VS Pump speed

KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Hello, very new pool owner here.

My PB setup my IntelliCenter with a single schedule that runs my VS pump at 40GPM 24/7. The equipment pad is around the side of my house but it is till pretty noisy, especially at night as it's under our bedroom window.

I'm wondering if I can/should run it at a lower GPM throughout the day and very low at night. As I understand, my SWG requires at least 25GPM to operate - can I set it to that at night?

Also, reading other posts here, I see many users referring to RPM vs GPM for their pump. Should I consider configuring it's RPM instead?

Thanks!
 

DeanP66

Well-known member
Mar 26, 2014
1,202
San Jose, CA
Kevin, unless you're running water features, or vacuuming where you require good suction, you can run your VSP at a lower RPM. With a SWG, you just have to run it fast enough so the flow switch closes on the SWG. I run my VSP at around 1100 rpm 24/7 with no issues. My SWG is always on as well, but I have the chlorine output set way down at 15 or 20%. When the heat starts to pick up in the middle of summer, I bump it up to 25 or 30% and I'm good.
 
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KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Whoa, my RPM is sitting at 2700 to get 40GPM. Any thoughts as to why my PB would have set it so high?
 

needsajet

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I can't advise anything about setting the intellicenter, but there's no reason to run it 24 hrs per day. If it was mine, I'd start with around 8 hours per day and the SWCG turned up to 90% until I detected that free chlorine (FC) was getting higher than needed, then ease it down accordingly.

If the pool is getting regular heavy use, it's possible you may need more running time, but I'd test my FC regularly so I'd see that coming. You can also keep a little liquid chlorine on hand for heavy swimming days, and add a litre or two before or after a big session. Listing the size of intellichlor in your signature would help with getting a sense of how much chlorine per day your system is producing.

As far as flow rate, the low end limit is whatever it takes for the SWCG to operate, including times when skimmers and filter are at the limit of how dirty you let them get, and however clean you like the water to look. For me, it's usually skimming needs that determines the RPM or flow rate I need. To increase skimming, you can throttle back the valve(s) to your main drains so they're only pulling a very small amount of water.

Nice to meet you via TFP! :)
 
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needsajet

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I just realised the word header in your signature is probably meant to be heater. You could need higher pump running time for heating, especially if that's a heat pump. There will be also be a minimum flow rate to get the most from the heater.
 

KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Thanks, I've updated my signature (I'm going to add the model # details later). It's a MasterTemp natural gas heater.
 

Newdude

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TFP Guide
Jun 16, 2019
7,826
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Hey Kev and Welcome !!!

Also, reading other posts here, I see many users referring to RPM vs GPM for their pump. Should I consider configuring it's RPM instead?
You can if you’d like us to easily understand you. The same goes for your Liters and Grams. :ROFLMAO:
Whoa, my RPM is sitting at 2700 to get 40GPM. Any thoughts as to why my PB would have set it so high
Yes. Because the PB could care less about paying your electric bill. But you see how quick you realized what 2700 RPMs meant ? It’s probably the best way to talk from here on out.

Mine activated my SWG and heater at 1100 RPMs. I ran it at 1200 to account for flow loss with a dirty filter. It skimmer fine for me and cost about $20 a month.

Start low and increase the RPMs until the SWG kicks on. Then see if the heater does too. If not you’ll need a 2nd speed when you want to heat. Add 100 RPMs to both minimum #s as your start point. If the pool skims ok you are done. If not try another 100 RPMs until it does.
 

needsajet

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Jim has the intellicenter experience, so I'll defer on the flow rate vs. RPM stuff.

It sounds like a setting that needs tweaking because your pump and overall setup should be moving something closer to 60 gpm at 2700 RPM. I'm assuming the pump is the 1.5 HP model.
 

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KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
You can if you’d like us to easily understand you. The same goes for your Liters and Grams
Aren't RPM and GPM different measurements entirely? Maybe I'm misunderstanding but I thought RPM was pump rotations/minute and GPM was gallons per minute going through the pump. I see that maintaining 40 GPM, the RPM goes up as the filter gets dirty. I assumed if I switched to RPM, the GPM would go down as the filter gets dirty.

It sounds like a setting that needs tweaking because your pump and overall setup should be moving something closer to 60 gpm at 2700 RPM.
Hmm, the equipment is ~20 feet from the pool and probably ~6 feet higher elevation. Could that account for the lower gpm at 2700 RPM?
 

KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
The same goes for your Liters and Grams.
Side question, when converting Liters to Gallons for pool related calculations, I should be converting Liters to US Liquid gallons and not Imperial gallons, correct? (Google calculator had both and I was confused)
 
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needsajet

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US gallons. Pretty much everything related to plumbing, pools and irrigation related is done in US gallons, even in Canada, Aus and UK. So when you see gallons, assume US gallons rather than the larger imperial gallon. It goes all the way back to early US merchants wanting to make more profit on a pint of beer.

