IFC, Venturi Skimmer, Pump and Valve configuration

[harrat]

Hi TFP Family!

I'm banging my head against the wall lately trying to decide how I want to run my pool. Part of my confusion/indecision comes from having "professionals" initially configure my pool and then debate me when I talk to them about how I think the pool should be operated. These professionals tend to go with the tried & true, run it full blast, all the time, and I want to leverage the variable speed pump to bring costs lower. So to cut through some of the disinformation, I've got a couple questions I'm hoping this community can help me straighten out.

In my sig you can see I have the typical pool builder cadillac and the kitchen sink build. IFC, ic40, easytouch, etc. Part of this was because I didn't know much about anything and I listened to my PB. So here are a couple of my questions (keep in mind this is info gathering with a mind to how I want to run my pool, not necessarily that I plan on running it with certain things off or on, etc):

My plumbing stack (Simplified):



Venturi Skimmer: When I run the skimmer return only (the venturi lower port), my pump seems to have significant back pressure and reports only pushing 2gpm. Is this normal? If I crack the diverter even a little to the looped returns or the IFC the GPM jumps to 20+ at lower RPMs.

Looped Returns: If I intend to use the IFC, is there any reason to use them?

Skimmer intake: If I'm planning to use the venturi effect of the skimmer, is there a reason to use the skimmer intake at all?

A pool "professional" came out to help me with a couple things I wanted to do, because I had an idea of what I wanted, and he looked at my stack and said everything was all wrong. That I should just turn on the IFC and skimmer together, blast at high RPMs at all times to operate the IFC, turn off the skimmer intake and call it good.

My goal is to run the skimming function at low RPMs for long periods of the day, and then run IFC for targeted amounts of time on automed schedules. With easytouch I have 4 valves, though 3 of them are taken up for spa/spillway and booster pump activities. So I get one automated actuator to put on to put on the two 3 way diverters (without hacking in a 5th actuator... which I've gone down the road of a little bit and lets just say, it's not super straight forward but is still a possibility).

Since the skimmer return seems to only want to allow 2gpm through the pipe, it won't trigger the IC40 flow on its own, and I think it's caused some valve problems by having too much pressure build in the stack. This means that I can't turn off the looped returns altogether and just switch between the skimmer and IFC with automation. If I crack open the looped returns then the pump doesn't quite have enough GPM to make sure all the IFC heads pop up. One of the cycles pops 5 heads at one time which requires 45-50gpm through the IFC valve.

The way I see it I have 3 options:

1. Expanded automation: Figure out a reliable way to add a 5th valve actuator to my system (like I said, it is doable, but I've been partially down that road and it hasn't been a walk in the park). This would allow me to turn off the IFC, open the looped returns a little, and let the skimmer operate with the looped returns. (side note, I don't love where my wall returns are placed and feel like they impede cycling debris to the skimmer)
2. Do some significant plumbing changes to essentially swap the IFC and Looped returns location. If they swap, then I could link the skimmer and pool returns together and whenever the IFC is running the skimmer/returns would be off and vice versa when I wanted to run skimmer/return action at lower RPMS
3. Throw in the towel and run the IFC & skimmer together at all times and see if I can tune a lower RPM and ratio that still skims even though the IFC won't be running at optimal GPM to pop everything up.

I know how this community feels about some things (many don't like IFC... I get it... I have it, it's not going away for now... I'm thinking I'd like to know if it'll work for me), and I'm hoping I can get some good feedback towards a way forward. I'm also looking for sound, reasoned advice that gives me more information unlike this "professional" that had no interest in understanding what I was thinking and educating me. If you really believe that I need to consider something else altogether, I'm open to it, but I need to understand why, not just what how people feel about it.

Thank you!

 

[ajw22]

Why do you want to run the venturi skimmer returns without the looped returns? I would always run them together.

That then simplifies things to either be running your returns most of the day or your IFC for as long as necessary to clean the pool.

What pump and filter do you have?

Post pics of your equipment pad.

 

[1poolman1]

Hi TFP Family!

I'm banging my head against the wall lately trying to decide how I want to run my pool. Part of my confusion/indecision comes from having "professionals" initially configure my pool and then debate me when I talk to them about how I think the pool should be operated. These professionals tend to go with the tried & true, run it full blast, all the time, and I want to leverage the variable speed pump to bring costs lower. So to cut through some of the disinformation, I've got a couple questions I'm hoping this community can help me straighten out.

In my sig you can see I have the typical pool builder cadillac and the kitchen sink build. IFC, ic40, easytouch, etc. Part of this was because I didn't know much about anything and I listened to my PB. So here are a couple of my questions (keep in mind this is info gathering with a mind to how I want to run my pool, not necessarily that I plan on running it with certain things off or on, etc):

My plumbing stack (Simplified):

View attachment 552053

Venturi Skimmer: When I run the skimmer return only (the venturi lower port), my pump seems to have significant back pressure and reports only pushing 2gpm. Is this normal? If I crack the diverter even a little to the looped returns or the IFC the GPM jumps to 20+ at lower RPMs.

Looped Returns: If I intend to use the IFC, is there any reason to use them?

