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Thread: To Bypass or not to Bypass???

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    To Bypass or not to Bypass???

    Purchased an IC40 to go into my system run by my Intelliflo 3HP VS pump. I have a 6 foot straight run of 2 in PVC for the install area. The instructions discuss using a bypass loop when pump flow is going to exceed 80 GPM. 12 hours of the day my pump runs at 1450RPM, but weekly I run up to the full 3450 RPM for cleaning cycles which may drive flow up above 120GPM. In the winter, I will set the pump down around 750 RPM and run 23 hours. I'll pull the IC out and use LC during the winter. Would it be wise to put the IC on a bypass setup given the weekly cleaning rates of flow?
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Mod Squad jblizzle's Avatar
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    Re: To Bypass or not to Bypass???

    There is no reason to have to run the pump at full speed ... like ever.
    It is also highly unlikely that you are actually achieving a 120+GPM flow rate ... how did you determine that?

    Also note that lower speeds are not more efficient after a point. The most efficient speed is around 1000rpm.

    And even then there is no reason to have to run for 23 hours a day. Take a look at: Determine Pump Run Time
    Jason, TFP Moderator
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    Re: To Bypass or not to Bypass???

    Full speed...It makes cleaning more fun!

    Just a guess on flow, the pump is capable of 160GPM under certain conditions per the specs.

    My winter flow 23 hours per day is much about freeze protection, cheap freeze protection IMO with the VS. Up here ground temperatures are very low, winter air temps, especially overnight, dip well below freezing frequently. Cloudy does not help either, better safe than sorry.

    So, will the occasional over 80 GPM damage the IC40?
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Re: To Bypass or not to Bypass???

    Seems reasonable that rates exceeding 80GPM could be achieved at much lower RPM than full, have a look at this chart:
    https://flexpvc.com/Reference/WaterF...PipeSize.shtml
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Mod Squad jblizzle's Avatar
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    Re: To Bypass or not to Bypass???

    That chart has nothing to do with what the pump can generate. That shows what the pipe could potentially carry with assumptions based on pressures.

    You need to look at the performance curve for the pump. But even then, estimating head loss and flow rate is not trivial. Mark (mas985) has some spreadsheets in his signature that can try to estimate the flow rate given a small set of inputs and some built in assumptions.
    Jason, TFP Moderator
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    Re: To Bypass or not to Bypass???

    What's your clean and dirty filter pressure at 3450 RPM? That will give you a rough estimate of flow, from the pump curve. Let me know and I'll look it up.

    You need to think about velocity at that flow rate. You mention 2" at your pad and 120 GPM is above typical design criteria for 2". Is the rest of your pool plumbed with 2.5" or 3"? You mention cleaning as the use, so is it going through your filter? You may be exceeding it's capability at that flow rate.

    If the installation manual says max 80 GPM, and your pump can push more and you still want to do it, then I would definitely put the bypass loop in. I assume they show you a way to make it adjustable, so you can mess with it and get max 80 gpm but not fall under minimum for the SWG when you're running the pump slow. The manufacturer must not want that much turbulence inside the cell housing and around the plates or sensors. I agree with the previous posters that 80 GPM should be plenty to run the pool, but to each their own!
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: To Bypass or not to Bypass???

    This is my filter manual, it is the 420 SF model: http://www.pentairpool.com/pdfs/178558MOM.pdf
    When my pump is running at 1500 RPM, PSI is 2
    When my pump is running at 3150 RPM, PSI is 8-9
    "" 3450 RPM, PSI is about 11

    When I run my cleaner, I run around 2850 PRM, with the PSI around 5, the filter is 2 months old and I have not had to clean it yet.

    I do not have a flow meter, so my speculation that I'm above 80 at times is just that, speculation. I have two 1.5 lines coming from the skimmer and drain into one 2 in. line for all the above ground plumbing back to two 1.5 in lines to the step and main jets. There is no PVC rattle noise at any RPM on startup or stop, I have a clear check valve (.5 lb spring/flap) that is wide open when the pump is at 1500 RPM. I'm probably fine with 80 GPM, but I have not idea how to know what RPM produces that flow rate in my system, so I'm just trying to be safe about the plumbing in case me or someone else ramps it up higher at some point.

