wwodberg,
Floor cleaning systems require larger pumps(greater flow) to operate the heads than a pool with just wall returns.
You might think about using wall returns for the low flow filtration and the floor jets for the high flow cleaning. The intellitouch allows for easy programing of this feature. The VF works well with the infloor because it has the ability to adjust flow as the water valve moves to each series of heads when the floor cleaner is on. Generally, the heads will require about 25 gpm/head to operate efficiently.
Cleaning time will vary based on the size of the pool and number of heads(floor jets). Obviously, small pools running 2 heads per port are more efficient and reqiure less cleaning time than a large pool that requires 4-5 heads per port. Good luck.

I understand that in-floor systems require higher flow. One question I have though is if I run the pump at 30-40 GPM what will happen. I'm assuming that there would not be enough pressure to effectively clean the pool, but would water still be circulating in the pool?

What I'd like to do is run the pump at 100GPM for a few hours for cleaning and them return it to 30-40 GPM for the rest of the filter time. I understand that the cleaning cycle will require more power, but since I'd only be using that speed for part of the day, I would still get the benefit of the VF for the rest of the day.

I'm assuming at 30-40 GPM, the filtered water returning to the pool has to go somewhere, and it would still come out of the in-floor system. Does that make sense?

It will probably still come out of the infloor heads but the head loss will still be higher than normal returns and flow rates lower. Also, your skimmers may not work as well without surface returns.

woodberg,
You are correct to assume that the filtered water has to go somewhere. It will go thru the water valve and the heads. It's not a very effective way to circulate. That is why I suggested("You might think about using wall returns for the low flow filtration and the floor jets for the high flow cleaning. The intellitouch allows for easy programing of this feature.")you install surface returns to operate when you use the low speed to filter. Good luck.

woodberg-

Good question on floor system efficiency and power consumption. I have a floor system and a 2 speed pump. For cleaning, I only run the floor system at high speed for 1 hr and 40 minutes/day (1 complete revolution of each head in the system each day). During the summer, I only run it for 1 hr and 40 min every other day. This has kept my pool floor clean throughout the year. Running the floor system more than 1 head revolution per day at high speed is just re-cleaning areas that have already been cleaned and wasting energy.

Regarding efficiency at low speed, keep in mind that at low speed (30-50 gpm) the pipe frictional losses and nozzle losses are small and the floor cleaning system is pretty efficient at just circulating water (my filter pressure is 4 psi during low speed with all flow going to the floor system with no by-passes).

Like mas985 indicated, the higher speeds for longer periods of time is only required for skimming action so this will depend on how much surface debris you expect. In my case, I have a negative edge which catches most of the surface debris so I don't have much concern about skimming action through the skimmer. If you are looking for a skimmer that will work effectively at lower speeds, the venturi skimmers are reported to do well with lower speeds and save energy as a result. google "venturi pool skimmer" for more info.

Keep the pipe sizes big, keep the pump speed low and the floor system will be efficient at delivering clean and chlorinated water to your pool. Efficiency drops off with higher pump speed, but that is true of any filter circuit regardless of floor system or not. Longer high speed run times will only be required for effective skimming and this is where venturi skimmers will help. High pump speed should only be used for cleaning cycles, which are not that long each day.

Also, I see you are debating VS vs. VF for your floor system. There are reports on this forum of the VS being better for floor systems. The VF will get confused by the constantly changing load in the floor system when switching from zone to zone. Others on this forum, such as "deeker" or "product manager" may be able to help with your decision here or offer a way to "trick" the VF into working OK with a floor system.

Hope this helps!

Trhought, that's good practical info. You didn't explicitly say so, but I'm assuming you don't have any regular wall return's on your pool. Do you just circulate the water at low speed through the in floor system? Also, what in-floor system do you have.

I'm also surprised that it takes 1 hr and 40 minutes to run through I set of cleaning. How many zones do you have? My understanding is that each head would operate for approximately 1 minute. Maybe I'm not understanding your setup. Also, how many sq feet is you pool. The pool I'm considering would be about 700sq ft.

Golfgeek, I understand the point of you saying to plumb both wall returns and the in floor system, but I'd rather not do that if I don't have too.

woodberg-

Good question regarding wall returns. Yes, I have 2 wall returns located opposite the skimmer. These wall returns are on a valve that opens when the pump switches to high speed to help with skimming action. The valve closes when switching to low speed to send all flow to the floor system.

I have a Paramount PV3 system with 6 zones and our pool is about 700 sq.ft. also. May want to find out from Polaris what their cycle time is from zone to zone as well as head index degrees per cycle then calculate minimum high speed run time to get full head revolution for all zones using this info.

Hope this helps!

trhought, that is opposite of how I would have guessed you ran your pool. You're saying that when you are running at low speed, you are only sending water to the in-floor system for circulation. Then, for 1 hour 40 minutes you are running at high speed which also opens a valve and sends water to the 2 wall returns. Is that right?

I'm starting to realize that even with an efficient pump, the cleaning cycle is where the inefficiency exists. Using your data, if I run the in-floor system for 1 hour 40 minutes, I use about the same KWH as running the Intelliflo at 35GPM for the next 11 hours. I guess there is really no way around this. It seems like the best cleaning options are the in-floor system or a Polaris type cleaner with a booster pump. With that option the booster pmup is using power.

woodberg-

Yes. Low speed flow only goes to the floor system on our pool. High speed provides the high nozzle velocity at the heads that push the debris to the next zone or the main drain. During high speed, the valve also opens to divert some of the high flow to the wall returns to help with surface skimming action, although our negative edge does most of the skimming.

You are correct. The high speed causes high pump head pressure which raises the power consumed considerably. The less time spent on high speed, the less power consumed. I think the venturi skimmers for non-negative edge pools are a good idea because of their effectiveness at low speeds.

Regarding total power consumed when comparing variable speed vs. 2 speed, there are differences between the technologies. From field test data posted on this forum from Pentair, the efficiency favors variable speed technology due to the permanent magnet motor design, especially at low speed operation. The choice of one technology over the other is a personal decision depending on your needs.

Hope this helps!