Intelliflo XF VSF Readings Inaccurate?

Jump to latest Follow Reply
A

andyoi630

0
Aug 30, 2013
151
Maryland
So recently started up my new pool. Have 2 IntellifloXF VSFs and 2 VSs.

The GPM readouts I'm seeing from the pumps do not make any sense to me based on the pump curves.

For example, my Spa booster pump is showing approximately 11 psi on a manual gauge on return side - that should be about 23 ft of head right? At 3450 RPM, according to the curve, that should be about 210 GPM. Except, the pump readout is about 85 GPM. In that loop, there is a 3" suction, and a 3" and 2" return line. No filters/heater in that loop.

Filter pump is similar - Filter shows 19 psi at 3450 RPM, so 44 ft of head - that should be about 180 GPM. Nope - pump shows 70 tops. 3" drain suction + 2x 2" skimmer suction and 9x 1.5" returns + 2x 2" returns (each jet individually plumbed).

Are these readouts horribly inaccurate? Or do I have some other problem?
 
The return side/filter pressure gauges are only showing the return side pressure. The total tdh as per the pump curves is the return side pressure *plus* the suction side pressure.

The pump display has a readout of the total system psi (suction plus return). This value should always be larger than the filter pressure gauge psi, as it is including the suction pressure as well.
 
From the pump display, check power (watts), system pressure (psi), and flow (gpm) at 3,450 rpm.

If you have automation, put it in Service mode so that you can control the pump from the pump controller.

 
Ok thank you! So that makes a lot more sense. The spa pump reads 37 psi and filter pump reads 39 psi when each are at 3450 RPM. So the GPM numbers are consistent with those head numbers.
Now the question becomes, why are they so high? The spa pump I would expect to be MUCH lower than the filter pump, as it is basically just wide open 3” piping.
Filter pump is only 2 psi more, and going through loads more valves, filter and 2 heaters.
 

See the pump curve in the above reference. It shows power vs flow.

That's how it's getting the flow, and it's calculating the head loss from there.

It's not super accurate.

I would check the suction side pressure with a vacuum gauge.

That should give you the total system pressure/head loss.

Maybe there's an issue on the suction side and maybe the flow/psi reading from the pump is not accurate.

A clogged impeller can also cause inaccuracies in the readings.
 
Last edited:
Thank you all for the feedback. I guess I'm just stumped why my head loss is so freaking high.

Main filter pump has 3" suction from Main Drain, 2x 2" suction from skimmers, 10 individually plumbed returns. Full speed when going through (clean) filter and heaters, I can only get ~74 GPM. That means I can't even properly drive my in floor system.

Spa booster even seems odder. 3" suction, 3" return and 2" return, and maxes out at 95 GPM - no filters/heaters in the lines.

Do you guys have any thoughts? I expected IntelliFloXFs to push far more than this.
 
I wouldn't rely too much on the pump gpm readout.

It might not be very accurate.

I would check the suction side pressure and install a flow meter to verify what the pump is saying.

Maybe check the impeller that see if it's clogged.
 
You must log in or register to reply here.
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.
Top Bottom
Back
Jump to latest Follow Reply