DripFix - About Limescale

www.dripfix.co.uk

DISCLAIMER - IMPORTANT: PLEASE READ

This article is provided for information purposes only. You should only attempt any procedures explained here if you are competent to perform the task and have the appropriate tools and materials, including any relevant safety equipment.

Readers acting upon this article do so at their own risk and no responsibility is accepted by the author or publisher for any loss or damage incurred by following the article or failing to follow it.

If in doubt always consult a properly qualified tradesperson or other competent person.

WHAT IS LIMESCALE?

Limescale is the general name for a deposit on water pipes and fittings formed from naturally occuring calcium bicarbonate when water is heated.

HOW IS LIMESCALE FORMED?

Calcium bicarbonate is found naturally dissolved in water in certain regions.

Normally the calcium bicarbonate stays dissolved in the water, but it changes to calcium carbonate once water is heated to 70^oC.

Calcium carbonate tends to separate from water and it clings to nearby surfaces, causing the white scaley deposit seen inside kettles and known as 'Limescale'.

WHAT DOES LIMESCALE DO TO PIPES?

On central heating systems and in hot water tanks and pipes the calcium carbonate forms a lining which grows thicker over time.

This gradually makes the inside of hot water pipes and tanks narrower as the layer of calcium grows thicker. Eventually pipes become blocked completely.

WHAT DOES LIMESCALE DO TO IMMERSION HEATERS?

Around heating elements such as immersion heaters in hot water tanks, the limescale grows until it is too thick for the heat generated by the immersion heater element to be transferred into the surrounding water.

The trapped heat then builds up in the immersion heater rod causing the immersion heater rod to burn out and fail.

WHAT DOES LIMESCALE DO TO BOILERS?

In central heating boilers the limescale builds up in the pipes running the heated water through the boiler, particularly in the area where gas energy is used to heat water (known as the 'heat exchanger'). The limescale build-up slows down the heating process and the flow of water, making the boiler less efficient and eventually causing boiler failure.

HOW CAN LIMESCALE BE PREVENTED?

In central heating systems limescale can be prevented by using a chemical descaler and protective additives in the water. These additives need to be changed every 12-24 months, depending on the amount of calcium in the local water supply.

Limescale can also be prevented by the use of chemical water softeners or electo-magnetic water conditioners, but a separate supply of untreated water for drinking must always be available in the property.