Power flushing is a technique used to clear out sludge from central heating system pipes, radiators, coils and heat exchangers.

Are you finding that most of your radiators remain cold (or lukewarm at best), despite continually turning up the thermostat? Or are they taking too long to heat up to maximum capacity? Or do some only heat up in some places, and not others? If any of these are the case then you might find that you have a clogged up central heating system.

This occurs over a long period of time, as sludge and sediment gradually starts to accumulate in both the pipes and radiators, until the blockage prevents your heating panels from warming up properly; the boiler lacks the power to pump the heat through the level of waste and scale that’s gathered together, and as a result the poor circulation of your heating system leaves you and your family craving the warmth that, although it isn’t there, you’re ultimately still paying for.

So what’s the best solution? Well, the best thing to do is call in a professional heating surveyor or gas inspector to first of all assess the damage and locate the major sources of the problem. If it is simply a case of a blocked heating system, then they will most likely recommend that you power flush your central heating system.

This involves hiring a professional, fully qualified engineer to clean the system by essentially ‘flushing’ out all of the built-up dirt and sludge from each outlet and/or clogged pipe, using the most effective tools and fast-working chemical solutions. But how much does flushing a central heating system cost?

Sings That The Central Heating System Needs Flushing

Areas in the system where there is accumulation of corrosion and sludge often require power flushing. Power flushing refers to the method used to remove sludge from central heating system pipes, heat exchangers, coils and radiators. The signs to look for are:

  • Boiler becoming noisy.
  • Boiler constantly breaking down.
  • Bleeding a radiator and still finding cold areas in it.
  • Radiators requiring a lot of time to warm up.
  • Central heating system losing its efficiency.
  • Central heating radiators taking a long time to heat up.
  • Radiators requiring frequent bleeding.
  • House does not feel warm even when the heating is on.

Why Power Flush Your Central Heating System?

Unlike draining your central heating system, which simply involves temporarily emptying the water supply, power-flushing involves connecting external equipment to your heating system, and then flushing out all the sludge and dirt using special chemical agents and high-speed water jets (or equivalent tools that achieve a similar result). There are several advantages of power-flushing your central heating, including the following:

  • Improved hot water flow
  • Rapid boiler response rate
  • Less noisy, more effective radiators
  • A more energy efficient property
  • A warmer home
  • Reduced heating bills

Checklist for Power Flushing Radiators/Central Heating System

  • Isolate boiler
  • Take note of the temperature of the radiators (to figure out the heavily clogged ones)
  • Take water sample
  • Connect any equipment or valves that may hinder reverse flow, i.e.,pump
  • Record each radiator’s TRV settings
  • Open all valves and take out the TRVs
  • Link power flushing unit
  • Take necessary steps to protect carpets etc
  • Carry out primary and secondary flushes. Force out stubborn sludge with vibrating tool of rubber mallet
  • Take out stubborn radiators and clean them manually with a hose. Refit the radiators afterwards .
  • Record temperature of each radiator and compare it to original radiators.
  • Test water
  • Add inhibitor (addition of neutralizer depends on the system) and test
  • Refit TRVs and other valves and apply initial settings.

Central Heating Power Flush Cost

power-flush-central-heating-systemPower flush costs. The final cost of power flushing usually depends on the number of radiators in your home affected by the faulty system. The average cost to power flush radiators is £470 for a two-bed house.

  • £600 for up to 10 radiators (usually around a three-bedroom semi-detached property)
  • £700 between 11-15 radiators (in total)
  • An additional £25 per radiator after that (up to a maximum of 20 radiators/outlets).

You might think this sounds a little expensive for what is basically a ‘clean’ of your system, but power flushing central heating system costs can be ‘recouped’ in reduced energy bills, less wasted heat and the time and money you save on potential follow-up repairs that, when you leave a clogged system unattended, could escalate into a major system overhaul.

Therefore it is always advised that you pay the up-front power flush central heating cost by budgeting carefully and comparing a number of different quotes from several companies; some even offer a free follow-up check, so be mindful of looking out for deals that could save you even more cash! Either way, power-flushing your central heating system will certainly seem worth the worry when you can relax in the warm, cosy comfort of your own home again.


Is it necessary to remove radiators?
I have flushed my radiators several times but they keep getting blocked, what to do?
Will the installation of a permanent magnetic filter cancel out the need to flush the system?
How frequent should I power flush the system?
Are there some types of central heating system that cannot be flushed?
Are TRV (rad valves) an issue?

*Source: econenergy.com, homeenergyservices.co.uk

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