Think of a campfire covered with damp leaves. It burns sluggishly, and it’s orange, smoky and cool. Now think of a bright flame, roaring with a brilliant blue colour – much hotter and with very little smoke. Think of an unserviced boiler, and it’s like the campfire – even though you haven’t covered it in damp leaves.
A gas boiler operates at best efficiency when all its component parts are correctly balanced and functioning properly. So, when it works perfectly, the right ratio of fuel to air mixes with the burner. This produces plenty of oxygen for perfect combustion: a clean, blue flame that reaches as close to the theoretical maximum temperature as possible (and so transfers the majority of the energy into the central heating water).
In an ideal scenario, using modern, “condensing” boilers, the hottest part of the heat left in the exhaust gases then has a chance to exchange further heat in the secondary heat exchanger before being exhausted out of the flue. For Boiler Servicing Cheltenham, visit //www.blu-fish.co.uk/gas-heating-services-cheltenham/boiler-servicing-cheltenham
When things go wrong in a well-used gas boiler, neglect can knock out the balance in two ways.
First, dirt gets inside: dust and debris find their way into the system, along with corrosion products deposited onto the important parts of the boiler – the burner and especially the primary heat exchanger. This blocks efficient heat transfer from the combustion gas to the water going to our radiators and hot water. The thin metal surfaces that make up the heat exchanger have been carefully engineered to create a very large surface area for an optimum energy transfer. As soon as soot or scale builds up, the result is like wrapping a blanket around this bit of kit. And as the temperature drops, that extra, wasted energy disappears up the flue – but you’re still paying for it. You want to avoid a blanket effect in your boiler: it stops expensive gas energy from warming your home.
Second, through wear, dirt, or corrosion, the finely tuned air-to-gas ratio is no longer correct. Now combustion is incomplete. The telltale is a lazy, yellow flame instead of a nice, bright blue. This lazy flame is also responsible for carbon monoxide and soot – two products we really don’t want, because they mean you’re burning full of potential energy which hasn’t quite become enough controlled heat. Think of a candle about to die. Not all of the wax is completely vaporised and burned. Some bits of the wax turn directly into carbon soot or escape as unburned paraffin fumes. If the heat’s escaping as unburned particles instead of usable heat, you’re losing energy – just as you do with a poor candle flame. If you have a poor boiler flame, the effect is wasted energy.
