VS Pump speed

JamesW

TFP Expert
Mar 2, 2011
28,250
Get a regular pressure gauge and screw it into the drain plug hole at the bottom of the heater manifold so that we can see what the pressure from the heater back to the pool is.

A flow meter is not too hard to install. Just drill a 5/8” hole in the pipe and clamp the meter into the pipe.

Flow meter model number required D-30200P.

2” vertical pipe with the flow going down.



D-300 = Vertical down flow


 

KevinBond

Well-known member
May 7, 2021
101
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
That is usually why we recommend finding your minimum rpms to close the flow switch with a clean filter and then add 200 or so.
Perfect, that was my plan. Do you use the flow switch turning off your SWG to determine when you need to backflush or still use the filter gauge?
It's a good idea to monitor your SWG to make sure no unexpected lights are on. I usually like to walk to my equipment pad and look at the controller once a day just to make sure everything is kosher.
Absolutely, I do this but just want to make sure if I miss a day and the flow rate is no longer activating the SWG this won't cause any problems.
 

KevinBond

Well-known member
May 7, 2021
101
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
Flow meter model number required D-30200P.
I think I get my hands on this one. 20-100GPM is ok? On the charts I created earlier, I had GPMs as low as 11. This flow meter won't be able to measure these. I see there is also a D30200PR that is 18-70 GPM.
What RPM does it take to operate the heater?
The manual says min 25GPM and my IntelliCenter has the heater circuit set to 30GPM. I'm not sure how to test the minimum RPM. Can I just set the circuit to an RPM known to activate the heater, turn it on, then turn down the RPM until the heater's water pressure switch turns it off? Is this safe to do?
 

JamesW

TFP Expert
Mar 2, 2011
28,250
You can use an ohmmeter on the pressure switch with the heater wires off and adjust the pump speed until the pressure switch opens or closes.
 

DeanP66

Well-known member
Mar 26, 2014
1,230
San Jose, CA
Perfect, that was my plan. Do you use the flow switch turning off your SWG to determine when you need to backflush or still use the filter gauge?
No, my cartridge filter never gets very dirty. I barely even look at the pressure gauge. I just usually clean it twice a year, once in early March and once at the end of the pool season in October. My pump basically runs 24/7 at 1100rpm and I never have an issue with flow.

Once in a while, I will turn the pump up to 2500rpm for 30 minutes just to drain my spa to get out any sediment. At low rpms, it just doesn't overflow much into the pool, so the water seems to stay somewhat stagnant and the dirt and dust accumulate on the bottom. When I get within a foot of the bottom, I'll close the spa drain and open the returns to the spa to fill it back up with clean filtered water.
 

JamesW

TFP Expert
Mar 2, 2011
28,250
If you can install a flowmeter on the horizontal section, you can get a flow switch attachment that you can use instead of the pressure switch.


1623439000337.png
 

KevinBond

Well-known member
May 7, 2021
101
Kitchener, Ontario, Canada
Pool Size
71000
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-40
If you can install a flowmeter on the horizontal section, you can get a flow switch attachment that you can use instead of the pressure switch.
Interesting, but when I was reading up on the horizontal flow meters, it didn't sound like it would work for my setup (there isn't enough of a horizontal stretch of pipe between my filter and heater).
 

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JamesW

TFP Expert
Mar 2, 2011
28,250
You would need 10 inches before and 4 inches after.

Do you have room to put it at the "F"?

InkedKevin Bond System Flow Meter_LI.jpg

Even if the inlet isn't exactly 10 inches, it will probably still work.

It might affect the accuracy a little bit, but probably not too much.

You probably don't need the flow switch part, so the vertical install should be oK.



1623439916170.png
 

JamesW

TFP Expert
Mar 2, 2011
28,250
Be careful when drilling the hole for the flow meter.

Don't allow the pvc debris to get into the pipe going to the heater because it can get stuck in the heater's internal bypass.

There are two unions that you can undo to get the section of pipe out if any debris gets in the pipe.
 
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needsajet

TFP Expert
LifeTime Supporter
Jan 4, 2016
4,955
Sydney, NSW, Australia
Pool Size
44000
Surface
Plaster
Chlorine
Salt Water Generator
Re: drilling pipe.

I'd recommend you mark the spot where you want the gauge. Consider a position for it to end up being out of the way but still readable. If it were mine, I'd plan it to extend backward toward the brick alongside the filter, as long as the reading side would be facing out. Take that section of pipe off by undoing the unions, so you can work on it out in the open.

I've had good success by starting with a 2 mm or 1/16" pilot hole in the spot I want. Then when drilling the full size hole, run the drill in reverse with a bit of pressure and let the heat remove the plastic. I'd probably do a 1/4" or 3/8" second pilot hole before the final 5/8" hole. That way the drill bit can't grab suddenly and crack the pipe. Once through, rock and rotate the drill to make the debris fall off, or use a small file, or a hook of some sort, and shake out the debris. You can also run some water through the pipe section by dipping it repeatedly in the pool.
 
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