PVC size for small pool: No such thing as too big?

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M

Myburneraccount

Well-known member
Apr 12, 2022
52
Dallas
Pool Size
10000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Jandy Truclear / Ei
So I'm going down the rabbit hole of PVC and plumbing.

Initially I thought asking for a minimum of 2" PVC was upgrading efficiency but now I'm seeing that 2 should be minimum and 2.5 to 3" is the true upgrade.

For a small pool (11,000 gallons, 13x28 incl 7x7 spa, 4-5.5 deep), is there such thing as going too big? If the filter can all handle flow up to 140gpm and my PB oversold me on a VS 2.7hp pump, would it be worth any additional cost to go from 2" to 2.5" or even 3.0"? Is there such thing as too much flow rate without any special water features and only 5 spa jets on a spill over? Could having larger pipes on the spa suction, and thus more flow, result in any undesirable results? Should the pipes be a size larger on suction vs discharge or all the same?

So many answers on this forum but the deeper I go down the rabbit hole, the more confused I get.

Thank you.
 
On the suction side of the pump the pipe should be the same as the pump inlet or one size larger.
The Hayward Tristar 950 (2.7HP) inlet can handle a 2" or 2.5" pipe.
I have 2" piped to this pump. Pool is 17800 gallons, no spa. Have no issues.
At 3450 RPM the flow rate is 115GPM @ 10 PSI uses 2.4 KW per hour.
At 1550 RPM the flow rate is 55GPM @ 2 PSI uses 240 watts/hour.

Larger pipe has less friction loss moving the same amount of water as a smaller pipe. Less friction means less power to move the same amount of water.
Larger pipe carries more water at the same friction loss of a smaller pipe.

You can go to big as it can effect the skimmer. Above 60 GPM the skimmer can pull air if the water level is less than 1/2 the height of the skimmer opening.
With 2" pipe, get 2 skimmers.
 
AQUA~HOLICS said:
This is plumbing for a 15,000 gallon pool and spa, 3” for spa, 3” for booster and water features, 2 1/2“ for pool pump (VFP).
Click to expand...
Thank you. For clarification the 3" on spa is on suction, discharge, or both? 2.5" is coming from the main drain and skimmer? Are the return lines the same?
 
BMerrill said:
On the suction side of the pump the pipe should be the same as the pump inlet or one size larger.
The Hayward Tristar 950 (2.7HP) inlet can handle a 2" or 2.5" pipe.
I have 2" piped to this pump. Pool is 17800 gallons, no spa. Have no issues.
At 3450 RPM the flow rate is 115GPM @ 10 PSI uses 2.4 KW per hour.
At 1550 RPM the flow rate is 55GPM @ 2 PSI uses 240 watts/hour.

Larger pipe has less friction loss moving the same amount of water as a smaller pipe. Less friction means less power to move the same amount of water.
Larger pipe carries more water at the same friction loss of a smaller pipe.

You can go to big as it can effect the skimmer. Above 60 GPM the skimmer can pull air if the water level is less than 1/2 the height of the skimmer opening.
With 2" pipe, get 2 skimmers.
Click to expand...
I will have a jandy epump 2.7hp and i believe it can handle 2-3". How long do you run your pump for and at what rpm?

Is 2 skimmers necessary if the pool portion of my pool is 13x19 not including spa and baja?

Thank you.
 
For suction, you want to keep the water velocity below 6 ft/sec. For returns, you want to keep the water velocity below 8 ft/sec.

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
 
JamesW said:
For suction, you want to keep the water velocity below 6 ft/sec. For returns, you want to keep the water velocity below 8 ft/sec.

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
Click to expand...
An extreme (or not so extreme) example... If I run 3.0" and get a flow rate of 138/184gpm... is that overkill on my 11,000 gallon pool?
 
Myburneraccount said:
An extreme (or not so extreme) example... If I run 3.0" and get a flow rate of 138/184gpm... is that overkill on my 11,000 gallon pool?
Click to expand...
You have to decide why you want flow.

For filtration, jets, heating or what?

Each purpose has a different flow rate that would best suit the need.
Filtration or operating a SWG can be done at about 20 gpm.

Heaters require a minimum as defined in the heater manual.

Spa Jets are based on the flow per jet x the number of jets.
 

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JamesW said:
You have to decide why you want flow.

For filtration, jets, heating or what?

Each purpose has a different flow rate that would best suit the need.
Filtration or operating a SWG can be done at about 20 gpm.

Heaters require a minimum as defined in the heater manual.

Spa Jets are based on the flow per jet x the number of jets.
Click to expand...
I don't think my flow requirements are too high. Have a jandy 400k heater and jandy chlorinator. Filter is 150gpm max i believe. Max flow would be spa with 5 jets and judging by how the PB is building this pool, I assume I'm getting stardard jets (5) to max around 15-18gpm each.

My main goal is energy efficiency. I live in CA and don't have solar yet to offset any electricity. Also, if I can get away with running the pump at a lower RPM that would be ideal for noise alone. I know that my pool pump is likely oversized and that's a source of energy inefficiency but I'll tackle that issue separately.
 
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