Skimmer intake: If I'm planning to use the venturi effect of the skimmer, is there a reason to use the skimmer intake at all?

A pool "professional" came out to help me with a couple things I wanted to do, because I had an idea of what I wanted, and he looked at my stack and said everything was all wrong. That I should just turn on the IFC and skimmer together, blast at high RPMs at all times to operate the IFC, turn off the skimmer intake and call it good.

My goal is to run the skimming function at low RPMs for long periods of the day, and then run IFC for targeted amounts of time on automed schedules. With easytouch I have 4 valves, though 3 of them are taken up for spa/spillway and booster pump activities. So I get one automated actuator to put on to put on the two 3 way diverters (without hacking in a 5th actuator... which I've gone down the road of a little bit and lets just say, it's not super straight forward but is still a possibility).

Since the skimmer return seems to only want to allow 2gpm through the pipe, it won't trigger the IC40 flow on its own, and I think it's caused some valve problems by having too much pressure build in the stack. This means that I can't turn off the looped returns altogether and just switch between the skimmer and IFC with automation. If I crack open the looped returns then the pump doesn't quite have enough GPM to make sure all the IFC heads pop up. One of the cycles pops 5 heads at one time which requires 45-50gpm through the IFC valve.

The way I see it I have 3 options:

1. Expanded automation: Figure out a reliable way to add a 5th valve actuator to my system (like I said, it is doable, but I've been partially down that road and it hasn't been a walk in the park). This would allow me to turn off the IFC, open the looped returns a little, and let the skimmer operate with the looped returns. (side note, I don't love where my wall returns are placed and feel like they impede cycling debris to the skimmer)
2. Do some significant plumbing changes to essentially swap the IFC and Looped returns location. If they swap, then I could link the skimmer and pool returns together and whenever the IFC is running the skimmer/returns would be off and vice versa when I wanted to run skimmer/return action at lower RPMS
3. Throw in the towel and run the IFC & skimmer together at all times and see if I can tune a lower RPM and ratio that still skims even though the IFC won't be running at optimal GPM to pop everything up.

I know how this community feels about some things (many don't like IFC... I get it... I have it, it's not going away for now... I'm thinking I'd like to know if it'll work for me), and I'm hoping I can get some good feedback towards a way forward. I'm also looking for sound, reasoned advice that gives me more information unlike this "professional" that had no interest in understanding what I was thinking and educating me. If you really believe that I need to consider something else altogether, I'm open to it, but I need to understand why, not just what how people feel about it.

Thank you!

Look at your flow rate like traffic. Your venturi in the skimmer is a very small one-lane dirt road and you are trying to push rush-hour traffic down that road. Open up a few lanes (return lines) and traffic flow greatly improves. You can only shove so much water through that skimmer

 

[harrat]

Attached is the photo

Right side stack is booster pump for waterfall/slide. In front of the filter is the main stack with the left most valve actuator being the far right of my diagram above, and the actuator above the SWG being the diverter between spa return and pool returns.

Two intelliflo 3.0hp motors. Pentair 520 Cartridge filter.

Why do you want to run the venturi skimmer returns without the looped returns? I would always run them together.

I don't mind running pool returns with the skimmer. It's just that if I'm going to be able to switch between IFC and skimmer/returns, I need another valve actuator, which the easytouch doesn't support out of the box. I'd have to wire in a 5th actuator. Or I'd have to swap the IFC and pool return lines in the plumbing to be able to close of IFC by itself.

I guess there might be some balanced configuration on the returns where there's enough flow on the looped returns to allow the flow sensor on the SWG, but not so much flow to prevent the IFC to have enough to work properly.

Also, the placement of one of the returns pushes debris towards the middle instead of near the skimmer, but thinking about that problem, I could/should probably get a directional port for the return to divert the return outflow towards the skimmer instead. I'm just not sure which part I can install in the current port to do that.

 

[jonpcar]

@harrat , you must be an engineer, haha. Here's my 2 cents.

I've done a lot of experimentation, and some enhancements, with my IFCS and you are asking the right questions. Unfortunately, with the "simplified diagram" and the one picture, I'm still not fully understanding your system and the problem you are trying to solve (effectiveness/efficiency/both?). Unlike many other IFCS implemented systems, yours has the components necessary to be a good one...but complications include the spa and the heater. Here are a few threads (amongst many, haha) where I have given my viewpoint on how an IFCS should be designed and run, they might be of help to you in understanding my philosophy:

In-Floor Cleaning Systems, Venturi Skimmers and LeafVac Containment

Well then, let me wrangle up a couple of folks that I know who like their IFCS. @proavia @jonpcar (I think Jon might be on vaca, and Gene might be too. But they’ll chime in when they get a chance.) Thanks Rob!! I would also like to see some comments on those containment systems and venturi...

www.troublefreepool.com

Appreciate feedback on a new pool

Hello. Glad I found this site and value all the info people are sharing. This is the first pool I'm building but had a pool at a previous home for a couple years. I have talked with 4 builders in the Phoenix area here's the latest plan we are considering. I had installed a Pentair VS pump and...

