Intelliflo Vs Upgrade And Pool Filter Sizing

[sjpoolowner]

Hi all,

I have a 3/4 HP (3450 RPM) pool pump and 150 sq ft (max 56 GPM) cartridge filter for my pool (roughly 18000-20000 gallon, I think). They have been working well.

To further down the electricity cost, I was recommended to upgrade my pump to Pentair Intelliflo VS-3050 (3HP, max 174 GPM at 3450 RPM). Some questions here:

1. Will it really cut down the cost? Running a 3HP pump at a low RPM (like 1000?) vs a 0.75 HP pump at 3450 RPM? Intelliflo is supposed to use a more efficient motor than the one my current pump has, but how should I compare?

2. What is the minimum RPM I should run the Intelliflo at when I have solar panels on the rooftop (single story house)?

3. I was also told that I should get a bigger size of pool filter when I upgrade the pump. Is it necessary even if I only plan to run the pump at a low RPM? What will be a proper sizing for a cartridge filter?

I'm a novice in this area, so any help would be greatly appreciated.

Thanks!

[ps558]

Hi all,

I have a 3/4 HP (3450 RPM) pool pump and 150 sq ft (max 56 GPM) cartridge filter for my pool (roughly 18000-20000 gallon, I think). They have been working well.

To further down the electricity cost, I was recommended to upgrade my pump to Pentair Intelliflo VS-3050 (3HP, max 174 GPM at 3450 RPM). Some questions here:

1. Will it really cut down the cost? Running a 3HP pump at a low RPM (like 1000?) vs a 0.75 HP pump at 3450 RPM? Intelliflo is supposed to use a more efficient motor than the one my current pump has, but how should I compare?

2. What is the minimum RPM I should run the Intelliflo at when I have solar panels on the rooftop (single story house)?

3. I was also told that I should get a bigger size of pool filter when I upgrade the pump. Is it necessary even if I only plan to run the pump at a low RPM? What will be a proper sizing for a cartridge filter?

I'm a novice in this area, so any help would be greatly appreciated.

Thanks!

Before you go through all that. How long do you run the pump you have now? It the pool system ran by a auto controller? The reason I ask is you can reduce the run time of your current pump. If you have a pool controller system, you can buy a two speed pump. The last option is to buy a AO Smith Centerion motor which is more efficent motor than a standard pump motor.

[chem geek]

I can give you my own experience where switching from a 1 HP single-speed pool pump plus 3/4 HP booster pump (for the pressure-side cleaner) to an Intelliflo VF has cut down my annual pump electricity cost from $1400 to $700. Our marginal electricity rates are very high at around 32 cents per kilowatt-hour. Because we have 12 solar panels each needing 4 GPM for 80% efficiency, that 48 GPM is fairly high so the pump uses around 1500 Watts (@ 3000 RPM). The pipe runs across the roof for those panels are rather long and the runs to/from the roof are also long -- everything is 2" pipe (would have been better to use larger pipe from the pump to/from the roof, but they didn't and the Fafco headers are 2" so no choice for that portion). With my previous pump, I was at around 1800 Watts so not that much savings when the solar is on though it is a 17% reduction. When the solar is off, I can run at 26 GPM and the power usage is only 275 Watts (@ 1500 RPM) so a VERY significant savings of nearly 85%.

Note that a small drop in GPM results in a rather large drop in power. Roughly speaking, the power varies as the square of the GPM so cutting the GPM in half cuts the power by 1/4th. My example of solar on vs. off results in even more savings because there is far less pipe to go through in the solar off case (so less resistance/head). So if you wanted to sacrifice some solar heating efficiency you could do, for example, 3.5 GPM or 3 GPM per panel, with the latter at around 70% efficiency vs. 80% at 4 GPM so not that big a deal. Yet the savings is large since 3 GPM for 12 panels is 36 GPM and down from 1500 Watts to around 850-900 Watts. In my case, I can't usually do that since we use our pool as a therapy pool so keep it warm at 88F and need as much solar as we can get except for maybe a couple of months in peak summer when the solar is only on for 3-4 hours to reach desired temp. The solar is usually on 4-6 hours so the real savings comes from the 2-4 hours the solar is off. I suppose I could cut down the flow rate from June 15 through August 15, but I'd have to manually change that as my IntelliTouch system doesn't have a "flow rate by time of year" feature.

We also save by having replaced the booster pump. We still use the dedicated pressure line, but I use The Pool Cleaner pressure-side cleaner with the pump set for 15 GPM (@2180 RPM and 540 Watts) and run that on its own at night for a couple of hours. That works reasonably well for our pool.

