IntelliFloXF Flow Issues

[andyoi630]

Ok, so a few updates.

After allowing the new pump to run overnight, I can now see speeds up to 70-72 GPM, which I don't believe I've ever seen before. It appears that after running for awhile, flows go up - maybe air working its way out of the system?

At full speed, the pump basket does completely fill with water (after some bit of time). At lower speeds (under 2000), I have noticed it only about half full.

The pump has a pressure reading of 39 PSI.

I took apart the previous pump. I don't see any signs at all of clogs in the impeller. Seems clean as can be.

Some pics below:

Return manifold:
In this picture, the spa has 2 lines (valved) up on the right by the wall. At the bottom is the start of the pool returns. The Intellivalve on the left switches between pool returns and In Floor system.

 

[ajw22]

70-80 GPM is the max flow I expect from a typical system with a large filter and heater.

 

[mas985]

39 PSI is equivalent to 90' of head loss so double what you originally calculated. That amount of head loss is consistent with the low flow rates that you are seeing. But that is far more head loss than I would expect from that plumbing design. With 21 PSI on the pressure side, that means there is almost as much head loss on the suction side as the return side which is not normal. Especially for the pipe size you have. Something is really restricting the suction side plumbing.

But I can't really tell much from the pictures. You wouldn't have a schematic that you could share would you?

BTW, the pump second from the right has the valve completely shut off. Not sure why that would be but make sure you never turn on a pump with the suction valves shut off like that.

 

[andyoi630]

Well that certainly helps, to narrow it down to a suction issue. I just don't quite understand, because it happens regardless of whether I pull from Skimmers, Main Drain, or combination.

Schematic here. Yes, I know it's absurdly complicated.

On the closed valve, I took the picture right before swapping pumps - I was about to pull that one. It's the spa jet pump, and below the level of the spa, so it would have drained out.

Thank you again for all of the help so far!!

 

[mas985]

The A&A LeafVac would be the first suspect. Have you cleaned that out and inspected it for any defects?

 

[andyoi630]

That would logically make sense. I clean it out every day or two basically. Any thoughts of what to look for for defects?

Going to run a couple tests this afternoon checking that pump psi readout by switching from pool drain, to skimmers, to spa drain. If all are the same, that almost certainly points to LeafVac. I just…don’t know why.

 

[mas985]

There might be something stuck in the line going into the vac. There are size transitions there that can plug up especially when the inlet is transitioning from 3".

Not sure why you have that anyway. The pump basket should be more than sufficient.

[EDIT] One more thing, the suction side valve right before the leaf filter could also be the cause if it is not in the correct position.

 

[andyoi630]

So I did some scoping with my camera scope - I see zero signs of blockage in any of the valves leading to the pump, or the leaf vac and its plumbing.

39 PSI holds constant where suction is coming from skimmers, pool drain, spa drain, or any combination of those. Sure does point to the leafVac being the problem?

 

[mas985]

Did you also scope the line between tha vac and the pump?

Also, are you sure the valve setting is correct?

 

[andyoi630]

Did you also scope the line between tha vac and the pump?

Also, are you sure the valve setting is correct?

Yes I did. Seemingly all clear.

And yes, have valves wide open.

 

[mas985]

There is a large head loss between the pool and the filter. It could be between the pump and the filter or before the pump on the suction side. But either way, the measurement data indicates a problem.

If you have a pressure gauge and/or a suction gauge, you can confirm the other measurements. A suction gauge on the suction side pump drain plug would show the suction side head loss. A pressure gauge on the pump return side drain plug will show the head loss from the pump forward.

BTW, when the pump shuts off, does the filter pressure gauge go to zero? Just want to make sure that is reading correctly.

 

[andyoi630]

There is a large head loss between the pool and the filter. It could be between the pump and the filter or before the pump on the suction side. But either way, the measurement data indicates a problem.

If you have a pressure gauge and/or a suction gauge, you can confirm the other measurements. A suction gauge on the suction side pump drain plug would show the suction side head loss. A pressure gauge on the pump return side drain plug will show the head loss from the pump forward.