www.troublefreepool.com

First time pool owner: In-floor vs. robot

I love my IFCS system...but for 20 years was just “satisfied” with it....until I added automation a few years ago. I don’t need debris removal...mostly small things get in my pool including dirt, pollen, small leaves, etc. I would never get another pool...but if I did, initial cost of an IFCS...

www.troublefreepool.com

My advice for your case, and as you stated, this might not be possible the way you are currently configured (in particular, I don't see an actuator on what I think is your skimmer/main drain 3-way valve)
1) ignore the venturi skimmer return for NOW....turn it off. It is a device that might be useful but ONLY IF you have enough flow/pressure to run your IFCS popups effectively and efficiently
2) figure out a way to run the IFCS at HIGH RPM for a few hours a day, with full return flow to IFCS and full draw from the main drain
3) figure out a way to run your skimming/"additional chlorinating" at LOW RPM for as many hours a day as you want/need, with full return flow to the wall returns and full draw from your skimmer(s). Best to adjust your wall returns to develop a pool swirl that will aid in this skimming. I realize you have stated that this could be a problem for you.

It will take some trial and error to figure out the best results for your pool but the goal is a high IFCS RPM requirement of 3000 (mine is 2700) or less...and the low skimming/chlorinating RPM requirement is 1500 or less (mine is 1000, but I am currently in the process of putting in a SWG so that probably will go up). If you are able to accomplish this you can look at enhancements that might include use of the venturi skimmer...but I suspect the biggest benefit for you would be an automated heater bypass.

Some more pictures of your pad including the labels at various angles would probably help understand your current situation...as would a non-simplified stack drawing of your actual layout. It's difficult to understand/believe why that 3-way valve in front of the the heater, with the actuator on top, is selecting between the IFCS and the venturi skimmer return as your simplified drawing indicates. That just makes no sense. Do you have IFCS popups in your spa? How many zones do you have (5 or 6)?

 

[proavia]

Post a few more pics of your equipmemt pad from several different angles so we can better see the piping, valves, actuator and labels on the pipes.

Does the spa also have popups for the IFCS?
Post a pic of the water distribution valve(s) as well.

 

[harrat]

@jonpcar Thanks for the well thought out response. I am an engineer! I can't decide if I'm sheepish or proud that that shown through here.

I've attached my pool plan here for the plumbing and IFC layout. (I'm removing the AOP as I found out what many are saying... it didn't do much good, and yes I had the PB put in a vacuum port just in case it came in useful someday)

Do you have IFCS popups in your spa? How many zones do you have (5 or 6)?

Yes and there are 6 zones.

(in particular, I don't see an actuator on what I think is your skimmer/main drain 3-way valve)

Nope no actuator there.

but I suspect the biggest benefit for you would be an automated heater bypass.

@jonpcar - I'm curious why you suggest this would be one of the biggest benefits? I'd also like to know more about how you see optimal operation in an automated environment. Is it problematic for hard water to sit in the the heater for long periods of time (it doesn't get used super regularly... say once a month on average, sometimes more and sometimes less) or more problematic for it to run through there regularly?

From your other comments, I like what you're suggesting. And I think I need to double down on adding a valve actuator (or two!) to the system to get the automation I'm looking for. The venturi effect on the skimmer seems quite powerful, but I'm definitely interested in seeing how things work with the skimmer suction and returns only.

I also am needing to address the returns (or at least the problematic one) direction and replace with a fitting that I can direct in towards the skimmer effect.

@proavia Attached are a few of the views you asked for (and jonpcar and others as well) with labels. I'm definitely curious about your thoughts.

Thank you all for your input. I already feel better about some things after getting browbeaten by the pool dood.





Google Photos

 

[harrat]

Oh - one other thing @jonpcar re: venturi skimmer

It is a device that might be useful but ONLY IF you have enough flow/pressure to run your IFCS popups effectively and efficiently

@3000 RPMs all Popups pop with pool returns off and skimmer return/IFCS returns @ 50/50. That's how I've been running things recently, but I definitely want to optimize and think I have room for maneuvering on flow and RPM optimization.

As you mentioned, the real trick will be the automation/setup of all the valves to get to that place reliably. But if I at least know the end state I want to be in, I should be able to make it happen. Hopefully without breaking the bank..........

 

[ajw22]

Pentair and Jandy automatic bypass valves are set to bypass about 90% of the water and allow a small amount to circulate through the heater. That gives the benefit of less restriction and greater flow.

 

[proavia]

Oh - one other thing @jonpcar re: venturi skimmer


@3000 RPMs all Popups pop with pool returns off and skimmer return/IFCS returns @ 50/50. That's how I've been running things recently, but I definitely want to optimize and think I have room for maneuvering on flow and RPM optimization.

As you mentioned, the real trick will be the automation/setup of all the valves to get to that place reliably. But if I at least know the end state I want to be in, I should be able to make it happen. Hopefully without breaking the bank..........