    To control the IC flow rate on a bypass you put a diverter between the in-out port of the loop.
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    needsajet's Avatar
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    Re: To Bypass or not to Bypass???

    For the Intelliflow VS 3HP, you're definitely well over 80 GPM if there's only 11 PSI at the filter at 3450 RPM, so yep, you need a bypass alright. You're not far off at somewhere around 120 or 130 GPM.

    80 GPM would be around 2000 RPM, based on filter pressure at 8 psi for that 3HP pump. Filter pressure approximates pump outlet pressure because there's usually very pipe and fittings between the pump and the filter. If that wasn't the case, it would be different.
    12k IG salt; glass beads in plaster; K-2006C, K-1766, CCL, and Aussie 4in1 (HTH); Pentair Eco800 1.2HP VS; Zodiac SWC 1.3 lb/day (25 g/hr); 25" filter recycled glass; OKU solar panels; 1/2 HP solar pump; Rebel (Warrior) pool cleaner; FlowViz; prior pool AG 10k | Read Before Posting to get the best possible advice | ... and this helped me a lot!: TFPC for Beginners

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    Re: To Bypass or not to Bypass???

    Thanks for the clarification on flow. I am considering doing a horizontal loop for the plumbing vs. a vertical loop, because I have the filter inlet pipe running into my filter right above the outlet stretch that I need to tap into. I'd like your opinion:plumbdiagsm.jpg
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Mod Squad jblizzle's Avatar
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    Re: To Bypass or not to Bypass???

    I do not think that is going to work well. You have no way to control how much water goes straight vs. the heater vs. the SWG.
    Jason, TFP Moderator
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    Re: To Bypass or not to Bypass???

    Consider my plan, see if it will work.
    When I want to run the cleaning cycle, I shut down the IC valve ( on the bottom where it says 3x valve) and the heat valve (the one that says 3xv going out to solar) and leave the straight shot valve wide open, normal no-heat pool circulation I leave the heat/solar shut down and open the IC valve wide and open the straight valve slowly until I find the spot where the IC is just happy with the flow, alternatively I may shut down the straight valve completely if I am running the VS very slow. When I want to operate under heat, I shut the straight, then open the heat valve 100% and the IC valve 100% adjusting either as flow dictates...will this work? I do not have a spot for the vertical bypass.
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Mod Squad jblizzle's Avatar
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    Re: To Bypass or not to Bypass???

    Is this all going to be automated? Sure sounds overly complex.

    I think I would want the SWG loop completely after the heater loop. So that you can run the SWG when you are running solar/heat.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: To Bypass or not to Bypass???

    I can automate up to 3 valves with the Easy touch, so that is a possibility, having trouble seeing how to do the bypass loop after the heater due to the way the pentair HP's do the inlet on one side, the outlet on the other and the space I have, maybe it is possible. That would take me down to 2 valves vs. 3.
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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    Re: To Bypass or not to Bypass???

    Update:
    Thank you to everyone who helped me sort through this install. I especially appreciate the input regarding pressure and flow-rate in my particular set-up. Based on that information, I placed the IC-40 on a bypass loop similar to the one diagrammed above. I'm able to dial in the flow to the IC-40 manually. In order to achieve a "green" flow indicator light on the IC40, the valve only has to be open approx by 1/3, the remainder of the water is shot straight or diverted to the HP. I like the flexibility of the system. Thanks again!

    Quote Originally Posted by needsajet View Post
    For the Intelliflow VS 3HP, you're definitely well over 80 GPM if there's only 11 PSI at the filter at 3450 RPM, so yep, you need a bypass alright. You're not far off at somewhere around 120 or 130 GPM.

    80 GPM would be around 2000 RPM, based on filter pressure at 8 psi for that 3HP pump. Filter pressure approximates pump outlet pressure because there's usually very pipe and fittings between the pump and the filter. If that wasn't the case, it would be different.
    18x36 in-ground, ~29k gallons, Pentair 3HP VS, Pentair CC+ 420, IC-40, EasyTouch Panel, In-ground cover, 100% DIY-reworked pad (thanks to help from this forum), TFP Test Kit, Near-antique heat pump...

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