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Safety valves in hot water systems

Incidents of scalding caused by hot water are on the rise, but there are ways to minimise this risk, including tempering valves and thermostatic mixing valves. Here, Richard Bateman, product marketing manager at RWC UK, looks at the issues and the solutions, giving tips about correct installation and maintenance


s plumbing and heating installers, we’re all aware of the dangers of legionella, and the need to maintain water temperatures around 60-70°C in order to kill it off. While this solves the bacterial health risk, it also gives rise to another hazard – scalding. Burns caused by hot water from taps is rising steadily according to NHS data, and bath water scalds are rated as one of the most painful experiences that can be endured.

A number of factors might be contributing to this rise, not least the lockdowns which mean we’re all spending more time at home. But even before COVID- 19, there had been a big increase in multigenerational dwellings, with families looking after older relatives. Equally, there’s been a big rise in

Richard Bateman, product marketing manager at RWC UK

multi-occupancy buildings – such as for students, which rely on pressurised cylinders to deliver a sufficient supply of hot water.

Although these cylinders have fail-safe mechanisms including expansion vessels, thermal valves and pressure relief valves, they’re still subject to poor installation, maintenance and potential component failure. Moreover, while these protect the cylinder, they can’t prevent the water heating to dangerous temperatures long before the safety devices kick-in.

Hot water splash back, from a basin or sink, could potentially cause serious scalding injuries in less than three seconds – especially concerning for children who burn more easily. There are

Tempering valves and thermostatic mixing valves (TMVs) are effective solutions to the problem of scalding

Brand NEW Velocity range The Velocity cold water booster sets feature stainless steel multistage pumps mounted on a powder coated steel base plate.

The Velocity sets are controlled by our advanced variable speed control panel and different configurations are available offering maximum flow rates ranging from 4.4m3/h (75l/min) – 29m3/h (480l/min) per pump and maximum head pressures ranging from 1.0 – 16 bar.

!" August 2021

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