly recommend, it will probably be closer to 50 feet. So depending on the make of the pump, you could go with a full rated 1 HP pump.

agree with all you said, mas. first thing i was thinking when i read the pool size and idea of 1.5 inch lines is "go 2 inch lines'. i have about a 14-15,000 gallon pool so less than half the size (that's going to be a big ass pool!) with 1.5 inch and 3/4 hp (soon to be 1 hp) pump and 6 hours twice a day for turnover seems reasonable.i can't see turning over a pool your size with 1.5 inch lines without running the pump well more than half a day for a turnover!

Go with the 2" lines from the skimmers and main drain. If you intend to use solar panels in future, the 1½ HP pump should be adequate.

Pat

poolpup,

If I were constructing a 40k pool for you it would have a 1 1/2 hp (no spa) or a 2 1/2hp (spa) pump size.
I'd use 2" lines with 2 dedicated skimmers and a dedicated main drain, these pipes would come back to the equipment pad and be individually valved.
The filter would be either a 60sg/ft DE, 36" sand, or 500sq/ft or larger multi cartridge filter. The cleaner would be a booster pump assisted Polaris 280 or Pentair Legend.

See Ya,
Kelly