I'm not a fan of pumps controlled by flow rate, just to be transparent about bias. It does matter for complex pools with intricate water features, but normally it doesn't matter if the flow rate varies some, it's just not a material difference. Yes, you're correct. As filter gets dirty, flow rate reduces if RPM is kept constant.

I have a flow gauge on mine, and right after backwashing, on the default medium speed setting (2400 RPM) of a 1.2 HP VS pump, I get around 160 litres per minute (42 GPM). By the time the filter is dirty, that's dropped down to around 140 litres per minute (37 GPM). From just watching the pool, no difference can be detected.

For your size pool, and two skimmers, I'd start with something around 1500 RPM and then tweak from there over the course of the summer to see what you like. It will depend on the valve settings for drains and skimmers. Assuming the drain has it's own valve, and each skimmer has a dedicated valve, you can also tweak those to help give you what you want.

Just a quick question, by "two drains" do you mean two intakes around 4 or 5 feet apart? Those may be on the same pipe back to the pad. Two intakes provide a safety feature that avoids anyone getting caught by them (sucked down and held under water). It's actually just a single drain, with correct, normal and safe dual intakes, far enough apart that if someone puts their hand over one or settles over it, the pump pulls water from the other and not enough force is exerted to hold them down.
 

needsajet

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Hmm, the equipment is ~20 feet from the pool and probably ~6 feet higher elevation. Could that account for the lower gpm at 2700 RPM?
No, once the pipes are full of water, the elevation makes no difference. There's an equal force pulling the water back down after the pump, to the force needed to lift the water up. Elevation only makes a difference during priming, and goes away once that's complete. The distance from pool to equipment is well within the normal range.
 

Newdude

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Jun 16, 2019
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Aren't RPM and GPM different measurements entirely?
They are and you are correct. But they both correlate that xxxx rpm equals yy gpm for your pool. (It's varies slightly from the filter, but close enough most times) Every pool /configuration will be slightly different, but they are close enough that we have the same understanding if we both run 800 rpm, or 3450 rpm. 2200 just means something to me if you mention it. 27gpm doesn't. Lol. Our pumps down here all came setup displaying RPMs and 99% of us never cared to change it.

You are welcome to use whichever you want to discuss of course. :)
 
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KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Thank you so much for all this information. I'm learning a lot!

I'm assuming the pump is the 1.5 HP model.
I believe it is 3HP.

Just a quick question, by "two drains" do you mean two intakes around 4 or 5 feet apart?
Yes, sorry, that's what I mean. I guess I should say 1 drain? I have one valve for each skimmer and another for the drain. For returns, I have one valve for the "pool jets" and one for each stairs.

For your size pool, and two skimmers, I'd start with something around 1500 RPM and then tweak from there
I did some testing to what RPM gets me what GPM (all valves fully open):
  • 1500 RPM ~= 5 GPM (SWG not running)
  • 1900 RPM ~= 15 GPM (seems the be the min to active the SWG)
  • 2200 RPM ~= 25 GPM
  • 2600 RPM ~= 33 GPM
  • 2900 RPM ~= 40 GPM
Do you still think something is wrong/mis-configured?
 

KevinBond

Well-known member
May 7, 2021
100
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
This is another thing that I keep noticing, when trying to maintain a specific GPM, the RPM continuously climbs. Since I jotted down the above stats (1.5 hours ago), 25 GPM is now 2660 RPM (up 400+)... Why would it be doing this?
 

needsajet

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OK, so you have valves on the returns to the pool, that's good to know. Also, you can control where the water is drawn from the pool.

It makes me wonder if the flow is restricted, which would reduce how much water a given RPM can move. How bout doing that same test with all the valves wide open so we know there are no restrictions? Perhaps also backwash the filter if that hasn't been done recently.

We need an intellicenter expert on this thread, something I'm definitely not, haha! Could someone pipe in and tell us how the intellicenter senses the rate of flow? Also, I'm recalling that many here have reported that operating the pump on variable flow rather than variable speed hasn't been hugely successful, but I've been out of the loop for a while - maybe they're getting better?
 

DeanP66

Well-known member
Mar 26, 2014
1,202
San Jose, CA
Kevin,
That is very strange. Your GPM's seem very low. I have a Flo Vis flow meter on my setup and I get 20 GPM at 1000rpm, 30 GPM at 1500 rpm and I only have a 1.5 HP VSP pump. I agree with needsajet above, something has to be restricting the flow.
 

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