- Dec 14, 2021
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- Pentair Intellichlor IC-60
New Construction Started - Willis, TX (north of Houston)
- Thread starter Duffatola
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- Dec 14, 2021
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I read this earlier in the thread. Is this what we're looking at in terms of GPM for each system? If yes, it's significantly higher than 138 GPM.
Feature = 235 GPM
Infinity Edge = 190 GPM
If you want to have the ability to get to 200 GPM, the total system head loss has to be kept below about 33 feet of head.
That’s the total head, which includes the suction and return plumbing, check valves, fittings and any filters.
You might find that 200 GPM is more than you like for either feature, but I would want to try to preserve the ability if possible so that you have it available if you want it.
If it’s too much, you just reduce the pump speed.
The suction head loss is 7.9 feet for 100 feet of 3” PVC pipe vs. 2.1 feet head loss for the 4” PVC pipe, so that’s only a 5.8 foot head loss difference, which is not too bad.
The filter is the biggest factor with about 30 feet of head loss at 150 GPM (13 psi).
However, with a manual bypass around the infinity edge filter, the head loss from the filter goes down to about 3 feet of head.
Besides the head loss costs, the suction needs to stay away from the cavitation point at the eye of the impeller, which happens when the suction head loss is greater than about 30 feet.
Assuming that your local code does not specify the velocity limit for suction plumbing, 3” PVC pipe should work.
That’s the total head, which includes the suction and return plumbing, check valves, fittings and any filters.
You might find that 200 GPM is more than you like for either feature, but I would want to try to preserve the ability if possible so that you have it available if you want it.
If it’s too much, you just reduce the pump speed.
The suction head loss is 7.9 feet for 100 feet of 3” PVC pipe vs. 2.1 feet head loss for the 4” PVC pipe, so that’s only a 5.8 foot head loss difference, which is not too bad.
The filter is the biggest factor with about 30 feet of head loss at 150 GPM (13 psi).
However, with a manual bypass around the infinity edge filter, the head loss from the filter goes down to about 3 feet of head.
Besides the head loss costs, the suction needs to stay away from the cavitation point at the eye of the impeller, which happens when the suction head loss is greater than about 30 feet.
Assuming that your local code does not specify the velocity limit for suction plumbing, 3” PVC pipe should work.
The sheers will take up to about 150 gpm to 180 gpm at full power.
The bubblers will require 20 GPM each or a total of 40 GPM.
To run the sheers and bubblers at full power, you will need about 190 t0 220 GPM.
The maximum flow that you could probably get from the XF is about 200 GPM under ideal conditions.
If we allow for 160 GPM for the sheers and 40 GPM for the bubblers, that makes 200 GPM,
It’s highly likely that you will find a lower flow adequate most of the time as full power can get loud.
For the Infinity edge, 200 GPM with a filter bypass is probably the best you can do.
With no filter bypass, the flow should be limited to about 150 GPM.
The bubblers will require 20 GPM each or a total of 40 GPM.
To run the sheers and bubblers at full power, you will need about 190 t0 220 GPM.
The maximum flow that you could probably get from the XF is about 200 GPM under ideal conditions.
If we allow for 160 GPM for the sheers and 40 GPM for the bubblers, that makes 200 GPM,
It’s highly likely that you will find a lower flow adequate most of the time as full power can get loud.
For the Infinity edge, 200 GPM with a filter bypass is probably the best you can do.
With no filter bypass, the flow should be limited to about 150 GPM.
In addition to the actual length of pipe, you also have to add the “Equivalent length” for each fitting.
For example, if you have 75 feet of 3” PVC pipe and (6) 90s, each 90 is equivalent to about 7.7 feet of straight pipe.
So, the pipe length is considered to be 75 + 6(7.7) = 121.2 feet total pipe length.
Lasco and others have pressure rated "Sweep" 90s, which are a little bit better for hydraulic efficiency, but not critical.
Sweep 90s are preferable to regular hard 90s.
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- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I told the PB early on (well prior to signing the contract) that I wanted to use sweep elbows and 45's as much as possible in lieu of conventional 90° elbows.
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
I am not aware of any code regarding velocity limit. We live in the county, could these codes be municipal?
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
This is what I think I understand regarding 4" versus 3" for the infinity edge drain and water feature suction:
- 4" is better than 3" in order to get near full capacity of each pump.
- 3" will be okay on the infinity edge but using the filter bypass is a good idea when maximum flow is desired knowing the max is probably 200 GPM.
- 3" will be okay on the water feature suction understanding the sheers will use 150-180 GPM at full speed. The bubblers will require 40 GPM more, therefore at full speed the sheers will use ~160 GPM and 40 GPM will be allocated to the bubblers which will max the pump out at 200 GPM.
- 3" is only okay if there is not a maximum velocity suction code which is <6ft/sec.
I’m estimating the suction head loss at about 15 feet, which is a little bit higher than I would like on a suction line because you always want a good margin of error to account for anything you might miss or underestimate.
Part of the issue with the infinity edge is that the pump sits significantly higher than the surface of the basin water, which adds extra head loss (Static head loss vs. dynamic head loss).
How high will the pump sit above the water in the basin?
I don’t think that you will hit cavitation at full speed with 3” PVC pipe, but I can’t say for sure.
If I had the final say on the pipe size, I would go with 4” to be extra conservative.
Below are two references for hydraulics that might be helpful.
Part of the issue with the infinity edge is that the pump sits significantly higher than the surface of the basin water, which adds extra head loss (Static head loss vs. dynamic head loss).
How high will the pump sit above the water in the basin?