Just note that the Pentair Intelliflo is not particularly efficient at the highest speeds. It really shines at the lower speeds so is far more efficient than the low speed of a 2-speed pump, for example. So your savings comes from those lower speeds and the ability to fine tune the higher speed to not be quite so high.

As for the cartridge filter, I don't know why you'd need to change that on the basis of changing the pump since it doesn't sound like you are going to be using it at any higher flow rate than you do today, but I will say that in general an oversized cartridge filter can be more convenient in not having to clean the filter as often. In my own pool, I only need to clean the filter once a year. Then again, it's a 4-cartridge monster (350 square feet for a 16,000 gallon pool) so is a PITA to clean. Some people prefer a smaller single cartridge filter they clean once a month or so. It's really a personal choice. The filter certainly does a great job cleaning and I'm happy with the results. You can see my pool here and here. The more extreme example of more frequent cleaning is either the sand filter you backwash weekly or the Desjoyaux pool bag you clean roughly every 10 days. The Desjoyaux pool has the pump right next to the pool so is most energy efficient and allows for fast turnovers, but I don't see how that works so well if you use a solar system where I'd expect the pump noise to be more like it is for a spa. Oh, that's something else about the Intelliflo -- it's a very quiet pump (obviously much quieter at slower speeds, but even at its highest speed it's quieter than my old pump).

Richard

[texasmax]

ChemGeek- so you're saying you're plumbed such that the Intelliflo circulates the pool during the day, and switches over (valve automation/etc) to push the cleaner at night, correct? Meaning you're never pushing the pool and the cleaner at the same time.

[Pool Clown]

1. Will it really cut down the cost? Without spewing a bunch of facts and figures, yes. (No offense Richard.) Running a 3HP pump at a low RPM (like 1000?) vs a 0.75 HP pump at 3450 RPM? Intelliflo is supposed to use a more efficient motor than the one my current pump has, but how should I compare? An easy way is to run your pump and note the pressure on the filter. Then install the new pump, and ramp it up to the same pressure and lock it in. Continue to run the pump that way with the same hours as your old one for one billing cycle (electricity). Compare your new bill with the one of the previous month. I realize this is a very barbaric way to compare, but it works for my customers. Of course its not precise, but it will give you a good idea.

2. What is the minimum RPM I should run the Intelliflo at when I have solar panels on the rooftop (single story house)? Usually with solar panels there will be a drain down valve that opens when there is a little vacuum on the panel to help drain the panel out when the pump turns off. Not enough flow/pressure to the panel will cause the valve to hang open, air will be drawn in to the system, and you will get a stream of bubbles at the return. Slowly ramp up the pump till you no longer get the bubbles then give the pump a tic more speed, to compensate for the filter getting dirty over time and lowering the flow rate. That should be enough flow for the solar.

Note: This is actually more of a jumping off point than a definite setting. All systems are different, and you will probably have to tweak the speeds a little to find what works best for your system.

3. I was also told that I should get a bigger size of pool filter when I upgrade the pump. Is it necessary even if I only plan to run the pump at a low RPM? What will be a proper sizing for a cartridge filter? The guy that is talking to you is probably working on commission, need i say more?

[chem geek]

ChemGeek- so you're saying you're plumbed such that the Intelliflo circulates the pool during the day, and switches over (valve automation/etc) to push the cleaner at night, correct? Meaning you're never pushing the pool and the cleaner at the same time.

Yes, you've got that exactly correct. When I got the Intelliflo, I had my PB put in a valve to switch between the regular (3) returns and the single dedicated line I already had which was used by the booster pump to drive a pressure-side cleaner. So I have my Intellitouch programmed to turn the valve and run the pump to The Pool Cleaner at night at a low 15 GPM. I pretty much have to run it at night because I can't force the solar to not come on during the day when the cleaner is on, or alternatively I can't force the flow rate to be low enough for the cleaner when the solar is on. The Intellitouch will use the highest flow rate when multiple programs are requested simultaneously; hence my running The Pool Cleaner at night when the solar can't come on.

Note that the Intelliflo cannot be used to drive a traditional pressure-side cleaner that expects a very high PSI pressure (up to 50 PSI) at low flow rate (11-14 GPM). The Pool Cleaner is designed to be used with a traditional return flow and normal pump so works well on a dedicated line at 15 GPM with the Intelliflo. It is not quite as good a cleaner as a regular pressure-side cleaner, but for my pool it works out well and it's less expensive to operate.

[sjpoolowner]

Wow, thanks a ton for all the replies. Helped me tremendously.

ps558, I've been running it for 3 hours/day during the winter season. Will increase it to 6-8 hours soon. We have Pentair Suntouch controller and the reason why I'm looking into Intelliflo VS-3050 is that the pump works with that controller.

