Intelliflo VSF / Plumbing flow rate question

[JulianCaesar]

Hi,

I bought a house with a pool back in Feb., and had a heater and control system added to it. The current system has: Intelliflo VSF (3.95 THP), Clean & Clear Plus 320 sq ft filter, MasterTemp 400 heater, IC40 SWG, Intellicenter i8PSIC40.

I see that the IC40 requires 20 gpm (+/- 5 gpm) to function and the MasterTemp owners manual lists a minimum of 40 gpm and maximum of 120 gpm for the 400 model. My pool is about 20,000 gallons. The equipment pad is less than 10 feet away and the ground is pretty flat.

These are the flow rates according to the Intelliflo that I am getting:

RPM	GPM	Watts
2000	14	323
2300	21	508
3000	39	1192
3200	45	1479
3450	54	1897

Do these seem really bad? The SWG gives a flow error until I reach about 2100 RPM, so that flow rate seems in line with what the pump is saying.
The pool builder checked the filter and said it was clean and that the PSI seeemed normal. I think the PSI was about 12 at 2000 rpm and maybe 20 at 3000 rpm, but I could be remembering wrong.

It seems strange that it has to be nearly 500W just to run the SWG, which I was intending to just leave running all the time.

 

[JulianCaesar]

This is how the plumbing looks. The Intellicenter panel is just out of view.

 

[mas985]

Hi,

I bought a house with a pool back in Feb., and had a heater and control system added to it. The current system has: Intelliflo VSF (3.95 THP), Clean & Clear Plus 320 sq ft filter, MasterTemp 400 heater, IC40 SWG, Intellicenter i8PSIC40.

I see that the IC40 requires 20 gpm (+/- 5 gpm) to function and the MasterTemp owners manual lists a minimum of 40 gpm and maximum of 120 gpm for the 400 model. My pool is about 20,000 gallons. The equipment pad is less than 10 feet away and the ground is pretty flat.

These are the flow rates according to the Intelliflo that I am getting:

RPM	GPM	Watts
2000	14	323
2300	21	508
3000	39	1192
3200	45	1479
3450	54	1897

Do these seem really bad?

They aren't great. This would imply a plumbing curve of:

Head(ft) = 0.276 * GPM^2 which is worse than a typical 1.5" plumbing setup.

The SWG gives a flow error until I reach about 2100 RPM, so that flow rate seems in line with what the pump is saying.
The pool builder checked the filter and said it was clean and that the PSI seeemed normal. I think the PSI was about 12 at 2000 rpm and maybe 20 at 3000 rpm, but I could be remembering wrong.

It seems strange that it has to be nearly 500W just to run the SWG, which I was intending to just leave running all the time.

Heaters are often the culprit. Could be a broken bypass. What is the model # of your heater?

The cartridge filter is probably not the issue but what is the filter pressure at full speed?

How many returns are there in the pool and what size opening do they have?

Your setup is fairly simple so other than the returns and the heater, there is not much else that could cause that type of head loss unless you have a collapsed pipe underground or the underground plumbing is smaller than 1.5" diameter. The above ground looks to be 2" is that correct?

 

[pjt]

• You would benefit from an external heater bypass.
• The check valve between the heater and SWCG isn't needed.
• You should have 12" to 18" of straight pipe before the SWCG for optimal flow sensing
• A larger size cartridge filter would help
• What does your suction side plumbing look like?
• Clogged filters might be causing a flow restriction. Remove the cartridges temporarily and see what difference that makes.

 

[JamesW]

Pull the cell and make sure that it is clean.

Can you post the filter pressure at each speed?

 

[ajw22]

@pjt makes a lot of good suggestions.

The external bypass should be automatic and controlled by your IntelliCenter. See https://www.pentair.com/content/dam...heater_auto_bypass_valve_replacement _kit.pdf

My system needs 1700 rpm to make my IC60 happy and at least 2400 RPM for my MasterTemp heater flow.