When Does Central Heating Need Flushing?

The arrival of winter also comes with the need to take care of your central heating system. This ensures that it can operate at peak efficiency and not break down on you when you need it most.

One important thing that is often overlooked is whether or not your central heating system needs to be flushed out – this process helps remove any mineral deposits present in the pipes within your system.

This straightforward maintenance task should be performed before winter sets in fully. You only need to do it once every two to three years, unless you have gone a long time and the internal sludge build-up is significant.

The cold weather can exacerbate existing mineral build-up inside your central heating system, making it even more important that you flush your central heating system before winter.

How do you know if your central heating system needs a flush?

Flushing your central heating system is a process where water is passed through the pipes connecting your radiators at a high speed. This helps clean out any mineral deposits that may clog the water channels of your central heating system.

How do you know if your central heating system needs a flush?

The process can also help prevent more expensive damages to your central heating boiler or radiators by keeping them in tip-top condition for longer.

You can do this yourself or hire a professional to come out to your home.

If you have never flushed your heating system before or if it has been over three years since the last flushing, then there are some things to keep in mind when deciding whether or not to flush out your central heating system:

  • Does it run smoothly? 
  • Is the temperature consistent throughout every room?
  • Is it too hot or cold anywhere? 
  • Do any rooms feel humid?
  • Do any rooms smell bad when the heating is on?
  • Do you have noisy radiators and boiler?
  • Are there hot pipes but cold radiators in your house? 

Can you flush your own central heating system?

A lot of homeowners might wonder how often they should flush their heating system. There are a few factors that can influence this, such as the age and size of your home, the number of people in your household, and the type of heating system you have.

The best way to know if it’s the right time is by looking for signs that your system needs service. 

Some of these signs are:

  • increased frequency of hot water usage or decreased water temperature,
  • a magnet attaching to copper pipe-work (signs of iron sludge within)
  • slow recovery periods between showers (i.e., taking longer than expected for the hot water to come on), and
  • reduced efficiency in heating water.

If your system seems to have a lot of problems, then you should consider flushing it.

How do you know if your central heating system needs a flush?

Flushing the central heating system is also important because, over time, rust, sludge, sediment buildup, and other impurities can build up within the water exchanger or heat exchangers of your central heating system very quickly.

Power Flushing Your Central Heating System

There are 2 ways to flush a central heating system. Well 3 actually, but we’ll focus on the two options.

Which one you choose to do will depend on your level of competence with central heating systems.

Both methods will now be described below,

How to flush your heating system

The cheaper and easiest method to flush your own heating system is to pour a central heating cleaner in via an access point.

To do this, you’ll need the following (click each item to view) –

You will need to access a radiator valve, slowly pour in the solution using a dosing tool. Run the heating system for 6 – 12 hours.

The solution would work its way through your central heating system and dissolve sludges and deposits it finds along the way.

It would make your heating system more efficient but as the deposits will still be contained in your heating system, they might collect again somewhere else.

If you are unsure, then it might be worth contacting a heating professional for a consultation.

How to Powerflush a central heating system?

A power flush is an easy and cost-effective way to make sure your system runs as efficiently as possible. It is also ideal for anyone looking for a way to prolong the lifespan of their central heating system.

Power flushing your central heating system helps to remove all dirt particles from the entire system, preventing build-up which can cause problems in the future. Powerflushing removes these contaminants from the circulation pipes by using liquid detergents at high pressure (up to 12,000 psi).

The process can typically take up to around 8 hours to perform and only needs one person at home who can be present during the whole process.

A power flush involves circulating high volumes of (forced) water through a central heating system. This helps in cleaning out a central heating system.

After cleaning, a chemical treatment is added back into the pipes to remove debris and rust. It also helps prevent future contamination build-up.

To do a power flush of a heating system, you’ll often need the following (click each item to view) –

Once you have everything you need to flush your power system, you can proceed with the following steps.

Step 1

Check to make sure your heating system is off. Turn off your radiator valves and disconnect one. This would usually be a ground-level radiator in the front room of the hallway.

Step 2

Identify the location of your air bleed valve beside your radiator and leave it open. This will allow air to access your heating system, while water escapes from the disconnected valve.

Once all the water has drained from the system, you can disconnect the radiator and connect your power flushing machine to the return valves to access your central heating.

Note – For safety, you should make sure that the continuity of the earth bonding is continued before removing the radiator. 

There are also a few additional checks to do depending on whether you have an open vented heating system or a sealed system.

Step 3

Connect the plumb tub to the open valve pipe and extend the pipes outdoors – using your additional hoses – to an accessible drain. You should also lay cleaning sheets on the floor in the room you’re in.

Step 4

You should then cross-check that all your radiator valves are open. Then add the cleaning fluid solution to the power flushing machine.

Your machine should create a continuous loop through your heating system. So, switching on your power flusher should allow the water to begin circulating around the hating system.

Step 5

Switch on the boiler. This will allow the cleaning process to begin as the cleaning solution circulates through the system. As the process continues, you’ll begin to see the dirty water and sludgy build-up as it starts to flush out.

This needs to be done in both directions.

Depending on how dirty your central heating system is, you might need to repeat the process before you finally have clear water running through. 

Step 6

Radiators with heavy contamination will need to be worked on separately. In some instances, some further agitation is required to release sludge that is hard to shift.

Step 7

Once the central heating system is confirmed as clear, a neutralising solution is added to the system to further wash it through. This also helps to prevent a future build-up of sludge and debris.

Step 8

A corrosion inhibitor can then be added to the system. This is left to circulate while you disconnect the power flushing machine and release radiator valves.

Step 9

Turn on the water mains.

You should then leave the boiler on until all the air has escaped from the central heating system and you have an even flow of hot water in each radiator.

How often should you flush your heating system?

There are many benefits of flushing your heating system regularly during the winter months.

The most obvious benefit is preventing pipes from freezing and bursting in cold weather conditions. Preventing frozen pipes can save homeowners a lot of money on repairs by avoiding water damage and costly insurance deductibles.

Another important reason for flushing your heating system is to clear out the sediment buildup in your home’s piping. Doing this before it hardens into a thick sludge over time will keep your heating system working optimally.

How often should you flush your heating system?

It is worth noting however that as power flushing will move water around your central heating system at high speed, it tends to increase the pressure on any areas of weakness.

The last time I did a power flush, for instance, I had a radiator pipe leaking underneath the floorboards in my hallway.

If you have any rusting radiators, then they are also a risk.

If you have not done a flush of your heating system in a long time, then it may take more than one attempt at flushing for it to properly clean your central heating system.

This will prevent cold winter temperatures from freezing pipes and causing major damage.

Final Thoughts

It is important to note that if your system is very old or has heavy amounts of sludge, then a power flush will not remove all of it.

It will however remove a significant amount of it. 

A regular cleaning regime will go a long way in ensuring that any additional sludge is removed over time.

Knowing when your central heating needs a power flush can help you save money on repairs, better manage your energy usage, and increase the efficiency of your system.