DavidJ

Pipe size. Not with these new variable speed pumps. Could you elaborate on what you say here? Are you talking about pipe size on the intake and/or the output? Does a bigger pipe size tend to fill the basket more or the other way around? Why is it that a variable speed pump running on higher speeds would be any different than a regular pump in regards to how full the basket is? Thanks.

I have seen some Pentair Intelliflo pump installations where the basket is only perhaps half full when running, even on higher speeds. There are no bubbles coming into the pool that would indicate a suction side leak and the pressue on the filter ranges [in the one location that I recently noticed] ranges from 3 - 12 PSI between default settings 2 and 4 so there is very little back pressure on the pump. All the pumps that I've observed are located above the water level of the pool. What is it that determines if the pump basket will be full when operational or only partially full? Is a partially full basket indicative of a problem? Thanks.

Is there a downside to installing the VRV lower like this?

Thanks for the response here. I should have mentioned that we are not installing a solar pool heater at this location - just PV and solar thermal. They don't heat the pool often enough to justify it. I'm just trying to show them other areas of opportunity at the pool. Regarding the VRV, have you ever seen anyone install a motorized or solenoid operated valve that could be positively controlled at will, thus allowing slower flow rates? It may or may not make sense depending on what the minimum flow rate to keep the VRV open is compared to what reasonable flow you should have based on the number of panels on the roof.

I am a solar contractor and trying to advise a client on other ways to reduce energy consumption. In the pool area I have advised that they install a variable speed pump such as the Intelliflo and I'm also planning to suggest that they change out their DE filter for a large surface area cartridge filter to reduce pressure. The 2" piping coming into the pool heater (that is infrequently used) has a number of elbows in it to make the connections work out in a tight space. Would you pool experts consider it reasonable advice to suggest plumbing in a bypass around the heater for the seasons that the heater is not being used? One obvious downside is that it involves greater homeowner intervention in a now more complicated system and we know that this can bring more problems. The upside should be a further drop in pressure. I'm not sure if this will materially affect the longevity of the heater. Do most heaters have a safety system that will not permit them to run if water is not moving through it? Also, is it your professional experience that a good cartridge filter will operate at a materially lower pressure than a DE filter? Thanks.

BTW, there are calculations that you can do, to get precise answers to your questions, but i'm too old to remember. I figured that you arent going to dig up your yard to replace all your pipe at this point anyway. These pumps work real well for water features, waterfalls especially. It gives you the ability to dial in a speed that looks good, or set different speeds for the (waterfall) sound. Was your answer about 2.5 or 3" pipe referring to California's requirements or what it would take to max on of these pumps out? Thanks to you and others for your responses here.

So if you were to truly max one of these out, what size pipe would it take to do it justice? I realize that this is not wise as you would greatly compromise the efficiency running it at the limit of its capabilities, but an interesting thought nonetheless. Did I read somewhere that California is now dictating larger pipes on pool installations because of the efficiencies of bigger pipe? Do you know what RPM you are at where it starts to cavitate with 2" pipe? How can you tell that it is cavitating or starting to cavitate? I've never ran one up that high.

I'm curious how soapy water would help with a vacuum leak. I can understand if air is blowing out but wouldn't think you could see much in a vacuum situation. You list a number of important things to check for. In this case, since we don't seem to have much if any bubbles, I think we were probably just led astray by the excess water in the strainer basket with this particular pump. There are three older PVC ball valves that control water coming from the skimmer, main drain and side pool port respectively that should probably be replaced, just to be sure. Right now they are plumbed so that they could all three be closed which seems like it is asking for trouble, as opposed to using a three way between the side port and the skimmer so that no one could accidentally cut off complete flow to the pump. Thanks for your help.

Well I'm glad to hear that the partial filling of the strainer basket is not indicative of a problem, and that you've observed this multiple times. I was thinking that that was a pretty good sign of a compromised suction line. Are these Intelliflo models the only ones that behave that way? It is my understanding that the wet end of the pump is the same as some of their other models. Certainly the generally slower speed that people often run these will make it less likely that they will fill up. In this case there are no visible bubbles coming out of the pool and there doesn't seem to be much (if any) air building up inside the filter. Will a suction leak of any size materially affect the pump performance? Thanks again for describing and relating your experience with this particular pump. It may have kept me from pulling my hair out trying to eliminate that strainer basket air when it should apparently be considered quite normal (with these particular pumps).

I am trying to determine if there is a leak on the suction side of a pool pump. The pump in this case is a Pentair Intelliflo VS 4X160 (great pumps in my opinion). It is probably 25' from the closest end of the pool. Elevation wise, it is probably about 2' above the pool water level. On the suction side it has a skimmer, a bottom drain and a vacuum port with dedicated old red-handled plastic ball valves. Isolating any of these doesn't materially change the amount of water in the strainer but it is possible that all three valves allow air in. The water coming out of the pump goes to a cartridge filter, heat pump, Chlorine generator and pool. I have a few questions that will hopefully help me understand what to expect better. I have read some of the suggestions here as to common sources of air intrusion. 1. Should the clear strainer lid on the pump always be solid water with no air visible under the lid? On this pump, the clear strainer is not smooth on the bottom. It was molded in such a manner that it has it has pockets that can trap air. I frequently see air compartmentalized under the lid in these pockets. At the lower speeds the basket might only be partially filled. Should that be expected? I see more air than you would expect, even at medium speeds. I'm sure that I've seen pumps at other people's homes where there is no visible air. How long should it take to flush out all or most of the air from the strainer basket once water starts flowing, after you've removed the lid and had to reprime? The crazy thing is that I don't really see air coming out the discharge line to the pool. I don't know if it get's trapped in the Hayward cartridge filter housing. Will air pass through the filter if the water hasn't been displaced with air yet? I need to monitor that more carefully and see if it is filling up. Those filters have a manual air bleed valve on the top of the filter. 2. How much air infiltration does it take to measurably degrade the pumps ability to move water? Someone told me that an old professional trick was to light a cigarette near each potential source of leakage (on a very calm day) and see if it gets sucked in. Does that work and would it detect a tiny, but suction reducing, leak? 3. Are there any other ways to pinpoint the source of a suction problem? Thanks for your insight and suggestions at isolating a problem.