Can I have two 2" lines connected to 1 pump?

[johnkim2020]

I have a 3HP pentair VSP. According to this slide, 2" line max flow is 63gpm - 84gpm: https://hayward-pool-assets.com/ass...draulicPumpSizingDiagnostics.pdf?fromCDN=true

3HP pentair does 120gpm at full speed with 70' head: https://www.pentair.com/content/dam...iflo-variable-speed-pump-brochure-english.pdf

Can I plumb two 2" lines to take advantage of the full power of 3HP pump?

 

[cowboycasey]

I have 2, 2 inch on mine right now and will have 3, 2.5 inch on my new pool

 

[mas985]

I have a 3HP pentair VSP. According to this slide, 2" line max flow is 63gpm - 84gpm: https://hayward-pool-assets.com/ass...draulicPumpSizingDiagnostics.pdf?fromCDN=true

3HP pentair does 120gpm at full speed with 70' head: https://www.pentair.com/content/dam...iflo-variable-speed-pump-brochure-english.pdf

Can I plumb two 2" lines to take advantage of the full power of 3HP pump?

Just to be clear, those are NOT maximum flow rates. Those are simply recommended maximum flow rates meaning that the flow can and will exceed those values under certain conditions. Also, exceeding those flow rates does not have any catastrophic consequences. Just more head loss.

Having said that, with a VS pump, you shouldn't be operating at anywhere near those flow rates unless you are trying to run a high flow rate water feature (spa, waterfall, etc) but then you should be using much larger pipe. Otherwise, there is not much reason to operate more than about 30 GPM.

 

[johnkim2020]

Just to be clear, those are NOT maximum flow rates. Those are simply recommended maximum flow rates meaning that the flow can and will exceed those values under certain conditions. Also, exceeding those flow rates does not have any catastrophic consequences. Just more head loss.

Having said that, with a VS pump, you shouldn't be operating at anywhere near those flow rates unless you are trying to run a high flow rate water feature (spa, waterfall, etc) but then you should be using much larger pipe. Otherwise, there is not much reason to operate more than about 30 GPM.

Thanks.

I will be operating one waterfall(unknown GPH) and one sheer descent (~3000GPH).

My pool technician tells me I need another pump for those features and just keep the 3hp for normal pool circulation because 2" intake is not large enough for 3hp...

It doesn't make sense to me to use 3hp for normal circulation so why not feed two 2" suction to my 3hp pump to power my water fall and water feature and normal pool return?

Pentair designed 3hp pump with 2" ports so why wouldn't 2" be able to deliver the max flow 120gpm at 70' head? I reckon 7200 gph is sufficient for my water features.

Any damage of running one VSF at full speed vs two pumps at reduced speed?

 

[mas985]

You can do what you are suggesting but there are a few consequences. Forcing high flow rates through a filter and heater is generally not a good idea for both energy efficiency as well as filters don't work as well at higher flow rates (i.e. water forces debris through the filter). Having a separate feature pump that does not go through these elements avoids this problem.

 

[johnkim2020]

You can do what you are suggesting but there are a few consequences. Forcing high flow rates through a filter and heater is generally not a good idea for both energy efficiency as well as filters don't work as well at higher flow rates (i.e. water forces debris through the filter). Having a separate feature pump that does not go through these elements avoids this problem.

Thanks.

I was reading that certain water feature like laminar jet and sheer descent need to have filtered water or else it will clogg those jets. Do I need two filters then?

Here are my setups if you have any advice:

1. hayward 30" sand filter max flow 98 gpm according to manual
2. four laminar jet ~ total 4000 GPH . Does laminar jet needs to have a fixed speed pump since VSP will change the arc trajectory?
3. One sheer descent 3000-4000 gph
4. One water wall unknown GPH similar like this :

5. 17000 GPH pool
6. Four spa jets with 1 hp dedicated pump

Pumps I have now:
1. 1HP fixed speed
2. 3hp VSP


Maybe I plumb 4 laminar, sheer descent, main pool circulation to 3hp and going through filter/heater and one extra pump for water curtain?

 

[mas985]

For laminars, it is definitely a good idea to have a filter but you need a high flow filter such as a 150 GPM cartridge. I would not use sand or DE for high flow rates as the backwash valves have high head loss.

If you want to use the same filter and same pump what you could do is have a valve after the filter (i.e. high flow rate cartrdige) but before the heater (assuming you have one) that branches the higher flow rates off to the features before it hits the heater. Automation with actuators is probably a must with this type of setup.

But what is each pump you have now used for?

#2 & #3 could very well exceed the limits of the pump and adding #4 will most definitely. You may need another large pump anyway.

 

[cowboycasey]

could you do #2 and #3 on 1 3hp vs and the pool and #4 on another 3hp vs setup? Would that require 2 cart filters, 1 for each setup?

The Pentair clean and clear plus is a great filter that can handle that GPM..

 

[johnkim2020]

For laminars, it is definitely a good idea to have a filter but you need a high flow filter such as a 150 GPM cartridge. I would not use sand or DE for high flow rates as the backwash valves have high head loss.

If you want to use the same filter and same pump what you could do is have a valve after the filter (i.e. high flow rate cartrdige) but before the heater (assuming you have one) that branches the higher flow rates off to the features before it hits the heater. Automation with actuators is probably a must with this type of setup.

But what is each pump you have now used for?

#2 & #3 could very well exceed the limits of the pump and adding #4 will most definitely. You may need another large pump anyway.

Thanks.

My pool is not operational yet but currently, 1 HP fixed is setup for spa jet.

I'm trying to decide what to do with the 3hp VSP.

If we do the 3way valve water the filter, the purpose with automation/actuator is to adjust the flow about how much water directly to water feature and how much to heater?

 

[mas985]

Two fold. You will need to shut off the waterfalls when heating the spa. Also, I assume you don't want to use the waterfalls when just filtering the pool and at much lower speeds to save energy. So you need a way to shut them off. But again, I don't think a single pump will be able to handle all of the water features.