Boiler Kettling

Boiler Kettling: Boiler Making Noises & How To Fix It

Banging! Clanking! Popping! Do you hear horrible boiler noise like these? Well, the culprit is one: kettling.

As horrible as it sounds, what does boiler kettling mean? How can it start? What can be done for boiler repair and how? What happens if you don’t take care of kettling? You’ll need to find answers to these questions to keep your boiler in an ideal condition.

Here you’ll find all the information on what boiler kettling means and how you can keep it from happening once more.

Let’s have a look!

What is Boiler Kettling?

Boiler kettling is a horrible blend of clanking, popping, and foaming sounds that originate from your old boiler while it’s in working mode. It’s a disturbing sound for any property holder to hear, and can undoubtedly upset anybody trying to relax in their home.

The good news is that there are ways you can counter this irritating sound. But first, we must know the reasons for boiler kettling. As they say, for a solution, one must understand the reason.

What Causes Boiler Kettling?

There are a few reasons why a kettling sound is coming from your boiler. The two most common factors for boiler kettling are:

  • Chemical factors
  • Mechanical factors

Chemical Factors: How It Causes Kettling?
Your boiler shouldn’t generally be at the forefront of your thoughts a ton of the time. The two most basic chemical factors for boiler kettling are:

  • Foaming
  • Deposition

Mechanical Factors: How It Causes Kettling?
It needs to work to ensure your house is equipped with high temp water when you need it. The two most basic mechanical factors for boiler kettling are:

  • Thermostat
  • Casting Faults
  • System Design
  • Flow Rate Settings
  • Gas boiler pressure

These factors affect your boiler’s working capacity and result in cold water and steam issues by shutting down the boiler. Which carries us to the following questions:

Can Limescale Cause Boiler Kettling?

Composition of Limescale: It is composed of calcium carbonate that is amassed with time; it regularly damages heating devices.

Have you ever looked inside an old boiler? In case yes, then you must’ve seen the robust, caramel store covering the base. This white stuff is limescale. It is one of the significant reasons for boiler kettling.

Can Overheating Cause Boiler Kettling?

A broken indoor regulator causes overheating. This happens in boilers that are at the end of their life expectancy with pots and bolts out.
Improper alignment of your heater can give wrong temperature readings as well.

Can Holes or Leakage Cause Boiler Kettling?

If you begin to hear whistling or spluttering sounds, the principal thing you need to do is check for leaks. A hole in your system can be a reason behind your boiler kettling. You may need to look very hard as they can be in the problematic to-spot parts near your boiler. It could be a direct result of a low-quality installation you’ve had previously.

Can Magnetite Cause Boiler Kettling?

Magnetite is also known as ooze, which collects inside boiler lines. This dark, gooey substance includes rust and metal pieces that have broken up or eroded from within the water pipes.

In situations where both limescale and magnetite ooze are present, pipe blockage may get extreme, causing kettling and overheating.

How to Detect Boiler Kettling?

Other than the popping and clunking sounds, here are some more signs that may help you with detecting boiler kettling:

  • Siphon breakdown
  • Radiators are cold at the base
  • Draining radiators contain dirty water
  • Noticeable slime in replaced boiler parts
  • Breaks and holes in the heating exchanger

Kettling detected. Let’s fix it!

Boiler Making Noises & How to Fix it?

With the mandatory introduction off the beaten path, we should discuss some potential fixes for your loud and flawed heater.

Fixing Ketting Cause: Overheating
For handling the issue of overheating, check through the manual for the boiler and indoor regulator. If it’s ancient, start looking at costs or get an affordable range of new boilers for your home.

Fixing Ketting Cause: Limescale
Limescale develops normally due to the mineral substance of the water. This generally relies upon where your home is located, with changing degrees of calcium and different minerals. If you are a homeowner and tired of boiler breakdowns, a one-time solution is landlord boiler care.

As you can see, the cause for kettling will decide the necessary fixes. Thus, task one is to hire a Gas Safe enlisted engineer to come and look at your boiler. Throughout their examination, the specialist will presumably highlight one of the causes we’ve mentioned above and suggest a path forward.

