Pressure and Flow

Mains Water Pressure Gauge.

The mains gauge is used to give an accurate pressure reading for the mains supply to a service. It connects via a standard plumbing thread.

Weir Cup.

A piece of equipment exists called a weir cup. The weir cup is used to get accurate flow readings and is part of a plumbers kit. It will read both litres per second and gallons per minute. If the flow rate of a system needs to be reduced, a weir cup may be used to measure and then accurately adjust the flow rate to meet the operating flow rate required to suit an appliance’s recommended specification. A professional installer like a Lewisham Plumber may need to check there is a sufficient flow rate for a condensing boiler.

Flow.
Is defined as how much water is delivered over a set period of time. For example if a 20ltr bucket takes 20 seconds to fill then the flow rate is 1 litre per second.

Water Pressure.

A good example to give, regarding pressure is a cold water storage cistern that supplies water to a sink in a bathroom upstairs and a sink in a downstairs WC. The pressure downstairs is higher than upstairs due to the position (height) of the sink and the tank.

With the nozzle open slightly on a hose, there is a really high pressure jet coming out. Once the nozzle is open fully, the pressure will be far less but the amount of water coming out (rate of flow) will be larger. There are Devices are on the market that measure pressure and flow. You will see a professional plumber from Lewisham Plumbers using these. When a new plumbing installation is planned the measurements of both the incoming water and flow may be needed to help with the design.

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