Once you find that happy place to set the IFCS/venturi skimmer return valve, there is no reason to need to move it very often or automate it. Right now it is set to 50-50. Try 75 to IFCS and 25 to venturi skimmer.
On the suction side, set the skimmer/main drain to 75 skimmer and 25 main drain (or even 90/10).
This will allow some return water to help skim and the skimmer suction to work as well - possibly the best of both worlds. The main drains need to be open between 10 and 25 percent - at least that works best on my A&A IFCS.
Setting it this way may allow you to run at a lower RPM when needing the IFCS to clean. You're presently at 3000 RPM, you may be able to reduce the pump speed to 2900, 2800 or possibly lower and still get adequate IFCS cleaning. You'll need to experiment as every pool is different.

I leave my pool on the IFCS pretty much continuously. I run my wall returns at least weekly when I am out checking the equipment - sometimes when lots of people are swimming as well, so they don't stub they toes on the popups (well more so they don't play with or break the popups).

Are you on SRP or APS for electric? If on SRP, consider running the main pump 24/7. I am running at 1200 RPM for 20 hours and 2900 RPM for 4 hours (2 hours from 6am-8am and 2 hours from 4pm-6pm) - and with SRP (non-time of day), it costs me less than $20/month to run my pump and SWG. No idea how that would work with the higher APS rates.

Use the KISS principal. Don't be a slave to your pool and play around with the automation. It's fine to have automated valves - but be sure they will serve a purpose when automated.

BTW - your heater bypass is missing the check valve - at least in your schematic.

File:Heater Bypass Schematic.jpg - Further Reading

www.troublefreepool.com

 

[jonpcar]

@jonpcar - I'm curious why you suggest this would be one of the biggest benefits [automated heater bypass]? I'd also like to know more about how you see optimal operation in an automated environment. Is it problematic for hard water to sit in the the heater for long periods of time (it doesn't get used super regularly... say once a month on average, sometimes more and sometimes less) or more problematic for it to run through there regularly?

Harrat…here’s a bit of background for this opinion…

I didn’t realize you already had a bypass in place. Given that the heater is used sporadically, I think it is perfectly reasonable to manually close that valve ONLY when the heater is being used….otherwise leave it open and “bypass” the heater. I put “bypass” in quotes because one of this site’s experts has talked about this and my understanding is that some flow continues through the heater even though the bypass valve is fully open.

@mas985 ’s (Mark) view of how a heater bypass can be done is essentially how yours is done…it is a bit different than this site’s official recommendation as pointed out by @proavia. But that “official” recommendation enables the additional capability of "removal of the heater from the system entirely", which your simple bypass does not allow. For a pool user that has frequent problems with his heater this might be a godsend, otherwise….?

Anyway here are a couple of relatively recent discussions where Mark comments on this topic:

New pool plumbing help

In post 44, Mark talks about a 2-way valve that could “take the place” of the check valve, IF the capability to remove the heater entirely from the pool circuit desired. This discussed “2-way” valve is NOT YOUR two way valve. Note Allen’s concerns in the next post about replacing the check valve using that method.

In post 46, Mark specifies how the 3-way valve in that system could be implemented , and this is functionally equivalent to YOUR 2-way valve bypass implementation.

Un-bypass Heater frequency

Another example where his recommendation is to leave both paths open. In your case just open your 2-way valve and water flow will continue through the heater at some small rate AND through the valve with only minor restriction.

---------

The reason I feel a bypass of the heater is desirable is that heaters introduce flow reductions at ANY given RPM, but especially at the high flow rates required for IFCS/waterfalls/spas/etc. This is discussed throughout the boards many times…and some of these discussions have the actual numbers to demonstrate it.

Yes, they have made improvements to heaters as @ajw22 has pointed out, but it doesn’t seem to change the fact that you still must increase the RPM of the pump (and thus operational cost) to compensate for the additional head of the heater. Heaters impact low RPMs as well (such as when chlorinating/skimming) but obviously doesn’t impact cost as much.

Here is a discussion example (there are many) about heater bypass impact that actually includes some numbers and the involvement of another of this site’s experts. In this case, the conclusion is that in that system, the heater causes about ~2 to 3 psi loss and reduces GPM from 47gpm to 36gpm at an RPM of 2350. You are currently running your IFCS @3000 RPM and a flow rate of approximately 60-80+ gallons, so the heater’s impact to flow in your case is probably significantly higher.

High head loss from heater

Hi guys. After finishing my pool I had the heater bypass valve closed for the 30 recommended days (quartz pool). Rpm and gpm numbers were in the expected range at that point. Now that I opened the bypass valve in the heater (and everything else being equal than before) I'm noticing a very...

www.troublefreepool.com

A big problem you will have if you are trying to “measure” improvements to your IFCS operation is that there is no easy way. Only over time can you subjectively tell if the system is “cleaning better”. One thing you can measure, relatively easily, is electricity usage given that you have the tools/pump that allows that.

Another reliable measure of changes to actual IFCS popup flow is a PSI gauge at your IFCS valve distributor. NOTE: unfortunately that PSI value doesn’t correlate to your satisfaction of overall pool cleaning effectiveness…that simply takes experience and time, including a few monsoons, haha.

