Also Known As: Flow Meter

A flow meter is a device that measures the pool’s flow rate, or the rate at which the pool water is circulated through the filtering system back to the pool or spa. The flow meter is positioned on the water return pipe to the pool or spa.

The flowmeter must be located on a longer section of straight pipe in order to properly measure the flow rate. That means it cannot be positioned near any 90 degree turns in the pipe. The proper location would allow for two times the pipe diameter to be in front of the flow meter and four times the pipe diameter behind the flowmeter. For example, a flowmeter mounted on 4-inch pipe would need 8 inches of pipe in front of it and 16 inches of pipe behind it. The flow meter must match the pipe diameter it is mounted on.

The least expensive and most common flow meter used in swimming pools is installed on the plumbing itself. A pitot tube is inserted perpendicular to the pipe, via a small hole. The flow rate is calculated by measuring the water passing through the flow meter and displayed on an analog or digital reader. Most flowmeters have a bobbin that is pushed up. Identifier rates are notated on the side of the meter. Digital readers require some sort of power source, either battery or electric. These are typically saddle mounts, which house the pitot tube and sit on top of the plumbing.

Flow meters must be maintained regularly, by cleaning out sand or particles trapped in the pitot tube that prevent the bobbin from flowing freely.