BTW, when the pump shuts off, does the filter pressure gauge go to zero? Just want to make sure that is reading correctly.

Going to get a suction gauge to check these.

And yes, the filter gauge drops to 0 when the pump is off.

 

[andyoi630]

Ok, so I hooked up a vacuum/pressure gauge to the two drain ports on the filter pump.

In the furtherest forward port, near the suction entrance, I read -4 inHg. In the next port, I am actually off the scale of the gauge I had, but it seems to confirm the 39 psi that the pump controller reports (roughly). I believe both the controller and this port are measuring the outlet pressure? Am I understanding these correctly?

Questions -
1. The filter gauge is measuring the inlet pressure to the filter? This is equivalent to the return side pressure drop, correct? (Because the pool outlet pressure is 0).
2. Based on what you said before, I interpreted the 39 psi the pump reads to the be the sum of the return side pressure drop and the suction side pressure drop, is this correct?
3. I'm not understanding how the -4 inHg (2 psi) adds up with the 21 psi from filter to get to 39 psi?
4. I'm also not understanding how the 39 psi reading from the pump does not change, even if the filter pressure climbs some due to getting dirtier. For example, when we started this discussion, filter read ~21 psi. It reads about 23 psi now, but the pump still reads 39 psi.

Any ideas?

Suction side pressure:

Outlet pressure:

Pump reading:

Filter reading:

 

[mas985]

These measurements indicate very high head loss between the pump and the filter.

Suction head loss = 4.5'
Pump total head loss (suction + return) = 90'
Filter forward head loss = 48.5'

Head loss between pump and filter gauge = 90 - 48.5 - 4.5 = 37'

The pipe between the pump and filter should not have that much head loss. The filter gauge measures the pressure in the tank before the filter media. So that head loss is somewhere between the pump and the filter tank. From the schematic, it is only a pipe and a valve so it should have very little head loss.

 

[andyoi630]

Thank you. Have been doing similar analysis and came to the same conclusion. I am utterly stumped. It is just a single pipe and dumb valve between the pump and filter. I am at a loss.

 

[mas985]

Is that a pipe you have scoped? It looks like it is connected with unions so should be easy to remove to check out. Also, you might look inside the filter housing to see if there is anything obvious going on.

If the filter gauge is not reading correctly, then it could be something further down the line. You could check it by temporarily replacing the filter gauge with the other gauge that you used for the pump to see if it reads the same.

 

[andyoi630]

Well, I took that section of pipe out from the unions and scoped. It’s perfectly clear. Took apart the new pump and the impeller is completely clear, although I see a little damage to a black housing in the wet end of the pump.

Next I’ll swap the filter gauges to double check that pressure. I’ll check inside the filter as well, but Ive done that many times. But otherwise I am utterly out of ideas.

 

[andyoi630]

Swapped gauges on filter. New one reads maybe 1-2 psi higher. So, small discrepancy there. I feel like I’ve checked everything…

 

[mas985]

The measurements indicate a problem somewhere between the pump and the filter gauge. It is just a matter of figuring out what it might be.

What is that valve used for between the pump and filter? Are you sure that is in the proper position?

Also, I just looked at your pics again and that pipe between the pump and filter looks very narrow. Is that a 1.5" or even smaller pipe?

 

[andyoi630]

The measurements indicate a problem somewhere between the pump and the filter gauge. It is just a matter of figuring out what it might be.

What is that valve used for between the pump and filter? Are you sure that is in the proper position?

Also, I just looked at your pics again and that pipe between the pump and filter looks very narrow. Is that a 1.5" or even smaller pipe?

It’s a 2” pipe, only part of the main floor that is that small - I replumbed the filter outlet side to 3” last fall. I think it looks small because everything else is 3”.

I’ll just go ahead and replumb it. The valve I guess was installed by plumbers to have a filter bypass but was never really used. It’s a convenient was to stop filter from draining for quick pump maintenance though. It is in the right position.