Unfortunately, you don’t have a PSI gauge at the IFCS distributor, but if you had one there, I can guarantee that when you open your heater bypass valve and you are running your IFCS popups at 3000RPM, you would see an increase in the PSI at that distributor. You could then “dial back” your pump RPM to match the previous PSI and be confident that you have not changed the flow through your popups. If you were happy with the previous IFCS popup flow before, you will be equally happy with them at the lowered RPM.

With a heater that is used only sporadically like yours (I don’t have one), it just makes sense to “bypass” it for the 95% of the time it is not in use. Simple to do, no automation changes, no valve additions. So in summary, ignore my comment about having an automated heater bypass...your current bypass valve is fine.

I’ll have some additional comments about your system but might have to wait until later. As you might be able to tell, you might have to wade through sometimes slightly different opinions about how you should implement/operate your pool, haha. In the end, of course, you decide.

 

[jonpcar]

Does your new diagram (which is very good, btw) match your implementation?...in particular I have questions about the bottom right. It seems that you have a couple 3-way valves in there that are "Actuator Capable" that are not shown correctly on your diagram. I could be looking at things wrong but can you verify? Note that in the diagram (that I quickly threw together) the left 3-way valve is not shown the way one would normally diagram it…but I do realize that the inlet is on the right side which can be diverted to either the left (IFCS) or bottom (Venturi return).

In particular, here is what I was wondering with my "3 way" labels. Currently, your picture seems that you have an actuator on the left one. More important is the possibility of moving that actuator to the right one.

By the way, I agree with @proavia that the skimmer venturi valve is normally just a "set and forget" type valve...and that it does provide some flexibility in your system. But, I have no clue why that valve on your system is automated...I've never seen that in a system before. It is also not connected in the ideal location. I suspect the plumber screwed up the placement of the “venturi return” and the “looped wall returns”. If those two were reversed (AND assuming my altered diagram above is what you have), it would be setup perfectly to select between "IFCS clean" and "wall return skim sessions" AND would allow you to use the vernturi action for BOTH. As it stands, you can get very close to what I view is ideal with NO pipe changes, but it wouldn't allow the use of both venturi and regular skimmers at the same time (it would allow venturi action during IFCS cleaning). But, you could take consolation in that 10s of millions of non_IFCS pools are implemented just like that without using venturi action when they skim, haha.

 

[harrat]

@jonpcar - I updated the diagram with some hexagons - red = 3way diverter, actuator CAPABLE. Blue = 3 way diverter Actuator INSTALLED (also has the grey square on it). I did it this way just for completeness.

... the “venturi return” and the “looped wall returns”. If those two were reversed (AND assuming my altered diagram above is what you have), it would be setup perfectly to select between "IFCS clean" and "wall return skim sessions" AND would allow you to use the vernturi action for BOTH.

THIS! This has been my own conclusion. So the plumber did install it in the order that's listed on the diagram (aerotor IS backwards in the diagram and in practice as you note, but all other things are correct in the diagram and reflected in real-world). But I wish that the looped returns would be swapped with the skimmer.

I am just having a hard time deciding if this really makes sense, and then, is it worth the expense to have a plumber come out and redo it correctly. And it's sounding kind of like you guys feel like it's probably not worth it. If I can get more traditional skimming working well for me, then venturi skimming becomes unnecessary for what I'm doing.

The main drains need to be open between 10 and 25 percent - at least that works best on my A&A IFCS.

@proavia @jonpcar You guys feel that this is the better setup for getting the IFCS to operate well? I had one pool pro tell me that all suction should come from the main drain to maximize the effectiveness of the IFCS... And even to the point of turning off skimmer suction entirely because the venturi will get plenty of flow by itself.

I can definitely see a path to automating things like you both suggest in getting more traditional skimming going (need to get some directional wall returns going) if I can leverage up the suction from there and move automation to the 3way by the looped returns instead.

And I definitely identify with the KISS principle @proavia. Your call out to focus on what's important rather than trying to achieve some pie-in-the-sky ideal of hands off automation that requires tweaking is well taken. All I really want is to have a pool my family and friends want to swim in, that doesn't require me to be out there all the time doing stuff.

Thank you guys for your insight. I was traveling this week for work. I intend to test some things out this week and see how it goes.

 

[proavia]

You guys feel that this is the better setup for getting the IFCS to operate well?

Somewhere in that range is where mine has been set for 24 years and it works just fine. You need to find where in that range yours works best.
Once set - leave it alone. Remember where it's set and exercise the valve thru its entire operating range every month or so.
No need to automate the valve below shown w/red hexagon.




Your AVSC Dual Inlet Channel Drain allows connecting two pumps. One line goes to the filter pump and the other to the water feature pump. In essence, it is two separate drains incorporated in one housing and is VGB compliant.




I agree with @jonpcar that the lines for the venturi return and looped returns should be reversed. Easy enough to do with some cutting and re-piping below the valves. No need to cut out the valves, just the pipe below it and reverse the pipe locations. Again, no need to automate the venturi return valve, shown below w/red hexagon. Set and forget.....

