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What is Power Flushing?

Our heating systems are vital for keeping us warm and safe all year round. And to do this effectively, they need to be clean. Over time, a muddy substance, known as ‘sludge’ can build up in your pipes and radiators. Left untreated, this plays havoc with the efficiency of your heating system, causing corrosion and blockages. In this blog we’ll explain what a power flush is, and how it can improve the efficiency of your heating system. So, if you’ve been having problems with cold radiators lately, read on!

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Before and after a power flush.What is power flushing?

Our heating systems are vital for keeping us warm and safe all year round. And to do this effectively, they need to be clean.

Over time, the water in your pipes, boiler and radiators deposits unwanted by-products like rust.

This rust (plus other dirt and debris) becomes an unpleasant, muddy substance, known as ‘sludge’.

This sludge plays havoc with the efficiency of your heating system, causing corrosion and blockages.

A report by the Department for Business, Energy and Industrial Strategy (BEIS) in February 2021 found that the build-up of sludge can reduce the efficiency of central heating systems by by 15%.

This means that your heating system can’t perform like it used to, and you might start to notice your radiators getting colder.

It can also damage individual parts of your heating system, leading to breakdowns, and can eventually lead to the need for a full boiler replacement in the most severe cases.

Fortunately, there’s a simple way to avert all these sludge-induced problems – a power flush.

A power flush is a cleansing process which cleans your entire central heating system, removing the sludge, which would otherwise cause damage and reduce efficiency. 

So if you’ve been having problems with cold radiators lately, read on!

Do I need a power flush?

Since a power flush deals with problems that you can’t even see, you might be wondering how you know if you need one.

Here are a few tell-tale signs to look out for:

Sign you need a power flush: Unexplained increases in your energy bills

A man emptying a piggy bank.If you’ve noticed that your energy bills are creeping up, this could signal that your heating system is not working as efficiently as it used to.

A possible cause of this, is that over time, sludge, rust and limescale has built up in your heating system.

Your boiler then must work harder, and burn more energy, to try and get hot water through blocked pipes, and past leaks.

Unfortunately, you might be noticing this reduction in efficiency in your wallet. But a power flush might be a simple fix for this.

Sign you need a power flush: Cold spots on your radiators

Are your radiators taking forever to warm up? Or have you noticed cold spots on them?

If the pipes are hot but your radiator’s cold, this could indicate a blockage.

In this state the heating system burns a lot more fuel as it struggles to heat the home.

If your radiators are stone cold all over (not just in spots) then corrosion debris may be blocking radiator pipes and the sooner the system is power flushed the better before blockages become permanent and need to be cut out.

Sign you need a power flush: issues when you bleed your radiators

If when you bleed your radiators, the water is discoloured, or no water escapes at all, this may also signal the need for a power flush.

Sign you need a power flush: Your hot water is unreliable

A sad woman with a towel on her head.If you’re finding that your hot water is fluctuating between hot and cold, or the water flow is reduced to a trickle, this could indicate problems such as corrosion in the heat exchanger, and limescale in the pipes.

Sign you need a power flush: Excessive noise

All heating systems will make some noise. But if you notice a new or unusual sound, such as a banging or knocking sound, this could be a sign that a power flush is needed.

Boilers make loud banging noises called “kettling” because corrosion debris blocks and damages the heat exchanger. Blockages reduce circulation causing boilers to overheat and cut out.

Boilers can also make a whistling noise as parts of it overheat or cycle on and off as the overheat stat continually cuts in.

A cold couple sitting by a radiator.

Sign you need a power flush: Boiler breakdowns

A mucky boiler and pump causes breakdowns. Evidence suggests that as many as 87% of boiler breakdowns are due to dirty water in your heating system, and this can be avoided by keeping your system clean.

What happens during a power flush?

If you think you might need a power flush, you might be wondering what’s involved.

During a power flush your engineer will connect a pump to your central heating system.

This pump will push chemicals and a descaler through the pipes, boiler and radiators at a high pressure. These chemicals remove sludge, rust, and limescale.

They will also use a corrosion inhibitor to help prevent future rust from forming. The engineer will collect and dispose of any contaminated water, debris or particles that they remove from the system.

Depending on the condition of the system, your Gas Safe engineer may also use special tools on the exterior of the radiator to dislodge stubborn blockages.

They should be able to measure the temperature of your radiators before they have started work and then show you the improvement after the power flush.

How long does a Power Flush take?

The length of time needed for a Power flush typically depends on your system’s size and condition, but it usually takes about a day.

What are the benefits of a power flush?

Here is what you stand to gain from having a power flush:

  • More efficient, hotter radiators
  • Greater energy efficiency and lower energy bills
  • Reduction in noise caused by blockages
  • Boost your heating system’s lifespan
  • Prevent costly breakdowns
  • Improved system reliability
  • Maintain boiler warranty

How often will I need a Power flush?

If you’re installing a new boiler, it may be necessary to flush your system to ensure that your new boiler can heat your home effectively, and won’t be damaged by sludge that is already in your radiators and pipes.

After all, there’s not much point installing a new efficient boiler if you’re connecting it to an absolute mess of blocked and corroded pipes.

The Heating People will be able to advise you on this.

If your system is correctly maintained, then a power flush should only be necessary once every 5 years.

As part of your annual boiler service, The Heating People will perform a visual inspection of your central heating system. They’ll identify any problem areas where corrosion has occurred, and will tell you whether a Power flush is necessary to remove any blockages.

Is a power flush messy?

No, a Power flush isn’t messy because it’s confined to your current heating system. Your engineer will just need to connect their power flush machine to the heating system at a convenient point and they’ll use a suitable drain to dispose of the waste water.

I have an old heating system – can a power flush cause a leak?

No. Power Flushing machines are designed so that there is no increase in pressure in your system. It is a high flow rate that makes power flushing effective, not high pressure.

Occasionally, an old heating system may have radiators with holes that are just holding together with rust. The Power flush may dislodge the rust, leading to a leak from the radiator. But this leak would occur imminently even without a power flush.

If a problem is revealed by the flushing process, it is better that it occurs whilst a heating engineer is present to remedy the problem, preventing an emergency situation.

Can pressure from a power flushing pump damage the boiler or heating system?

No. A power flushing machine does not increase the pressure in the system; it works using high flow rates and therefore won’t over-pressurise and damage the internals of a boiler.

How much does a Power flush cost?

There are lots of factors that will affect the price of a power flush such as size and complexity of your heating system, and whether any other issues or faults come to light.

As a guide, a Power Flush with The Heating People will cost approximately £400.

Useful Links

BEIS report

BEIS energy efficiency statistics Feb 2021

Which? Reviews on reducing energy bills