When did you last top up your chemical inhibitor levels?

One of the most important (and most overlooked) parts of your central heating system is the levels of chemical inhibitor that's inside it. If you have no idea what chemical inhibitor is then you definitely need to read on. This article will show you how you can potentially avoid a central heating system breakdown and how to keep the costs down on your heating bills, all by protecting your system with chemical inhibitor.

Why does your central heating need protecting?

Your central heating system is made up of several important components, such as:
  • Boiler
  • Pump
  • Radiators
  • Pipes
One of the main things that these components have in common is that they contain parts made of metal. Another commonality is they all have large amounts of water passing through them.

A chemical reaction

When water comes into constant contact with metal, over time a chemical reaction takes place that can cause the metal to corrode. In terms of your central heating system, this corrosion takes place internally and, if left untreated, can be catastrophic for the smooth running of your system.

Radiator sludge

The corrosion that can occur in your heating system will eventually lead to rusting. In turn this will cause tiny flakes of metal to fall into the water and get washed around your pipework. Usually these flakes of metal will come to rest in the bottom of a radiator, causing a large build up of horrible brown sludge at the bottom. The rusted metal can also block up your pipework, narrowing the about of space that the water has to flow through. A good analogy is the furring up of your arteries, causing your heart to work harder in order to pump blood around your body.

Heating system breakdown

When the sludge settles in radiators or in your pipes, your radiators will not be getting as hot as they should. A typical symptom is when your radiator feels cold at the bottom and hot at the top. Because your rooms are not getting as hot as you need, this will often cause you to turn the thermostat up higher, consequently using more energy. This will inevitably lead to higher bills. Additionally, because the radiators and pipes have become blocked with sludge, it means that your pump and boiler are put under extra strain in order to keep the water flowing around the system. If left untreated, the life of your pump and boiler will be severely shortened and invariably leads to an expensive heating system breakdown, usually at the coldest time of the year when you most need it. You may also find that because it's the coldest time of the year, it's very difficult to get a plumber to come round quickly as they are busy dealing with similar emergencies.

Top up your chemical inhibitor

The description above is a worst case scenario and usually takes a few years to build up to such a critical problem. However, if the problem is not addressed, the worst case scenario will eventually occur. The reason chemical inhibitor is so important is because it seriously slows down the rate of corrosion that occurs between the water and metal within your heating system. To see the difference between the difference between water containing inhibitor and water without, see Jimmy the plumber's nail test below:
If you haven't had your chemical inhibitor levels topped up within the last year, or you've never even thought about chemical inhibitor before, then it's time you addressed the issue.

Annual maintenance

We recommend that you have your boiler serviced by a professional Gas Safe registered plumber every 12 months, much like you would get a car MOT'd. Part of this maintenance process will be topping up the chemical inhibitor and it could save you hundreds of pounds over the long term. Your heating bills will be lower and your boiler is far less likely to breakdown as the inhibitor will assist with keeping your system running smoothly and efficiently.

Do it yourself

Though we recommend that you employ the services of a professional plumber for performing the annual maintenance on your heating system, there is no reason why you can't do the fairly easy task of topping up your inhibitor levels yourself. Below are the three main methods of adding inhibitor to your system, depending on the type of central heating system that you have. While adding inhibitor is one of the easier heating maintenance tasks, if you are not comfortable with carrying out plumbing jobs yourself or if you are unsure about anything, we recommend you leave it to a professional!

How to add inhibitor via a heated towel rail


How to add inhibitor via a loft tank rail


How to add inhibitor to a pressurised heating system



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23 October 2018