FOCUS ON: PIPES, VALVES & FITTINGS
COVER STORY
Caleffi PRV Series 533.
CALEFFI’S PRESSURE- REDUCING VALVE RANGE OFFERS SOLUTIONS FROM DOMESTIC INSTALLATIONS THROUGH TO DEMANDING COMMERCIAL APPLICATIONS, OUTLINES ALTECNIC COUNTRY MANAGER ROI & NI CHRIS REILLY… Why pressure control matters Caleffi PRV Series 536.
Caleffi PRV Series 535.
Chris Reilly.
Maintaining stable water pressure is essential for the efficient operation and long-term protection of domestic and commercial water systems. Excessive or fluctuating pressure can increase water consumption, accelerate wear on system components, create noise within pipework and contribute to premature equipment failure. Pressure reducing valves (PRVs) address these challenges by reducing and stabilising incoming mains pressure to consistent downstream pressure. They operate by balancing the force of an adjustable spring against downstream water pressure acting on a regulating element, either a diaphragm or piston, depending on the valve design. The Caleffi PRV range comprises Series 533, 535 and 536, offering solutions from domestic installations through to demanding commercial applications. While all three stabilise downstream pressure, their differing operating mechanisms and features allow them to meet specific installation requirements. In this article, we explore the characteristics of each series and the applications they have been designed to serve.
pipework, appliances, cylinders, water heaters, taps and showers from unnecessary stress and wear. They can also help reduce water consumption, minimise pressure-related noise and improve overall system performance. All three ranges feature serviceable cartridge assemblies, allowing internal components to be inspected, cleaned or replaced without removing the valve body from the pipework. They are also WRAS approved for potable water applications and supported by a five-year warranty, providing confidence in their long-term performance and compliance with UK Water Supply Regulations. Series 533 & 535: Diaphragm- operated performance Both the Series 533 and Series 535 are available in standard and high- temperature variants, making them suitable for both cold and hot water systems. The high-temperature models are certified to EN 1567 and can operate with inlet temperatures up to 80°C. Both valves utilise diaphragm-operated mechanisms, where water pressure acting on the diaphragm is balanced against an adjustable spring to maintain a consistent outlet pressure. Their inclined body design also offers advantages over traditional straight- through valves. The angled flow path reduces turbulence and pressure-related
noise, supporting quieter operation and smoother pressure regulation during varying demand conditions. Series 533: A proven all-rounder Series 533 is one of Caleffi’s most widely used pressure-reducing valves, designed for domestic and light commercial applications where reliability and straightforward maintenance are key priorities. An integrated filter mesh helps protect internal components from debris entering the valve, while pressure gauge ports allow installers to monitor and verify system pressures during commissioning and servicing. The 533.H high-temperature version uses materials designed for elevated operating temperatures while maintaining long-term reliability. Internal moving components are manufactured from engineering plastics to help minimise scale deposits, while the diaphragm provides improved resistance to pressure fluctuations and ageing. Series 535: Faster commissioning through pre- adjustment While operating on the same principles as Series 533, Series 535 introduces a pre-adjustable design that enables the desired outlet pressure to be set before installation.
Shared features across the range
By controlling excessive mains pressure, all three ranges help protect downstream
56 | PLUMBING & HEATING MAGAZINE
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