Whisperflo Flow rate?

tcat

Well-known member
May 30, 2012
767
Austin, TX
#1
I've read a lot of threads and looked a bunch of tables... just confused. Trying to figure out flow rate on low speed (Whisperflo, AO Smith 1Hp 2 speed, 3450/1725), 48 sq. ft. Pentair DE filter (20psi/4psi), 2" pipes, 30-40' to pool, 1' above pool. Buying a 110BTU heat pump rated at 25-80gpm, optimal 50gpm. I know higher flow is better, but if my Low is 40 gpm or so, I'd rather run on low 12 hrs per day.

Also getting a 3gpd variable Stenner pump (pool takes 25-40 oz. chlorine per day), plan on injecting slowly over 6-8 hr day. Be nice to run everything on low from 8 AM to 8 PM. Will need to upgrade timer if heat pump won't work on low. Sorting out what I need to buy.
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
#2
Mark can probably calculate a flow rate guess for you if you also tell us your filter pressure gauge reading and how high the gauge is above the pump.

However, knowing the flow rate is essentially never important and hardly ever good for anything other than academic interest. The heater should certainly have it's minimum flow rate, and I can't think of anything else that would care about flow rate.

Also, it is exceedingly unlikely that you need to run the pump anywhere near 12 hours a day. The ideal pump run time is typically half of that, or less. See the article in Pool School on determining your ideal pump runtime.
 

tcat

Well-known member
May 30, 2012
767
Austin, TX
#3
Psi was given, gauge is about 2' above pump. Only reason I run 12 hours is surface stays a lot cleaner, but thanks for the mention since I forgot I can turn it way down since I started putting a cover on it now that it's 70 and will be much colder later this week. Just want to make sure it's at least 30 gpm.

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mas985

TFP Expert
LifeTime Supporter
May 3, 2007
12,126
Pleasanton, CA
#4
The 1 HP Whisperflo comes in two versions, up rated (WFDS-24) and full rated (WFDS-4). I estimate the high/low flow rate for the full rated at 74/37 GPM and 66/33 GPM for the up rated version.

But as Jason pointed out, flow rate is really irrelevant. What really matters if the skimmers still work well on low speed.
 

tcat

Well-known member
May 30, 2012
767
Austin, TX
#5
LOL. The built in skimmer barely works on high, my added Pool skim works great on low. My only concern is enough flow for the heat pump. I'll find out in real life. Thanks!

edit: Got a good rain last night and needed to drain some water. I times 1" drop at 5 minutes. With my approx. 380' surface I calculate about a 45 gpm flow on low. Will be less with the 48' DE filter in the mix. If it's 35-40 the heat pump should run fine on low. I have read it less efficient, but not "that" much less. Plan is to run HP only when pump is running, probably 8 hrs/day on low. Will run Stenner the middle 6 hrs of that.

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tcat

Well-known member
May 30, 2012
767
Austin, TX
#6
Update: I have Jandy valves set up now that will go to a future heat pump. I did a quick 5 gallon "dump" with times between 6.6 and 6.8 seconds. That's around 45 gpm on low! Good news, heat pump should have no issues on low. Also about a 6 hour circulation cycle, so I plan on running the pump on low 8 hrs per day.