Is Boiler Kettling Risky?

“Cure sometimes, treat often, comfort always.” This Hippocrates approach applies to evaporator kettling as well: basically, kettling isn’t dangerous as long as the heater’s safety parts are in good working order. Take all the safety precautions as given in the manual or by the installer. However, don’t hold the issue either – the limescale and slop that cause kettling may also hinder the heater’s safety valves. It is always a good idea to take professional help before it becomes a risk.

The Cost of Fixing Boiler Kettling

Kettling boiler fix is dependent upon two factors, and so do its cost:

  • Cleaning boiler parts
  • Replacing boiler parts

Fixing Cost: Cleaning Boiler Parts

Force flush and clean the whole system. If slime or limescale develops in your radiators, you’ll see them growing—making clamours of their own.

Since you’re getting the exchanger cleaned along these lines, it might be ideal to do a forced flush or potentially synthetic clean of the whole section of pipes and radiators.

After the forced flush, the boiler needs to be flushed with plain water. At that point, it will be treated with an inhibitor to avert future rusting and limescale growth.

A thorough cleanup of limescale buildup may cost you between £200-300, depending upon how damaged the system is, and which synthetic materials are used in the cleaning process.

Fixing Cost: Replacing Boiler Parts

When we talk about replacement, fixing cost varies depending upon which part of the boiler needs replacement. For your ease, common kettling boiler replacement parts are given:

Replace the boiler
If your boiler is 20 years or more old, and it just starts kettling great, praise to the boiler! In any case, you can anticipate that this scene could be the first sign of other damage. In this case, your most ideal option is to trade the boiler for another one. The boiler cost calculator will give you an average estimate of the expense. For instance, a new combi or system boiler will cost between £600 – £850 for a model depending on the boiler size.

Replace the circulator siphon
As we’ve referenced before, your boiler might be kettling because of a circulator siphon. Regardless of whether it needs fixes or replacement, your insurance must cover it. If you’re not covered by insurance, at that point, hope to dish out around £250-350 for a replacement.

Replace the heat exchanger
While limescale and magnetite set up a camp in the pipework, their accumulation in the heat exchanger can be a primary reason for kettling. A Gas Safe specialist can scour the exchanger or clean it with a descaling process. It will eliminate both limescale and magnetite.

If your boiler is as old as the house, you’re living, and the odds are that a cleanup may not be sufficient. Because of the use, the part might be broken. If this is the situation, you will require a heat exchanger for your kettle; depending upon the make and model, these parts can slow you down in the scope of £350-600 – and fixes may not be a lot less expensive.

How to Save Boiler Repair Cost?

DIY boiler repairs are not illegal (technically) if you know why the breaks are there. For that, you’ll have to be a certified engineer to locate where the holes are and to sift through them. If you try to fix the heating system yourself, there is a high possibility that you’re penetrating the details of your guarantee. We encourage you to continue cautiously and draw in with 247 Home Rescue professional engineers to guarantee the safety and a productive solution for your concern. With that, you can also save £180 annually with their cover plans and have your boiler, appliances, and home covered as fast as now.

Will Kettling Cause Boiler Explosion?

A boiler “explosion” is somewhat startling; however, to prevent any damage after hearing kettling sounds, you should address the issue straight away.

How to Prevent Boiler Kettling in the Future?

Kettling can easily be fixed and prevented from reoccurring. Ways you can fix and avoid kettling:

  • Fit a Magnabooster
  • Powerflush the system
  • Replace the heat exchanger
  • All liquid inhibitor to the system


If you’ve tried all the solutions discussed above or you’re looking for an annual boiler cover plan, at that point, you need not go any farther than 247 Home Rescue. Depending on the kettling cause, they can replace faulty boiler parts, add preventative components, or flush and clean your system. Their friendly, certified professionals have been providing help for years now.

About Mat

A complete novice trying to navigate in the world of DIY. I bought my first home about 2 years ago & ever since I've been trying to research & learn how best to tackle common household problems.

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