Power Flushing

Power Flushing in General

It is recommended by the heating industry that heating systems should be flushed on average every ten years and less depending on the water quality in your area. New systems should be pre-flushed during the commissioning stage to remove installation debris, swarf, manufacturing lubricants, and varnishes, etc.

People only turn to Power Flushing when the heating system is totally underperforming, and radiators have developed cold spots or are only partially heating. Power flushing is very often the “Last Chance Saloon” for heating systems before a re-pipe.

Or if a new boiler is being installed on an old system. In some cases, boilers are installed on old systems that themselves need to be replaced.

The Company cannot be held or will accept any responsibility whatsoever for any underlying issues, defects, or faults on old systems that may be high lighted by Flushing

Power Flushing causes leaks?

Power flushing is conducted at higher pressures than your heating system normally runs at. However, it is a lower pressure than the maximum pressure your system should be able to take. Your boiler pressure relief valve opens at 3.0 bar and flushing machines generally generate between 1.5 & 2.0 Bar – well below the 3.0 bar the pressure relief valve is calibrated. So your system should be able to take this pressure, if it can’t then your system is a problem waiting to happen and the sludge could be what is holding it together. It is not uncommon for valve seals to leak after power flushing as the sludge is what’s forming the seal and if left undetected can cause major damage where the surface dame may look minimal.


First Signs

Underperforming Radiators are the first signs of sludge problem and if ignored can result in expensive repairs or total boiler failure in the worst case a full new system needing to be installed.

A well performing radiator and a poorly performing radiator

Badly Sludged Systems

When Sludge is not removed from the system pipework, it is like cholesterol building up in our arteries and veins, it can form solid hard lumps that will catastrophically block pipes, valves, etc as they move around the system. If these lumps cannot be removed by flushing then the system may need to be re-piped.


Installing a New Boiler

It is important that a system is cleaned when a new boiler is being installed on your old system. If you have a heart transplant and you do not deal with cholesterol then your new heart will fail, the same can be said for your boiler as it is the heart of your heating system.

A clean heat exchanger and a blocked heat exchanger

Do I need a machine?

Is power flushing the same as connecting a hosepipe from the mains?

The Plumber said: connect a hosepipe to a drain-off point and let the mains water run through until it is clean. (Draining the system down will also clean, all the sludge out)!

This does not work as water will always go the easiest way and this method does come close to the modern techniques and the use of power flush machines, chemicals, and or magnets. It also only follows and cleans one path (least line of resistance), not nearly the entire system – at very best it’s 20% effective also -simply Introducing a cleaning agent and not removing it, will only lighten the sludge and cause even more damage to the system if not correctly remove and neutralised. These agents should only be used by a qualified and competent person following the manufacturer’s instructions. 

Magnetic Filter Flushing

A power flush machine circulates a large volume in excess of 100L\pm (Litres per minute) of water under pressure 1.5 -2.0Bar (depending on machine), around your system. An Average Domestic Heating Circulation Pump will create about 0.5 – 0.7 bar and might manage 15L\pm, magnetic filters rely on the system pumps to move the sludge and or rust and they are not effective when it comes to moving heavy deposits through the Filters. They are very effective when used in conjunction with Power Flush Machines and can conserve a lot of water that would be wasted with just a power flusher alone. Also if it’s a very old an fragile system and minimum force is preferred.


Power Flushing

Power flushing utilises high flow rates, under high pressure. These high flow rates move the sludge-like a fast-moving river moves silt,  it can be filtered out and the additional pressure help to push the heavier sludge.

Does power flushing remove all the sludge from a system?

Power flushing removes a large percentage of sludge and or rust – but not all of it. It is not possible to remove all the sludge from a system especially older systems and it will not remove hard or large solid blockages or lumps.

There is a Part/Component Broken Will Power flushing will fix it

If a part is broken and the system or boiler is not working due to the presence of sludge and the damaged component, cleaning the central heating will NOT fix that part. Even though the sludge may have caused it to fail and will probably break or damage the expensive new part – if the sludge being the likely cause is not removed by power flushing.

