How To Install a Pool Water Flowmeter


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A Flowmeter measures the actual flow of water through your recirculation system. These meters are calibrated to the size of your piping - e.g. if you have 1 1/2 piping you would purchase a 1 1/2 inch Flowmeter; for 2" piping, a 2-inch Flowmeter, etc. This 1 1/2" Flowmeter will measure between 20-75 Gallons Per Minute (GPM). This guide shows you how to install a Flowmeter on the discharge side of a 1 1/2" pipe system.

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Step by Step


Step 1

CHECK YOUR PARTS - For a 1 1/2" pipe, we will be installing the 1 1/2" Flowmeter, F30150P. The F300 series mounts on horizontal pipes. The D300 and U300 series mount on verticals pipes. Other parts include: 2 stainless steel clamps, a gasket and two screws. Make sure you order the Flowmeter for PVC pipe and not copper - The part number will end in "P" or "PR".

Step 2

TURN OFF POWER TO THE PUMP at the circuit breaker.

Step 3

RELIEVE WATER PRESSURE at the relief valve on top of the filter.

Step 4

SELECT AN INSTALLATION SITE - provide a minimum of 8" clearance above the pipe for the Flowmeter. Also the pipe on which the Flowmeter is installed has to be horizontal and 21" long - 6" after the Flowmeter and 15" before the Flowmeter. Install the Flowmeter after the filter. Avoid placing it right after a point where you inject chemicals like chlorine or acid.

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Step 5

LOCATE THE CENTER OF THE HOLE for the Flowmeter. The hole will be in the top of the pipe at a point that provides 15" of straight pipe before the Flowmeter from where the water is coming and 6" of straight pipe after the Flowmeter to where the water returns.

Step 6

DRILL A PILOT HOLE with an 1/8" drill bit to center the larger drill.

Step 7

DRILL A 5/8" HOLE. The Flowmeter must be installed straight up and down within 2 degrees.

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Step 8

REMOVE ALL BURRS around the hole with a round file.

Step 9

INSERT THE PITOT INTO THE HOLE. Make sure the gasket is in place and that the pitot tube opening faces into the direction of flow.

Step 10

PLACE THE CLAMPS on either side of the Flowmeter as shown and tighten the clamps alternately, a little at a time. As you tighten the clamps, make sure the Flowmeter is straight up and down.

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Step 11

CHECK THAT FLOWMETER IS STRAIGHT UP AND DOWN WITH A LEVEL. Snug down the clamps but do not overtighten.

Step 12


Step 13

CLOSE OFF THE RELIEF VALVE after water begins to spray out.

Step 14

READ THE FLOWMETER at the top of the float

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(1 to 8 of 8)

 Posted: 8/27/2021 

What if my horizontal pipe isn't level. It is probably 3 1/2 feet long and 2 inches higher on one end

InyoPools Product Specialist  Posted: 9/1/2021 

That shouldn't have too much of an effect on the flowmeter. But I would reference the plumbing instructions in the owner's manual of your specific flowmeter. There's an exception to every rule, so it is always best to doublecheck the manual

Anonymous  Posted: 12/4/2017 

If my piping is 2" from pump and to and from the filter but reduces to 1 1/2 at a diverter that goes to pool jets and spa jets, what size flow meter do I use?

InyoPools Product Specialist  Posted: 9/11/2016 

Flowmeter text errors - Thank you for your editing. I made the corrections to the text.

Anonymous  Posted: 9/9/2016 

Text indicates 15 feet not inches - graphic uses " inches.

 Posted: 4/12/2014 

Thanks I'm about to replace a flowmeter on a 2" so the information gave me the correct steps to take to make it easier.

Anonymous  Posted: 12/18/2013 

Good article...I give it 5 stars...I'm about to purchase one

Anonymous  Posted: 8/6/2012 

Rating should still be 5 stars. I accidentally hit wrong key. Great instructions for a novice!