Quick followup: It seems like what we want is to always run the pumps at the lowest speed possible that will get the water to the roof. Then we can run the pumps longer (for the same or lower cost) to optimize the heating. The exception might be to run faster during the time the cleaner runs.

But again, this has to happen by itself without us here.

Part of the problem using a VS pump with solar is setting it up properly to work with the solar design. Without solar, you will probably want a fairly low flow rate to maximize energy efficiency. When the pump first transitions to solar, it will need to be programmed for a higher flow rate to prime the panels. After priming, it may possible to drop the flow rate depending on where the vacuum release valve is installed or if you even have one. The valve needs to have positive pressure to stay closed and given the height of a two story building, the filter pressure will need to be at least 12-15 PSI if the valve is installed on the roof. This will require flow rates in the range of 40-60 GPM which is not the best efficiency for a VS pump. However, given that solar is more efficient at these flow rates, you may not want to drop the flow rate too much anyway in order get the maximum heat gain possible.

The bottom line is that you can get a VS pump to work but it may take a bit of optimization to get to the ideal speeds and flow.

I was told that the problem with the VF and solar is that the VF controller is always adjusting the pump speed to match the set flow rate. It is thought that when using solar, the water flow/pressure can vary often/quickly (the same issue with in-floor cleaners), which can cause problems with the VF controller when it tries to adjust the pump speed to match the changes.

Solar and the VS work fine. The most current version of the Easytouch firmware allows you to set a specific speed for solar - which will probably be faster than the standard pool speed setting.

There is a "bug" in the current Easytouch firmware. The firmware has a "prime" setting for the VS pump, where you can set a higher pump speed to run for 0-5 minutes, but this only works when the pump is initially turned on. It would be better if it would prime anytime the pump settings change, like when the solar is turned on to more quickly purge the solar lines of air.

The best part of using a VS pump, is that you can easily adjust the pump speed to optimize the solar flow rate.

mas985: What are the most efficient flow rates for solar? I have searched the internet, but have not been able to find any definitive discussions.

Fafco recommends about 0.08-0.125 GPM/Sq-ft. I run my panels at about 0.14 GPM/sq-ft and I get about a 3 degree rise input to output. On really hot days I get 4 degrees.

If the flow rate through the panels is too low, then the water gets too hot and starts to lose heat back to the environment. So at the low end of the recommended range, you would expect about 6 degrees of temp rise from input to output but that depends on the placement of the panels and your latitude. I would stick with at least 0.1 GPM/sq-ft or about a 5 degree rise between input and output.

Hello,

I have used the VF with my solar setup for 2 years now. The VF is just run in the Filter cycle. The solar panels are mounted about 10 feet high, on our patio roof. The pool is about 13,000 gal and is filtered during the summer from about 7AM till 7PM to take advantage of the sunlight for the solar. With a solar blanket and the solar panels, we have no problem bringing the pool up to 100 degrees(I was curious to see how hot it would get for a couple of days). We actually keep the pool in the mid to high 80's, which is very comfortable for our needs. I did not want to pop for big bucks with the controller, so I use the Suntouch mainly for the solar control, and when we are in the separate spa to turn on the heater with the remote control and switch the flow to the spa, and of course it controls our old Polaris 280(22 years old also). Our pool is 22 years old now. The price was right with this controller, for the pools simple needs, that is the reason for the Suntouch. Yes, the Suntouch operates separate from the VF, just like using 2 old mechanical timers, but that is fine . So, when the Suntouch cuts in the Solar panels, the VF pump just keeps up with its set flow rate, no priming as such is needed to get the water going up to the panels. So far after 2 years, there has been no problems at all using the VF with roof type solar. The only time I bump up the speed of the VF during the filter cycle, is using the features mode in the VF to feed the Polaris more pressure for the 280 to operate. Hope this helps a little with your question.
Ed

I wondered if there were any updates on this subject. Pentair continues to tell us the VF doesn't work well with solar. But the VS doesn't have a built in controller so we're looking at the VS+SVRS or the VS with Suntouch, which I guess could replace our existing solar controller.

I'm trying to understand what Ed's saying but I get lost.

Hello qofmiwok,

Do you still need an update? I haven't looked at the message board for awhile?

Ed

I replaced an old 2hp pump with a VS-SVRS. I already had solar that was working fine with the old pump. It would not work with the VS-SVRS because check valves somehow trigger the alarm and shut off the pump. Very disappointing. Not sure yet if I will get the VF or VS.

I too own a VF Intelliflo pump along with a I5+3 Intellitouch controller. I run solar also, and had a 1.5 hp before it smoked one day. I have no problems running solar with my VF pump. The setup is to find the min flow needed to get all your water "Toys" to work, like solar or a pool cleaner. I also have deck jets which shoot water in air back to spa, and a water flow of spa. I found that the solar liked 40gpm and the water fall liked anything about 40gpm to look right. So 40gpm is my high flow and 18gpm is the low flow settings making sure salt system worked ok with 18gpm. Everything is set to the 40gpm as far a water activators for solar, deck jets, water fall, and pool cleaner. The activators are partly opened all the way, to reduce system pressure as in solar about 22 / 24psi clean filter, or the reduce flow as in cleaner. I haven't had any issues running it this way.

I replace my failed 1-1/2 hp single speed pump with a Pentair Intelliflo VS+SVRS pump two months ago. I have found some interesting observations with a pressure gage on the high side of the filter and one on the 3 way valve before the solor or return by-pass. I have a rooftop solar system, screened in pool and live in Central Florida.

-Need to maintain a minimum of about 2000 rpm, 65 gpm, 565 watts//hr, at 8-9 psi at the filter to result in 5.5 psi(13 FT head) before ascending to the roof solar panels. Slower speeds result in the Watts N36-M1 vacuum release opening and letting air bubbles enter the panels. This appears to me the slowest speed I should run to operate the solar panels quietly.
-Speeds slower than 2000 rpm can be run if the solar is off.
-During freezing winter nights (10-15 days/yr) we will change the time of day to run the filter cycle at night(12AM-8AM) at 2,000 rpm with solar to avoid freezing pipes. The tempurature here, last winter, was 21 degrees several nights. Many here in the area lost pipes and pumps without circulation.
-A Goldline Aquastar II solar controller controls the 3 way valve and assures that the solar will be on below 40 degrees with the freeze protection selected on. The Aquastar uses the rooftop air temperature probe to determine the 40 deg air set point. The Aquastar is not recommended to operate the VS pump; it only runs the 3 way valve.
- Normal swimming season we have the VS pump run 1/2 hour at 3110 rpm, 1900 watts/hr, 9:00 AM, approximately 100 gpm in Schedule Mode on the Pentair. This really gets the pool cleaned up with debris on the bottom and the pool skimmed good. This is followed by Scheduling the pump 2,000 rpm for 6-8 hrs in Schedule Mode for 2-4 pool changes/da.
- This has realized an actual savings of 450 kw, $58 last month(September) compared to last years September bill Elect=$.13/kw). I expect lower costs during the upcoming winter months.
I am happy with the functionality and the energy savings of this programmable pump. I believe the payback will less than 2 years.

Phil, Leesburg, FL