In combi boilers, water is heated directly from the mains supply, so the only time it’s exposed to the atmosphere is when it flows from the tap. During heating, the calcium bicarbonate naturally present in the water changes into calcium carbonate, producing carbon dioxide. This gas appears as millions of tiny bubbles, which can look like sediment but are completely harmless and purely cosmetic. If you fill a glass with hot water and let it cool, the bubbles will gradually disappear and the water will clear.
This effect is more noticeable in hard water areas and in boiler models with slower or lower flow rates.
Unlike an immersion heater, a combi boiler heats your water on demand, instead of storing it in a tank. A condensing boiler is any boiler that uses condensing technology to make better use of the heat they generate from burning fuels such as gas or oil-so a combi boiler can also be a condensing boiler.
As with all oil-fired appliances, Grant Condensing Combi Boilers require commissioning at the time of Installation. This simple process ensures that the boiler is working at peak efficiency which, in turn, will result in lower running costs and long-term reliability. Annual maintenance is also made easy by Grant’s cleverly designed front service access to both burner and all the internal serviceable parts. Installation must comply with the current Building Regulations.
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