Why does Limescale Build Up in your Central Heating System?

Nov 23, 2022 | General

Limescale – the silent assassin. Quietly, and usually out of sight, it collects in pipework and never stops accumulating.  The heating of water exacerbates its effects and if you live in a hard water area, with a requirement for heated water, you can expect your pipes to suffer from it.  

It’s also especially prevalent – and damaging – to your central heating system. Here’s what happens during the cycle of heating and cooling water in the system.  

Your hot water tank, which heats the hot water for your home, is not too dissimilar to the element in your kettle.  

In the tank, instead of an element, you have a pipe which flows to and from the boiler. The boiler heats the water and the heated water flows through the pipe into the hot water tank, where it is stored ready for use. 

If the water hasn’t been softened, i.e., you live in a hard water area and you don’t have a water softener, limescale will inevitably rear its ugly head.  Firstly, scale wraps itself around the outside of the pipe or coil that goes to and from the boiler. So, for the boiler to heat the water, it has to heat the pipe, to heat the scale, to heat the water!  The more scale you have on the pipe, the harder the boiler has to work to heat the water to heat the pipe, because the lumen of the pipe is reduced. 

But that’s not the only place that this nasty stuff accumulates. The pipework also heats the water that is stored inside the hot water tank. This encourages scale to also build-up at the base of the tank – increasingly so, as time goes on.   

So, what started out as a large, scale-free water tank, standing about five feet tall, within just three or four years, you’ll have a foot’s worth of limescale or chalk stacked up at the bottom of it. Every time the scale has to be heated before the water gets heated! 

Naturally, that’s going to cause a delay in the time it takes to properly heat the water. It could easily take a couple of hours longer than it should. Every week, month and year that passes, as more scale attaches itself to the stack, the boiler will have to work ever harder to ensure you receive the right amount of hot water. 

Not only does it take increasingly longer to heat the water, which is costing more and more in the way of gas and wear and tear, once the system’s done what it’s supposed to do, it’s at the mercy of the scale sucking up all that lovely warm water that’s just been prepared. It’s a vicious circle of nastiness. Little wonder, then, that so homeowners opt for a water softener, to prevent any of this nonsense from happening. 

If you are concerned about how much money you might be wasting on heating and hot water – and the longer-term damage limescale could be causing to your central heating system – now might be the time to start talking to us about installing a water softener.  

Speak to a friendly and knowledgeable member of the SJWS team today, by calling 01243 607494 or contact us by email: scott@sjbs.co.uk