Power flushing did not work and did not remove all the sludge

Power flushing has limits and on really badly and heavily sludged systems it may not work. It will not unblock clogged systems either.

The systems most susceptible to sludge are: Open vented systems, G.B Systems, Microbore systems, and systems that have more than one type of pipe used were add-ons and repairs have occurred. And in the worst-case being systems with a hodgepodge of G.B, Non-Barrier P.E, Copper and Stainless Steel together in a system.

For example, if you have G.B  (Gunbarrel) and copper in your system then your system needs to be protected with corrosion inhibitors and earth bonding (your system regardless should have earth Bonding)

If an older non-barrier P.E (pex) pipe has been used this causes re-oxygenation of the water in the system and the system literally eats itself.

Any of these, generally need to be POWDER FLUSHED for better results which standard power flushing chemicals have very little effect on. Be aware that Power Flushing can result in total failure of some of the pipework, it is the last resort to re-piping, and re-piping should only be undertaken as a last resort. Be aware that the system is at end of service life and this is purely a “Stop Gap”.

Central heating sludge nuggets/flakes

Sludge flaking is caused when the sludge in the system has hardened into flakes or nuggets of various sizes and or the steel of the radiators, expansion tanks (F&E tanks), or older type boilers with steel or Iron heat exchangers rust and flakes fall off. These flakes and nuggets are much larger and harder than normal sludge, which is more mud-like. Once these started forming in the system, it becomes very easy to cause major problems within the boiler, pump, pipework, and radiators. The is the main cause of catastrophic system failure resulting in a complete refit of heating systems.

DIY, I do not need a Plumber or Heating Engineer.

Plumbers and Heating Engineers understand how the systems and boilers function, they are trained and understand how water moves through your system.

For the lay person, it’s a huge risk, not only is it a waste of time, energy, and money, think of the possible damage you could cause not just to the system or boiler but to your home.

The single biggest problem with DIY Flushing of any sort is that you don’t have the training, knowledge, tools, and equipment to deal with the challenges – not to mention unforeseen issues that may arise during the process. A plumber’s favourite expression is; “We repair what you’ve fixed” and in many cases, it is 100% true.

My System has lime scale I Think I need a Power flush

There cannot be simply a build of limescale in your central heating system.

In simple terms, the sludge in your system is composed of a small amount of limescale, debris, and swarf with over 90% actual rust.  The composition values in percentages will vary from system to system and geographical areas and water sources will have differences in water hardness values, including dissolved and suspended minerals. Also, the installation and design quality of the system will have a huge effect on the amount of sludge in the system.

There can however if you have a combi-boiler there can be a build-up of limescale in your boilers hot water heat exchanger (plated or secondary heat exchanger) but again, this only applies to Combi Boilers and is only on the domestic water side and not the heating side, these heat exchangers are only found in combi-boilers and are not present in systems that use a hot water tank or cylinder. These Heat Exchangers can be cleaned using different methods or replaced if necessary. But Heating Sludge can and will cause total failure of these units too.

A central heating flush is to flush the boiler, pipes, and radiators only. Water from your central Heating system should never mix with the domestic water (Water from taps) Note Flushing through the boilers heat exchanger is not always recommended, refer to the boiler manufacturers Instruct Manual.

Power flushing can stop my system losing pressure (sealed & semi-sealed systems only)?

The leak needs to be fixed to stop the loss of pressure. If anything, a flush will make the pressure loss worse as it will remove the sludge that may be causing and then re-plugging the leak, ultimately the leak will become larger than the sludge can plug and the result is a major leak. The freshwater being introduced to repressurise the system is accelerate the corrosion and degradation in the system.

If you cannot find an actual leak you may have several micro leaks, a quality, manufacturer approved internal leak sealer may solve this issue, however, if it is a water-to-water leak that can occur on the hot water tanks/cylinder internal heating coil other action will need to be taken if this is the case.

It is important that the system is cleaned for an internal leak sealer to be effective, otherwise, the sealer will not work effectively. It will bond with the sludge and ultimately fail.