HEATING SYSTEMS
MARK MOGEY, HEAD OF OEM SALES AT ALTECNIC, EXPLAINS EVERYTHING THAT YOU NEED TO KNOW ABOUT SEALED SYSTEMS AND THEIR COMPONENTS…
All You Need to Know About Sealed Systems
S ealed systems are now seen as the “norm” for domestic heating systems, with older systems usually having an open vented boiler with a feed and expansion vessel. Sealed systems do offer better running costs, ease in installation, and long-term savings compared to an open one. As a result, it is highly likely that most systems will be converted to a sealed system style. SEALED SYSTEM COMPONENTS A sealed system is closed to the atmosphere and eliminates the feed and expansion tank as well as associated pipework, thus reducing the risk of contamination, corrosion, and noise. For a sealed system to operate, it must include an expansion vessel, a safety relief valve (or pressure relief valve), a pressure gauge, and a filing loop.
vented to a sealed system of any size easy by packaging all the key components into a handy Robokit Extra®, available from 8 to 80 litres capacity. These include a nitrogen-filled reflex expansion vessel with a five-year warranty, a WRAS- approved ALT-ST0035 filling loop with gauge, a WRAS-approved safety relief valve, a mounting bracket, and a Quattro four-way manifold fitting. Each component has a significant role in ensuring that the sealed heating system runs efficiently. But how does each component work? EXPANSION IN THE SYSTEM Lack of expansion leads to unnecessary wear on the pump and other components. Systems may reach critical pressures (usually 3-bar) and discharge via the safety valve, not only wasting water but also forcing homeowners to call out engineers or even top up the system themselves. The constant introduction of
fresh water also adds air to the circuit and, consequently, corrosion. Expansion vessels allow for a higher volume of water to be stored. When the water is cold, the pre-charge pressure forces the diaphragm against the tank towards the inlet. As the temperature increases, the expanded water volume pushes against the diaphragm, creating additional volume for the water to enter. When the temperature decreases, the pre-charge pressure forces the water from the tank and back into the main heating system. This maintains a constant pressure that helps reduce energy consumption. Expansion vessels must be properly sized to operate correctly and avoid damage. More information on expansion vessel sizing can be found in the CIBSE Domestic Heating Guide. THE IMPORTANCE OF A FILLING LOOP Although filling loops are a key element
FINDING A COMPLETE SOLUTION Altecnic make converting from an open
“The device should be well suited to the system to ensure the safety of the end user.”
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