I guess the reasoning behind replacing the filter as well as the pump is that that person thought my current filter (150 sq ft) is a bit smaller even for the current setting. It's been working quite all right with my current 0.75 HP pump, though. Maybe he was concerned that the filter is not big enough for the maximum flow rate that the VS-3050 can provide.

It is good to know that the current filter will likely survive with the new pump as long as I keep the flow to the same rate. I have Sta-rite system 2 filter and it looks like I can actually use 200 sq ft cartridge with the same tank that I have now if needed. Not sure how much increasing 50 sq ft can help but it sounds like a good option.

By the way, I have a Polaris 380 cleaner with a 0.75HP booster pump. Chem geek's info on using the intelliflo for pool sweep is interesting, but it sounds like I'll probably need to keep the booster pump with VS-3050.

Thanks again!

[chem geek]

By the way, I have a Polaris 380 cleaner with a 0.75HP booster pump. Chem geek's info on using the intelliflo for pool sweep is interesting, but it sounds like I'll probably need to keep the booster pump with VS-3050.

Yes, if you want to keep your Polaris 380 cleaner or use any other standard pressure-side cleaner, then you'll need to keep your booster pump. If you want to use the Intelliflo for cleaning and eliminate the booster pump, then you need to use a pool cleaner designed for lower pressure. The valve switching to the dedicated line works well though some people just have the cleaner hooked up to a regular return, but we didn't want the cleaner operating while we were in the pool and found that not having the cleaner line dedicated fully (i.e. trying to partially run the cleaner and have regular circulation at the same time) was unreliable and used a lot more energy. As for low pressure cleaner options, there is The Pool Cleaner, Pentair Kreepy Krauly Legend II, Polaris 360. Note that The Pool Cleaner uses around 7 PSI pressure at 15 GPM (total pressure is around 11 PSI including losses in the 1.5" dedicated line) while the Polaris 360 requires 17 PSI so will be less energy efficient (though may clean better).

[sjpoolowner]

Thanks, chem geek.

I actually have a question for you. You said your VF pump flow is 48GPM at 3000rpm, 1500 wats and 26GPM at 1500RPM, 275 watts. But for the pool sweep, the flow is 15GPM at 2180RPM, 540 watts. Why the lower flow at a higher rpm? Did you actually set at 2180RPM and got 15GPM for the sweep or vice versa?

I was also told that GPM is propotional to RPM. So in your case, the theoretical mximum GPM is 55.2GPM at 3450rpm (max rpm) due to plumbing resistance and other reasons, even though the documented maximum GPM for VF is 174GPM?

I also learned that my current controller will work with VF as well. Do you think it is worth spending more $$$ to get VF instead of VS-3050 for its flow control features? I heard the motor and everything else is same.

Again, thank you so much for the help!

[chem geek]

I set the flow rate and the pump adjusts the RPM to get to that flow rate. The reason for the lower flow at higher RPM when going to the pool sweep is that it is flowing through a single 1.5" line (as opposed to a 2" line that gets split into 3 regular pool returns) and the pool sweep has a lot of flow resistance. I've measured the pressure separately with the pool sweep off and figure that 4 psi is from the 1.5" line and outlet while 7 psi is from the pool sweep by itself -- the total being 11 psi (that's around 25 feet of head).

The GPM is only proportional to the RPM all else equal. You can easily make this relationship non-linear by having different flow resistance and your calculation of my maximum flow rate for my system is only correct when the solar is on. 55 GPM is probably the maximum achievable flow rate (at 3450 RPM) in that case. However, when the solar is off, there is far less resistance and my maximum flow rate (at 3450 RPM) is around 78 GPM. I should note that my solar runs are extraordinarily long -- having a long run from the pump to/from the house and an even longer run down the length of the house for the panels which zig and zag across various roof hips. I have 11 Fafco SunSaver and 1 Fafco Revolution panels.

As for whether the extra expense is worth it to get the VF and be able to set the flow rate, that's up to you, and you are right that the motor and everything else are the same. You could certainly buy a flow meter that you plumb in and then use the VS and experiment with different RPM to get the flow rate you want in different scenarios. You would then just program those RPM. The only real advantage to the VF is that it will automatically and dynamically adjust the RPM to achieve the flow rate so even if a filter starts to produce more resistance, the VF will maintain the same flow rate. In my case, that's not a big deal at all -- my cartridge filter even after a year without having to clean it doesn't rise in any noticeable pressure (maybe 1-2 psi at the most). I just went with the VF for convenience and because the extra money in the grand scheme of what it cost me with installation costs wasn't that much.

[sjpoolowner]

Ah.. all makes sense. Thanks again for your fast and detailed response!