How To Clean/Flush A Central Heating System

How do you keep your central heating water crystal clear and running at optimum efficiency? Here we explain exactly how to do it.

Your central heating system is your best friend, especially in the winter months.

During those cold days, you want your central heating system up and running so that you can stay warm. It also supplies you with warm water, which is essential for everyday comfort and convenience.

However, with time and use, like any other mechanical system, your central heating system will experience wear and tear and the heating water itself will become dirtier, leading to major drops in efficiency and increased risk of corrosion.

Yet, with proper maintenance and regular servicing, you can prolong the lifespan of your system, increase energy efficiency and significantly lower the possibility of a breakdown.

If you are looking for ways to maintain your CHS in top condition, regular cleaning is the best, simplest, and most efficient method.

Here we will explain exactly how to keep your system clean...

P.S Heatable includes a chemical flush and Adey magnetic filter with all new installs as standard, but you can upgrade to a ProFlush (magnacleanse) if you want an extra deep clean.

How To Clean A Central Heating System

Over time sludge and debris can build up and block the CHS, interfering with the system's functioning and causing it to work harder to accomplish the same results.

The increased pressure strains the system and can lead to damage and breakage.

Hence, it is crucial to get your system cleaned before a minor problem develops into a larger one.

Cleaning the CHS is not that difficult, and it can potentially be a DIY project.

However, we don't typically recommend that since it may invalidate your warranty and it can be a dirty job.

We shall now discuss the main method of central heating system cleaning, referred to as power flushing.

What is a Power Flush?

Power flushing is an easy and quick way to remove sludge and debris from the system.

In simple terms, it involves flooding the system with water at high pressure.

The high pressure dislodges sludge and debris, draining it out of the system.

Often, cleaning agents are also used along with high-pressure water.

The cocktail of chemicals used in these cleaning agents includes a descaler to help remove limescale, a corrosion inhibitor to help prevent the formation of rust and a specific chemical to help dislodge rust and remove sludge or crud.

When Should You Power Flush Your System?

If your boiler shows the following telltale sign, it's a sure sign that it needs a power flush:

There are cold spots on the radiator
The radiator is warm at the top and cold at the bottom
One of the radiators is not working
The heating system warms up very slowly
The thermostatic radiator valve is stuck in the off position

How To Power Flush Your CHS

In theory, you can carry out a power flush yourself as it's certainly not illegal, however, we wouldn't recommend it unless you are an experienced Gas Safe registered engineer.

Why not?

It may invalidate your boiler's warranty since many stipulate a power flush must be carried out by a registered Gas Safe Engineer
It's a dirty job involving dirty water
If it dislodges debris that exposes a leak you will need an engineer present to carry out the necessary repairs anyway

With that out of the way, let us continue...

Power flushing is done with the help of power flushers. They are readily available for hire in most tool hire shops.

Many flushing pumps even have an instantaneous flow reverser, which makes flushing a tad easier.

Power flushers come in different size ranges; a 25-litre tank is usually enough for residential CHSs.

If you are looking to clean a commercial boiler, a 200-litre tank will fulfil your requirement.

Step By Step Guide:

First things first: before you begin turn off your central heating system e.g. your boiler and allow it to cool before you begin the power flushing process.

When flushing your central heating system, follow the steps listed below:

Step 1:

First, lay a dust sheet or waste cloth to protect your floor and working area from water, dirt, and dust.

Flush and remove a radiator and insert the power flush nozzle.

If you have an open vented system, close off the feed and expansion pipes.

Step 2:

The power flush machine has multiple hoses. Select the appropriate one and connect its ends to the machine and the boiler.

Connect the inlet hose with the main water supply.

Connect the overflow hose and make sure it goes outside to the nearest drain.

The last valve that remains is for the dump hose. You will need to direct this towards the drainage, too.

Step 3:

When all the connections are in check, open all the radiator valves and switch on the power flush machine so water is circulating in your CHS.

Keep reversing the flow of water periodically using the lever on the machine.

Turn the dump lever upright and open the inlet valve after 10 to 15 minutes.

The dirty water will exit the boiler through the dump hose, and new water will circulate through the system.

Let the system run till you notice clean water coming from the dump hose.

Step 4:

Now close both the valves and set the machine to circulation mode.

There is a screw lid in front of the machine. Add your cleaning agent through this inlet.

Let the machine run for another 15 minutes, and do not forget to reverse the flow of water now and then.

Step 5:

After 15 minutes, flush each of the radiators individually. Turn off the valves of all the radiators except one.

Start power flushing and let the machine run for the next 5 minutes.

Step 6:

Now turn off the current one and repeat the same with the next radiator. Cover all the radiators this way.

Repeat the dumping procedure as before when you have flushed all the radiators. Open the dump and inlet valve.

Do not forget to open the valves of all the radiators as well!

Check for clean water exiting the dump hose. Once achieved, disconnect all the connections with the machine.

Now you have successfully power flushed your system and boilers, except the one you had taken out of the system to connect with the device.

Manually flush this radiator, and your system is thoroughly cleaned.

Related heating/energy guides:

Advantages Of Cleaning A CHS

A central heating system provides warmth and comfort to homeowners during those chilly months.

However, you need to take care of it so that it can perform optimally and efficiently without straining too much.

Many experts have long recommended cleaning the system; they emphasize proper maintenance and routine cleaning to enhance performance and lengthen the system's life span.

Here are some reasons why heating system experts are such strong advocates of regular cleaning:

Increased Comfort

The system takes longer to warm up because the debris in the system slows down the warming process, or completely blocks the flow of water in places.

This can lead to cold spots or radiators being completely cold or lukewarm.

Additionally, it hinders regular operation and prevents the system from reaching the desired temperature.

Increased Energy Efficiency

A system filled with unwanted substances is more under pressure. It has to work harder to achieve the same goal as a clean system.

Thus, it takes up more energy and drives up your heating bills.

Prolong the Life of Your Boiler

An unclean system is more likely to put a strain on your system, in particular your boiler.

Also, the probability of rust and other impurities corroding other parts of the system is very high. With regular cleaning, you take the load off the system.

Save on Expensive Repairs

It is always better to address minor repairs promptly than bear big ones.

Regular cleaning ensures you inspect and maintain the system, reducing the possibility of more extensive damage caused by rust and corrosion.

In fact, dirty central heating water is one of the leading causes of corrosion and rust developing on important and expensive boiler components, such as the heat exchanger.

How To Clean A Central Heating System Conclusion

A power flush is an effective way to give your central heating system a deep clean and maintain the quality of your heating water.

In turn, this prevents harmful debris and sludge from wreaking havoc in your system and causing damage to major components.

This simple, easy and quick procedure offers so many benefits that it is hard to ignore it.

You can do it yourself, but we would advise you to hire a professional to do it for you.

After cleaning, you will have a more efficient system that performs better and you can have the peace of mind that you have helped limit rust and corrosion as much as possible.