Water Flow and Pressure

Flow.
A rate of flow can normally be worked out by the volume of water that will flow in a period of time. A simple example of this is as follows, a 2ltr bucket takes 2seconds to fill, the flow rate will be calculated at 2litres per second.

Pressure:
A cold-water storage cistern fitted in the loft of a house is an excellent example of pressure. It feeds outlets upstairs and downstairs. The pressure at a downstairs outlet will be higher as the distance is greater to feed, rather than the bathroom sink upstairs, because the distance is shorter and the height is not as steep. This is all relative to the height of the cylinder. Opening the nozzle slightly on a garden hose, a really high jet of pressure can be seen. Now open the nozzle fully and the pressure will be much less, however, the amount of water coming out (its rate of flow) will be bigger. Devices are available on the market that can measure this type of pressure and flow. A professional plumber from Greenwich Plumbers will use them. If a new plumbing installation is being planned, the incoming water and flow may be needed to help with the design.

Pressure Gauge:
The mains gauge will give an accurate pressure reading for the supply to a service. It is connected using a standard plumbing thread.

The Weir Cup:
This device is designed and used to take flow rate readings and will be carried by all plumbing professionals. It reads both litres per second and gallons per minute. Should the rate of flow in a system need reducing the weir cup can be used to measure, then accurately adjust the flow rate to meet the rate required to suit an appliance’s recommended operating specification. A professional installer like a Greenwich Plumber may need to check there is a sufficient flow rate for a condensing boiler.
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