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Should I power flush my central heating

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  • 09-07-2021
Should I power flush my central heating

Many homeowners ask the question: should I power flush my central heating? We look at whether power flushing is a good idea and what happens during a power flush.

Is power flushing My Heating a good idea?

Power flushing is the simple process of pumping water through your central heating system at high speeds and with other cleaning chemicals. Powerflushing is a great way of increasing the efficiency and longevity of your central heating system and can help you pick up on certain risks throughout your system, such as scabs.

How Does Powerflushing Help?

Scabs are thin layers within your systems, usually comprising of rust or sludge rust and can easily become dislodged, allowing for leaks. 

Heavy hot water flow or sludge could cause these scabs to become dislodged.  Scabs are already a problem to begin with, and power flushing usually reveals scabs. If left unmanaged, scabs can easily wear away and cause leaks by themselves, generally costing more. 

It is always a good idea to have a gas safe registered engineer in the house when a scab becomes dislodged. Powerflushing doesn't cause scabs but can help prevent them by protecting your system and preventing future corrosion. 

Powerflushing is a great investment into your future as it can improve your boiler's health and help prevent costly breakdowns.  On average, it is cheaper to annually service your boiler than it is to pay for the breakdowns in an average boilers lifetime that can easily be prevented through power flushing. 

Being left without a boiler due to breakdowns can be hard, especially during the winter months when you need them the most and prices for repairs are higher and usually all booked up. 

Powerflushing not only ensures you won't be out of a boiler but allows you to choose when your annual service is scheduled. Having the luxury to choose when you want your appointment, especially during the summer months, means more scheduling options are available while also possibly being cheaper due to off-peak seasons.   

What happens during a power flush?

A power flush has three general stages and can include pumping around additional chemicals to break down sludge or other build-ups further and can take an average of several hours to a whole day to complete.

1.

Step One.

An engineer will spend upwards of around 90 minutes power flushing the whole system in both directions until they deem the system clean and unfiltered; troublesome sections will require extra attention and may need to be worked on specifically through this duration. 

2.

Step Two.

once step one has been efficiently completed, the engineer will now add in the chemicals while carefully checking the PH balance of your system or combi boiler to prevent acidic corrosion.

3.

Step Three.

An engineer will now add inhibitor fluid to the process to help prevent further or future corrosion and build-up.

Adding inhibitor fluid to the process is generally the most lengthy process, and itself can take up to a day to complete due to size, condition, etc.

When does my central heating system need a power flush?

Whether it's simply one or multiple issues, power flushing will be beneficial to your system. Some common telltale signs include:

 Cold or cold patches on your radiators

 Black or sludge within your heating system

 Less efficient or poor circulation  

 High amounts of iron, usually within the sludge

 Overflowing or incorrect speed, power or energy setting

Another situation could be when you don't have a fault, such as when you have a new boiler installed. While your boiler may be new, your radiators or central heating may be old or use an older style.

A new boiler can add high pressure to older or clogged pipes and is worth consulting an engineer. A gas safe registered engineer will determine how to go forward with your central heating system, check for PH levels and balance, iron, other issues or factors, risk, corrosion, etc. During this assessment, the engineer will determine your system's needs, whether a full power flush is necessary or a less intensive dynamic flush and can help get your central heating system back to normal. You are required to have your central heating system power flushed after having a new boiler installed.

If you are interested in power flushing, we at EPH Plumbing and Heating offer an affordable power flushing service and highly trained gas safe registered expert engineers fully qualified to perform this process on your system. 

Will A power flush will actually cause leaks in a heating system?

In short, no. Gas safe registered engineers will assess a central heating system before performing any kind of flush and advise on the corresponding flush necessary and make any preparations prior. Examples include clear flow pumps with the intention of apply low pressure (two bars).

Certain spots within your system or radiators might have what is known as a 'scab'. Scabs are thin layers within your systems, usually comprising of rust or sludge rust and can easily become dislodged, allowing for leaks. Heavy hot water flow or sludge could cause these scrabs to become dislodged.

Scabs are already a problem to begin with, and power flushing usually reveals scabs. If left unmanaged, scabs can easily wear away and cause leaks by themselves, generally costing more. It is always a good idea to have a gas safe registered engineer in the house when a scab becomes dislodged or while your central heating system is being power flushed. It is worth getting scabbed tubing/pipes replaced or having them undergo pipework to prevent further issues or additional jobs.  

Can I power flush microbore systems?

While you CAN flush most microbore systems, it isn't advised. Extra time should be allocated for power flushing to compensate for microbore systems, and an engineer will have to assess the condition of the whole central heating system, including each radiator.

Some radiators could need to be replaced or changed over to conventional radiator valves, especially in the case of twin entry valves. The power flush will become more effective, plus there are the added benefits of your radiators providing higher heat than normal and higher efficiency levels.

Other recommendations or precautions include treating the system with flushing chemicals to clear or loosen up sludge buildup or debris; sludge free or clean water is easier to work with. Due to the nature of microbore systems, dirty water and thick sludge tends to build within the tubing/pipes, especially on bends, making power flushing difficult.

While there are risks, ultimately, power flushing is superior, more cost-effective and will produce greater results than any other rivalling method such as a gravity clean. For any further or specific advice, our gas safe engineers and plumbers are happy to help.

Power flushing radiators in Southampton

Will pressure from a power flushing damage the boiler?

Simply put, no.When producing their boilers, all boiler manufacturers must test them to withstand pressures of up to 4.5 bars, whether that's a combi boiler or a system boiler. No type of flushing exceeds 2 bars of pressure, including power flushing, so you can rest assured that power flushing won't harm your boiler or cost you additional money.

Engineers will always assess and check your boilers and central heating systems and their condition before performing a power flush; some pipes/tubing may require pipework due to 'scabs'. Scabs can cause leaks and eventually corrode or become knocked loose by sludge, debris or water; it is more cost-effective to take care of them before power flushing and save you money on a future job.

Can I heat water during a power flush?  

Yes.You can still have hot water during a power flush; however, it will involve some technical DIY know-how and some possible roundabout methods. 

Boilers need a certain amount of pressure to fire; reversing the flow direction in some circumstances may be the answer during a clear flow pump. An average combi boiler needs an average of 0.5 bars before it will fire.

In the circumstance that your boiler won't fire because you have removed the system circulator, depending on the boiler, you can trick the boiler into continuing to fire still through adjusting the control panel or setup on the boiler. 

This is particularly great because you don't have to worry about overheating or hot water due to the pace at which the water is being pumped, which will take heat away from the heat exchanger; this is great as the temperature of the heat exchanger is important.

As a last resort DIY method, slightly closing the isolating valve on the returning orientation will instantaneously increase the pressure; monitor this while the water heats up. For any further or specific advice, our gas safe engineers and plumbers are happy to help.

Can power flushing remove all debris within my system?

Technically no, however most debris and sludge will be removed as water is pumped around during the process. 

Certain boilers such as gas combi boilers may require extra steps such as removing and separately flushing the hot water heat exchanger and then refitting said heat exchanger. 

If your system is particularly old, then it may be best to consult a registered gas safe engineer as well as enquire into other solutions and their prices.


Do you need a powerflush in the Southampton and Hampshire area? For more information or advice about power flushing, follow the link below.