IntelliFloXF Flow Issues

[andyoi630]

Hi All,

I started a similar discussion 2 years back, but since I've done more investigation and am hoping for a little more help if possible.

Completed my pool in early 2020, it's my second one. I have a pretty complicated setup, and I'm struggling substantially with my primary pump, an IntelliFloXF VSF. I have 4 of them, but the primary pump runs the pool, spa circulation, filtration, and In-Floor system. At my old pool, I had an IntelliFlo, and upgraded on this one to the XF due to the in-floor system (and similar cost). My XF is yielding lower flow rates than my old Intelliflo, with a better plumbed system this time around.

At *BEST* case, with a perfectly clean filter, at 3450 RPM, I will never see north of 65-67 GPM. 2000 RPM is only 25-30 GPM on a good day. I was previously used to be able to run my old chlorinator and spillway at 1600rpm with an Intelliflo, and I stand absolutely 0 chance of being able to do that with mine now. Typically, I need to be at 2700+ RPM to run heat or anything of substance, which seems absurd.

Some facts:

Suction side:
2x 2" lines from skimmers, plumbed home runs with 2" valve
1x 3" line from main drain, 3" valve between skimmers and drain
A&A LeafVac plumbed in with 45s and 3" lines into Pump.
All plumbing from drain line onwards is 3".

Pressure Side:
1x Pentair Quad DE 100 Filter (Rated for 160 GPM max flow)
Returns all home run plumbed with individual lines -
-- 2x 2" lines
-- 8x 1.5" lines
1x 3" Cleaner supply line (to 2x A&A 6 port valves)
2x 2" Lines to spa heat jets (2 sets of 3 jets)
Plumbing from pump to return manifolds is 3" lines, 3" Jandy valve

Things I've tried:
- Changing suction from skimmers to drain makes no difference
- Mixing skimmers and drain makes no difference
- No difference between sending flow to pool returns, or to cleaning system
- Flow increases negligibly if spa returns opened same time as cleaner and pool, but never above 67ish gpm.
- Examined every valve for blockages
- Swapped valves from 2" to 3" on return side

I'm literally at my wit's end. I can only run my in-floor system if the filters are in pristine condition, and not spectacularly at that. I can't run my system at low RPMs because the flow drops too low for the heat pump.

Is there any chance at all that the Quad DE filter or the LeafVac are creating massive restrictions? I had the Quad DE before with no issue, but never the LeafVac.

Thanks!

 

[ajw22]

Pump flow is inversely proportional to the system head. Your pump behavior says you have a very high head system no doubt due to a combination of your plumbing and all the gadgets you have on it.

I am sure your IFCS adds to the head when it is on.

You may have some blockage in a pipe that happened during construction or plastering that is adding restriction. To figure out the problem may take invasive experiments with your plumbing.

For example I would rig up PVC from the output of your filter or heater directly to the pool and see what flow you get. Work piece by piece down the system and see what flows you get and I think you will discover where it suddenly drops.

When theory is not working the way you expect you have to figure out where things are not as you think they are.

Post pics of your complex equipment and pool so we can see what you are dealing with.

@mas985 may have ideas.

 

[andyoi630]

Pump flow is inversely proportional to the system head. Your pump behavior says you have a very high head system no doubt due to a combination of your plumbing and all the gadgets you have on it.

I am sure your IFCS adds to the head when it is on.

You may have some blockage in a pipe that happened during construction or plastering that is adding restriction. To figure out the problem may take invasive experiments with your plumbing.

For example I would rig up PVC from the output of your filter or heater directly to the pool and see what flow you get. Work piece by piece down the system and see what flows you get and I think you will discover where it suddenly drops.

When theory is not working the way you expect you have to figure out where things are not as you think they are.

Post pics of your complex equipment and pool so we can see what you are dealing with.

@mas985 may have ideas.

Thank you, appreciate the thoughts. I will post some pictures later when I get home.

Yes, I believe my in floor adds head, but I don’t see any noticeable flow difference whether I have water going through it or not.

Agree with you that it’s something out of the norm -

Given that it happens with skimmers and domain drain, I don’t think it’s in the underground suction.

Given that it happens either to the cleaning system or pool returns (also since I have 10 return lines), I don’t think it’s in the underground return side either.

I’ve also replumbed every valve on the return side (at significant cost) to go to 3” valves, with no difference.

The only things I haven’t ruled out in my mind are the filter itself, or the LeafVac? I just find it really hard to believe either are the issue. Especially since I used that same filter before.

 

[ajw22]

The same filter is not the filter you have. Maybe you have a manufacturing defect in the filter?

You have to consider all possibilities and rule them out with experimentation one by one.

 

[mas985]

What is the filter pressure at full speed?

Pressure > 30 PSI is likely a return side problem. Pressure < 20 PSI is likely a suction side problem (i.e. clogged impeller).

FYI, the Intelliflo VS and the Intelliflo XF VS are not all that much different when attached to high head features such as IFCSs. The XF only produces more flow rate on very low head loss plumbing (i.e. has a flatter head curve but not higher).

 

[andyoi630]

What is the filter pressure at full speed?

Pressure > 30 PSI is likely a return side problem. Pressure < 20 PSI is likely a suction side problem (i.e. clogged impeller).

FYI, the Intelliflo VS and the Intelliflo XF VS are not all that much different when attached to high head features such as IFCSs. The XF only produces more flow rate on very low head loss plumbing (i.e. has a flatter head curve but not higher).

At full speed with a clean filter I’m sitting around 25 psi pushing flow through either the IFCS or the pool returns. That jumps to 30ish going to the spa jets, but that’s kind of expected.