 

[jonpcar]

@harrat, I wouldn’t rush to make any pipe changes until you figure out what might work best. This is long, but I get excited about a fellow engineer who seems to want to dive into IFCS functionality, haha. Hopefully it makes sense.

First a question. It seems that you have a gpm flow estimator in your system…is it what you are reporting from the pump? Those are not always accurate (especially at extremes) but they can be extremely helpful in determining the impact of any changes you are experimenting with. Can you also get power (watts) numbers?

A bit more background for my recommendations. Mine is one of the earlier IFCS implementations, I’ve had it since 1993. Like Gene, I was ‘satisfied’ with it for 20+ years until I did my pool renovation and added: (1) variable speed pump and (2) valve automation. This allowed me to implement the “low RPM skim most of the time” and “high RPM IFCS clean some of the time” strategy. WOW what a difference…I was astonished at the cost savings and the improvement in cleaning despite running the IFCS less than half the time I had previously. Admittedly, some of my previous operational methods were just stupid. Today I would never recommend including an IFCS without automation, or at least the possibility to add it in the future which requires those two 3way valves: one at suction for main drain/skimmer, one at return for wall returns/IFCS.

I did a 2nd round of improvements on my system in 2016 when I discovered that my IFCS system was literally starved for water flow (my return lines/valve are only 1.5” and my suction line is 2”). A brief explanation is that when pushing water returned through the IFCS, my older system was limited to about 40gpm which obviously limits suction flow to that same number (in flow= out flow). Since IFCSs rely on filtering (water turnover) to extract the stirred-up debris, it is slow process to filter the debris at that gpm. The solution was easy to think of, but less easy to accomplish: simultaneously open my wall-return valves to increase return/suction flow (to about 60gpm…a 50% improvement), of course with a higher pump RPM to maintain the same PSI at the cleaning heads. At that time, I would have loved to have your venturi skimmer where a simple valve turn might have accomplished that goal. With that change, I saw another marked improvement in performance and reduced my IFCS clean time down to its current number of about 3 hours/day. I also found about pool swirl at that time, which dramatically improved low RPM skimming.

Anyway, modern IFCS implementations shouldn’t have my “starved for water flow” problem if they stick to manufacturer’s current recommendations like it seems yours did…2” IFCS distributor valve, 2” return lines to popups, 2” wall return lines, 2.5” suction line (for sure did they do this on your main drain?). You should be able to accomplish 80+gpm in your system with those implemented specifications.

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When it comes to IFCS operation, as @proavia and I have both discovered and preach, an ounce of prevention is worth a pound of cure. Skimming (low cost/low pressure/low RPM water) is essentially free. My skimming currently runs at 130 watts but will go up with the SWG I am adding. The more debris that can be extracted from the pool surface before it sinks to the bottom will decrease the time you have to run your IFCS.

IFCS cleaning (high cost/high pressure/high RPM) water is much more expensive. During IFCS cleaning, my pump runs at 2700 RPM and the wattage is about 850 watts. Like Gene, I only need to run my IFCS a few hours each day to make me happy…which always will be a personally subjective measurement. If someone always wants/expects that last leaf or seed out every day…they will never be happy with an IFCS.

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Venturi Return Recommendation

Take off the actuator from the IFCS/Venturi Return and then manually experiment with this valve. It’s hard to justify keeping that actuator there when there are better options for it; eventually move it to the other location that I mentioned: Wall Return/IFCS+ selection. Next, manually set the IFCS/Venturi Return valve to either (A) 100% IFCS or (B) 70% IFCS and 30% Venturi Return.

(A) From your engineering drawings, your system requires about 50gpm to the IFCS head to drive your popups. The advantage to getting the full required flow (or more!) to the heads is that their throw should be maximized and you will have fewer dead areas in your pool, ideally zero. Most of my zones only have 2 popup heads, which are way different from your heads, so I push about 20 gallons through each. As a result, the popups do a great job of pushing stuff around the floor AND keeping any grime from collecting on the walls. This probably makes me an idiot but I have only felt the need to brush my pool walls about 7-8 times (total) in the last 9 years… usually after a monsoon or near-monsoon dust storm. 50gpm (total) to each zone might work the same for you, but I have no clue how your “engineering specifications match real world results”. You just have to try it.

(B) As you found out when you did your valve turning experiment, “% turned” numbers have almost nothing to do with the % flow through a 3way valve. Between “30% to 70% turned” effectively means both paths are full open and the flow through each is fully determined by the downstream head of each path and not by the valve itself; that’s only a slight exaggeration. (B) So setting the Venturi/IFCS selection at 30% Venturi should insure that you get the full ~10gpm required to the Venturi Skimmer. By opening this Venturi Return valve, you will increase your IFCS cleaning gpm requirements to a minimum ~60gpm (50gpm for popups + 10gpm for venturi) . You WILL have to increase you pump RPM, which will probably result in ~25%+ increase in wattage, but it could be worth it to you. You’ve added higher cost skimming (high pressure water = high cost) to the IFCS cleaning, but you’ve also enhanced the ability to more quickly filter the crud out of the water as the IFCS stirs it up (filters out at 60gpm vs 50gpm, similar to the issue I had in my starved system described in the 2nd paragraph of this post).