I don’t think that you will hit cavitation at full speed with 3” PVC pipe, but I can’t say for sure.
If I had the final say on the pipe size, I would go with 4” to be extra conservative.
Below are two references for hydraulics that might be helpful.
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
When the basin is at normal level the pump will be ~3' higher than the top of the water.
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
The infinity edge is 2'-6" above the water level in the basin.
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Thanks. I downloaded the Hayward doc long ago. It made my head hurt. I've learned a few things since but the document is still a bit daunting (for me).
Ok, 3" will probably be ok.
The below standard allows for up to 8 feet per second in suction and return plumbing.
For 3" PVC pipe, that's 184 GPM.
Size.......6 ft/sec......8 ft/sec.
1.5"...........38...............51 gpm
2"..............63...............84 gpm
2.5............90.............119 gpm
3.0".........138............184 gpm
4.0"........238.............317 gpm
ANSI/APSP/ICC-5 2011 American National Standard for Residential Inground Swimming Pools
Published on Mar 1, 2020
This standard applies to permanently installed residential inground swimming pools intended for noncommercial use as a swimming pool by not more than three owner families and their guests and exceeding 24 in. (61 cm) in water depth. EXCEPTION: Separate ponds, fountains, decorative water features, and reflecting pools or other similar bodies of water that are not intended for bathers are outside the scope of this standard. Includes Addenda A approved June 28, 2012.
issuu.com
The below standard allows for up to 8 feet per second in suction and return plumbing.
For 3" PVC pipe, that's 184 GPM.
Size.......6 ft/sec......8 ft/sec.
1.5"...........38...............51 gpm
2"..............63...............84 gpm
2.5............90.............119 gpm
3.0".........138............184 gpm
4.0"........238.............317 gpm
ANSI/APSP/ICC-5 2011 American National Standard for Residential Inground Swimming Pools
Published on Mar 1, 2020
This standard applies to permanently installed residential inground swimming pools intended for noncommercial use as a swimming pool by not more than three owner families and their guests and exceeding 24 in. (61 cm) in water depth. EXCEPTION: Separate ponds, fountains, decorative water features, and reflecting pools or other similar bodies of water that are not intended for bathers are outside the scope of this standard. Includes Addenda A approved June 28, 2012.
ANSI/APSP/ICC-5 2011 American National Standard for Residential Inground Swimming Pools
This standard applies to permanently installed residential inground swimming pools intended for noncommercial use as a swimming pool by not more than three owner families and their guests and exceeding 24 in. (61 cm) in water depth. EXCEPTION: Separate ponds, fountains, decorative water...
- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
In other words, 3" will probably be ok on both the negative edge drain line as well as the water feature suction?
I reached out to the PB and inquired about a max suction code but have yet to hear back. I found a State of Texas document which requires exempts single-dwelling pools from the suction code. If that document is the correct one, 3" will be okay from that standpoint.
Ok, it looks like the 6 feet per second rule probably does not apply.
I suspect that the ANSI/APSP/ICC-5 2011 probably does apply as it is usually adopted into building code.
This gives you 184 GPM at 8 feet per second.
I think that there is maybe a 10%, or less, chance that it will cavitate at full RPM of 3,450.
If it does, you can back the speed down until the cavitation stops.
You might find that the maximum speed that you can run the pump is 3,150 or 3,000 RPM, which is still plenty of flow.
I suspect that the ANSI/APSP/ICC-5 2011 probably does apply as it is usually adopted into building code.
This gives you 184 GPM at 8 feet per second.
I think that there is maybe a 10%, or less, chance that it will cavitate at full RPM of 3,450.
If it does, you can back the speed down until the cavitation stops.
You might find that the maximum speed that you can run the pump is 3,150 or 3,000 RPM, which is still plenty of flow.
The maximum full runout pump flow is about 220 GPM at about 19 feet of head loss.
For 3" PVC pipe, that's 13 feet of head loss assuming 75 feet of PVC pipe and (6) 90s for 120 feet total equivalent length.
The velocity will be 9.72 feet per second.
Add on 3 feet of static head loss for a total of 16 feet of suction side head loss.
So, most likely, the pump will be able to get to full speed without cavitating.
www.engineeringtoolbox.com
For 3" PVC pipe, that's 13 feet of head loss assuming 75 feet of PVC pipe and (6) 90s for 120 feet total equivalent length.
The velocity will be 9.72 feet per second.
Add on 3 feet of static head loss for a total of 16 feet of suction side head loss.
So, most likely, the pump will be able to get to full speed without cavitating.
Hazen-Williams Water Flow Formula: Head Loss, Data, Charts & Calculator
Friction head loss (<i>ft<sub>H2O</sub> per 100 ft pipe</i>) in water pipes can be estimated with the empirical Hazen-Williams equation.
www.engineeringtoolbox.com
In this video, the cavitation begins at about -14" of mercury, which is about 16 feet of head, so it's possible that you could hit cavitation at full pump speed.
34 feet -16 feet = 18 feet of Net Positive Suction Head available.
The pressure required at the impeller is specific to the pump and you would need to know the Net Positive Suction Head Required for the IntelliFlo XF at full flow.
34 feet -16 feet = 18 feet of Net Positive Suction Head available.
The pressure required at the impeller is specific to the pump and you would need to know the Net Positive Suction Head Required for the IntelliFlo XF at full flow.
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- Dec 14, 2021
- 288
- Pool Size
- 24000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-60
Per PB: It is recommended by ANSI/APSP 7 Standards for Suction Entrapment Avoidance –that residential pools water velocity not exceed 8 ft per second.