I would have thought my system was a low head loss system for the standard pool returns. I’ve added up the head before for the piping, equivalent lengths for fittings, filter, heaters and valves, and should be seeing well over 100 gpm by my math and curve analysis.

 

[mas985]

How are you measuring flow rates?

Also, what are the lengths of the lines from pool to pump?

 

[Jimrahbe]

Andy,

I see you have a Quad DE 100 filter.

We have seen these plumbed with the wrong multiport valve before, so it might be worthwhile to check the MPV part number to make sure you have the correct MVP for your Quad 100.

Thanks,

Jim R.

 

[andyoi630]

How are you measuring flow rates?

Also, what are the lengths of the lines from pool to pump?

Using the VSFs calculation, which I understand is not perfect, but I can also very much see that I don’t have the flow my IFCS was specd for. A&A called for 84 GPM and saw no issue with that pump and a 3” line.

Total plumbing length is about 60 ft to drain.

 

[andyoi630]

Andy,

I see you have a Quad DE 100 filter.

We have seen these plumbed with the wrong multiport valve before, so it might be worthwhile to check the MPV part number to make sure you have the correct MVP for your Quad 100.

Thanks,

Jim R.

Hi Jim, I actually don’t have a MPV, I have my pump plumbed in straight to the filter.

 

[mas985]

25 PSI is a bit on the low side from what I would expect with that setup @ 3450 RPM. That equates to about 60' of head and since the suction side should have very little head loss, the XF should be pushing close to 160 GPM. Since this is not the case, it sounds like there may be an issue with the pump. More specifically, the impeller could be clogged. I would remove the wet end from the motor assembly and inspect the impeller vanes for any clogs.

 

[ajw22]

Since you said you have 4 XF pumps, can you swap pumps?

 

[andyoi630]

I have opened up the pump before to look for anything major but will give it another go and just swap the pumps. Shouldn’t be too hard. I have one other VSF and two other VSs.

And yes, that lines up with my head calculations. I believed I was in the 50-60 ft range when adding up everything, so I never imagined I’d have a flow issue.

The pump sounds very normal though, would you expect different noises?

The other VSF pump is for my spa jets. No other equipment in line, 3” suction, 3” and a 2” return (two zones). If I open all the jets to full open I see about 85 GPM. If I remove the jet orifices, maybe 110. Does that make sense? There would still be the internal jet bodies which I assume have restrictions from air mixing.

 

[mas985]

A clogged impeller may not make any noise at all. It will just retard flow rate.

How many spa jets are there and what size is the nozzle orifice?

And yes, that lines up with my head calculations. I believed I was in the 50-60 ft range when adding up everything, so I never imagined I’d have a flow issue.

Head loss is dependent on flow rate so what flow rate did you assume? In reality, both the pump and the plumbing have head curves that cross over one another at the operating point so you really can't determine one without the other. Did you first estimate the plumbing head curve and then plot that over the pump's head curve to find the operating point?

 

[andyoi630]

A clogged impeller may not make any noise at all. It will just retard flow rate.

How many spa jets are there and what size is the nozzle orifice?


Head loss is dependent on flow rate so what flow rate did you assume? In reality, both the pump and the plumbing have head curves that cross over one another at the operating point so you really can't determine one without the other. Did you first estimate the plumbing head curve and then plot that over the pump's head curve to find the operating point?

Suction piping (150 ft) @ 100 GPM in (4” equiv) pipe - ~2.5 ft
Return piping (150 ft) @ 100 GPM in (5” equiv) pipe - ~ 1 ft
Filter @ 100 GPM - 10 ft
Heat Pump (Raypak 8450) @ 30 GPM - 21 ft
Gas Heater (Raypak 406A) @ 30 GPM - 4 ft

So, at 100 GPM that’s 38.5 ft of head. Add a couple for valves. 40 ft of head should allow the XF to pump 200 GPM.

At 150 GPM, the filter is the main thing that changes (since heaters are valved for min required flow). Add about 8 ft of head for that. Brings the pump down to a theoretical 180 GPM.



Spa jets - I have 12 jets on that pump. Waterway poly storm. Unsure their orifice size.

 

[mas985]

So do the heaters have a bypass? Is that why the flow rate is less for that calculation? How is that configured.

I assume that the piping "length" includes the equivalent length of all 90s, 45s, tees but what about the other items such as valves, eyeballs, IFCS heads, skimmers, MD ports, etc. Every single item in the plumbing chain causes head loss. Nothing can be ignored.

Can you post a picture of the equipment pad?

But again, the first thing I would check is the impeller vanes.

 

[Toxophilite]

Maybe the longest of long shots, but is there any place in there among your complicated piping that could create an air trap in the system? Air traps can cause substantial head loss in fluid systems, but you would have to have a hard trap point somewhere to be the case.

 

[mas985]

Turbulent flow water will normally push air out of the way. It can only really collect in the tops of pump baskets or filters. In pressurized pool plumbing air can't retard flow rate.

Airlocks can only really prevent flow rate under siphon conditions.

 

[andyoi630]

Ok so, I had a chance to swap the pumps to the one next to it. There might have been the slighted improvement.

At 3450 RPM, new pump is running 60 GPM to in floor at 21 PSI filter pressure. —- Is this low like you were indicating before?

At 2000 RPM, 42 GPM.
At 1600 RPM, 30 GPM.

I have not had a chance to look at their impellers yet. And to answer the earlier question, yes I have a heater bypass.

Thoughts?

 

[mas985]

What does the pump drive display show for pump pressure?

Since you swapped pumps, it isn't likely to be the impeller but it could be something else on the suction side.

Is the pump basket completely filling with water?