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Main Drain/Skimmer Return Path Recommendation

I recommend you put an actuator on your Main Drain/Skimmer Valve. Drawing 100% from the main drain when running the IFCS increases its effectiveness. I know this is not consistent with Gene’s advice but your system can support this. I say use it! At the very least try it. SIDE NOTE: I believe Gene’s system is similar to mine which implements a skimmer/main drain suction diverter in the skimmer itself…a spaceship device…is that right @proavia ? I have had to “jury rig” my system to almost accomplish "100% main drain suction" during high RPM IFCS cleaning.

This is why I think main drain suction is so important. For IFCS pools with 6 zones, ONE COMPLETE POOL SWEEP takes approximately 1 to 1 ¾ hours. Here is where I am going to guestimate some numbers to illustrate the point.

Let’s say a particular IFCS system can filter 40% of the pool floor debris in ONE COMPLETE POOL SWEEP. After 3 passes (roughly 4 hours), that system will have cleared: First pass (.4) + 2nd pass (.4 x .6 remaining) + 3rd pass (.4 x .36 remaining) = .784 = 78% of the debris. 78% of the debris is cleared after 3 passes. Note: for four passes this number is 84%

If a higher % can be cleared during one sweep there can be a significant difference. If that number can be raised from 40% to 50% of the debris being cleared in ONE COMPLETE POOL SWEEP, then the math is as follows: First pass (.5) + 2nd pass (.5 x .5 remaining) + 3rd pass (.5 x .25 remaining) = .875 = 88% of the debris. 88% of the debris is cleared after 3 passes. Note: for four passes the number is 94%

Increasing the “% of debris cleared per sweep” is where the main drain comes into play…think of it as the black hole you are trying to randomly push the debris to fall into. The more “vacuum” power (gpm sucked into the main drain), the greater the volume/area and the chance that any nearby debris will get sucked into it. If cleaning the bottom of the pool of debris is an issue for a given pool with an IFCS, drawing higher gpm through the main drain is a key way to improve it. The simplest way to do this is to divert all suction to the main drain, especially if that is not already being done. Other methods can do it but will be less cost efficient, for instance: increasing pump RPM, if not already maxed out.

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This is already way too long so I’ll try to finish quickly for now. Putting actuators on the two valves that I keep harping on (Main Drain/Skimmer Suction, Wall Return/IFCS+) allows you to almost fully implement what I view is ideal (but you’ll have to check that yourself). The beauty is that these valves work in tandem (similar, but not exactly to spa/pool suction/return valves) and can be controlled by the same logic. I am not sure if Intellicenter will allow two actuators to be controlled by the same wires but that is effectively what you need to accomplish this. Also, don’t forget bypassing the heater, it can only help.

Personally, I would suggest you manually experiment with the valve settings before you even add the actuators. If you really want to get ambitious I would suggest taking some data on various positions to help you make a more informed decision (gpm/watts/filter psi). If you want more information on that let me know.

Also, skimming is not about pointing wall returns towards the skimmer. It’s about creating a pool swirl so that debris is circulated around the pool, and thus going by the skimmer possibly many times until it gets sucked in. On my pool, only one of my two pool returns is helpful for this purpose, the second one is useless.

Finally, don’t change any pipes yet…first make sure you know what you are going to get.

 

[proavia]

I believe Gene’s system is similar to mine which implements a skimmer/main drain suction diverter in the skimmer itself…a spaceship device…is that right @proavia

Nope - mine has a separate skimmer line and a separate main drain line homerun to the pad. Both run thru a 3-way Jandy valve, into the LeafVac and then to the pump.

I have a 5 zone system. Each zone has 3 popups, except the steps/sun shelf has 4 (1 low flow and 3 regular). All are Type 2 heads - I wish they were the venturi type heads as, in theory, they should require less flow from the pump due to the venturi design. Initially, I had a 2hp single speed for 12-ish years, then switched to a VS. The VS is a BIG savings in electric consumption.

 

[harrat]

First a question. It seems that you have a gpm flow estimator in your system…is it what you are reporting from the pump?

Yes - I use the GitHub - tagyoureit/nodejs-poolController: An application to control pool equipment from various manufacturers. to interact with the easytouch and be able to tell google to warm up the spa etc . It reads data from the pumps and presents it very easily so that's the reference I have to what flow and energy consumption. As I follow the links in your sig though, you know all about automation and working digitally with pool equipment.

It is good to know that this is likely somewhat not accurate to actual flow, but can be used (and has) for comparison. Thank you for all of that information!

I'm still digesting a bunch of that information. But a couple things of note:

The diverter valve for the looped returns is malformed and leaking periodically. I have replaced all the guts and this pool professional who told me there's no way the whole thing has to be replaced, opened it up and lubed it all and replaced gaskets.... twice. And still a good drip. So I'm going to be cutting that valve out anyways... soonish.

