HOT TOPICS
ALTECNIC COUNTRY MANAGER FOR ROI & NI CHRIS REILLY HIGHLIGHTS THE DIFFERENCES BETWEEN EACH TYPE OF EXPANSION VESSEL AND HOW THEY WORK ON THEIR SPECIFIC SYSTEM TYPE… Getting to know different vessel types
POTABLE VESSELS Potable vessels work using the same method. However, the water sits within a rubber bladder as the potable water (wholesome water) cannot sit against the metal due to it being oxygenated water. FLOW THROUGH VESSELS Flow through vessels are designed in a similar way to potable vessels. However, a special mushroom-shaped insert encourages flow through the vessel, preventing any stagnation. There are also flow through vessels with a top and bottom connection and the water flows directly through the vessel. SIZING YOUR EXPANSION VESSEL Correct sizing ensures your system can safely accommodate water volume changes when heated from 10°C to its maximum operational temperature (or higher under fault conditions).
An expansion vessel is a pressurised vessel that incorporates a bladder or diaphragm in its design and is installed in unvented heating, cooling, potable water and solar heating systems. These are also referred to by some manufacturers as expansion tanks or pressure vessels. A standard expansion vessel consists of a pressure vessel, water system connection, air valve and a membrane (diaphragm) or bladder. The membrane or bladder separates the pre-charged air or nitrogen from the system water. However, different expansion vessels are designed for the different types of systems that they are installed into. It is important to know the differences between each type of expansion vessel and how they work on their specific system type.
vessels are designed to be installed vertically, but always follow manufacturer guidance. • Fit isolation valves: to allow servicing or replacement without draining the entire system. • Minimise pipe runs: between the vessel and the system connection to reduce pressure loss. • Check pre-charge before commissioning: to ensure optimal performance from day one. Correct installation reduces wear, ensures accurate pressure management and prolongs vessel lifespan. CONCLUSION Understanding the different types of expansion vessels is essential for ensuring safe, efficient and long-lasting system performance. While heating vessels, potable vessels and flow- through vessels all serve the same fundamental purpose of managing pressure changes with each engineered to suit the specific requirements of its system. Correctly identifying and sizing the right vessel not only protects the system from pressure-related issues but also ensures compliance with regulations and prolongs equipment lifespan.
There are three main types of expansion vessels:
BEST PRACTICE FOR INSTALLATION
• Heating • Potable • Flow through
• Position close to the pump inlet: to maintain positive pressure throughout the system. • Install in a dry, accessible location: for easy inspection, maintenance and pre-charge testing. • Ensure correct orientation: most
HEATING VESSELS Heating vessels are designed to allow the water to sit within the metallic body with a diaphragm which holds the pre- charge.
For more information, contact Chris Reilly, Country Manager for Ireland, on +353 (0)85 215 2288 or e-mail chris.reilly@altecnic.co.uk or visit the website at www.altecnic.co.uk
PLUMBING & HEATING MAGAZINE | 75
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