I'm definitely going to be looking into updating my wall return ports for better "swirl". I knew what you mean, the issue I'm having is that my venturi return is actually perfectly placed to create a nice swirl that brings debris to the skimmer. But the returns are all non directional and push towards the center. Especially the one that is the last stop in the swirl path towards the skimmer. So debris ends up collecting in the middle when the wall returns are running. Plus I think there's some balancing that I need to do with flow, etc, as there's much less water flowing from the returns on the far side of the loop as opposed to the near side.

And this week, I've been operating my skimmer/main drain at 50/50, the IFCS/skimmer return at 50/50, and the wall returns off. Just operating with the valves set statically that way at lower speed and higher speed, I think I'm getting a cleaner pool than I have in months. I'm getting plenty of flow to pop up the heads at something like 3100 RPMs and even though the heads don't pop up on the lower speed (2100RPMs), everything seems to cycle through ok and skimming action is decent.

My plan is to look at adjusting the wall returns so that they encourage swirl and then see about moving pipes since I have to cut a 3-way out anyways and see where that gets me. I know that I would prefer to be able to adjust the skimmer venturi return independently of whether I am operating the wall returns or IFCS. I am a little hesitant to that drastic, but I don't want to replace this valve, and then cut everything again later. I suppose it could be done so as not to cause issues now and then later, but it feels like if I'm going to be doing surgery anyways, might as well make it work how I want it to.

Oh - and I was thinking about your comment on IFCS efficiency.... I'm thinking about adding my feature pump into the cleanup routine, maybe at lower levels... It draws from the main drain and has a large volume of water that flows through it (pump says 70+ gpm at 3000rpm). It has a cyclone pre-filter and does do a decent job of getting debris/dirt out of the water (I like using it after dust storms!). Could be another way (albeit somewhat gimmicky) to add some extra heft to the IFCS cleaning cycle... though energy expensive.

 

[jonpcar]

The diverter valve for the looped returns is malformed and leaking periodically. I have replaced all the guts and this pool professional who told me there's no way the whole thing has to be replaced, opened it up and lubed it all and replaced gaskets.... twice. And still a good drip. So I'm going to be cutting that valve out anyways... soonish

@harrat, if you are changing that valve and rerouting those pipes to swap those two return paths anyway, then remove this particular 3-way valve entirely and replace it with a “tee” and a 2-way valve that allows flow to the Venturi skimmer return…exactly like your aerator is plumbed. Use a good actuator capable, jandy valve…you never know what you might want do in the future. That’s exactly how this valve is usually plumbed since venturi skimmers require only about 10gpm to operate.

As you found out, you never want to be able to “divert” all your return flow to the Venturi skimmer return, it is almost a dead-head situation for the pump (your reading was 2gpm)…in reality the gpm flow was probably somewhere in the low teens. Still very bad for your system when the pump is running at any speed.

This recommended 2-way valve implementation will disable any accidental dead-head: someone unknowingly turning the valve OR if you end up automating that valve will avoid problem with actuator failure. It will still allow you to send flow to the Venturi skimmer return to run it effectively for both high RPM IFCS cleaning and low RPM skimming.

Oh - and I was thinking about your comment on IFCS efficiency.... I'm thinking about adding my feature pump into the cleanup routine, maybe at lower levels... It draws from the main drain and has a large volume of water that flows through it (pump says 70+ gpm at 3000rpm). It has a cyclone pre-filter and does do a decent job of getting debris/dirt out of the water (I like using it after dust storms!). Could be another way (albeit somewhat gimmicky) to add some extra heft to the IFCS cleaning cycle... though energy expensive.

We have seen a number of IFCS implementations that use 2-pumps…there are slightly different variations but usually are setup as one pump to push stuff around via the IFCS popups, and the other pump to filter the debris. My opinion has been is that without a filter on both pumps, this is a major source of Inefficiency and is usually a kludge to overcome potentially poor performance of the popups: getting high enough psi at the popup distributor valve to allow required gpm to flow the popups. This is done mainly in more complex IFCS systems: large pools - 20k gallons+, 7+ IFCS zones which requires two IFCS popup valve distributor, spas, water features, solar, heaters, etc.

Your system is different, and definitely interesting. You “kind of” have two filters, I have no clue how effective the cyclone filter is…a regular filter would probably be better. BUT, if that cyclone is effective, your IFCS system would definitely perform better with that 2nd pump running, at a HUGE overall cost to efficiency. Your main drain becomes a super “black hole”, haha. In this era of $100K+ pools, what’s a few more dollars a month in electric bills? Before I retired, I threw $$$‘s at everything including my pool to save time.

EDIT: The biggest problem in using this method will be that you only have the option to return this increased, 2nd pump suction/flow through your bubblers, slide, or waterfall. That will raise your pH significantly and so this “trick” would only be useful in bursts…like after a monsoon storm as you currently do.

With your 14K gallon pool, you should be able to make your IFCS system work great without running that 2nd pump, but it is nice to have that 2nd pump as a back-pocket option, and definitely worth some experimentation.

 

[harrat]

Hi @jonpcar & @proavia - I just wanted to reply with thanks for your advice. I've been running my system with the switched plumbing and updated venturi valves for a couple months now and the pool has been running great. I really feel like I'm getting it fully dialed in, and this has been a great help. Appreciate it!