Get quotes to powerflush a central heating system

If you have noticed that your radiators take a long time to heat up, or are riddled with cold spots then it might be time for your central heating system to be powerflushed.

Common symptoms of needing a powerflush include;

  • Noisey banging boiler called “kettling”
  • Boiler cutting out due to slow circulation
  • Cold spots at the bottom of a radiator clogged up from sludge
  • Cold spots at the top of a radiator from air
  • Radiators very slow to heat or stone cold from blocked circulation
  • Hot water in taps from a combi boiler fluctuating from hot to cold

What is powerflushing?

Powerflushing is the use of chemicals and high flow rate to break down the build-up of rust debris, also known as black sludge, and penetrate through stubborn blockages in the central heating system. Powerflushing involves using a powerflush machine. This machine has a high flow rate and is able to reverse the flow of the system, to push the water in both directions to really force out stubborn debris. 

This vigorous flow coupled with the chemicals can remove the iron oxide sludge debris out of the pipework and radiators. The powerflush engineer will also create a back and forth motion of water with his machine to agitate the inside of the pipework to help loosen any build-up of sludge (they may also agitate the outside of the radiators depending on the fragility of the system). Where some people think that fitting a magnet filter near the boiler to catch debris is enough, this will only catch loose debris travelling around the system with the flow of water but will not remove any build-up of sludge trapped in radiators or pipework, only the power flush will do that.

Why do British Gas say I need a power flush?

If you have a homecare agreement with British Gas and they maintain your boiler, before British Gas replaces any parts on the central heating system, they want the new part being plumbed into a clean sludge-free system to avoid the new part being destroyed by debris. This is why British Gas usually insists on a powerflush before they replace parts. The good news is even when on a British Gas service contract, check with them but you are usually completely in your rights to shop around for the best quote and get the powerflush completed by someone else, as long as you have an invoice or some form of documentation to prove that you have paid for a powerflush on your central heating system.

System flush vs power flush vs chemical flush

Sometimes it can get tricky understanding what it is that your system requires to get it back to optimal working performance. Especially when tradespeople might use different jargon to advise on the same course of action. 

If a heating engineer has told you to get a system flush and you got a second opinion from another heating engineer mentioning a power flush… yes, they are both referring to the same chemical clean.

A power flush, also referred to as a system flush or a system power flush, just means cleaning out the entire central heating circuit with the use of the powerflush machine and chemicals. Do not bother with doing a partial flush, paying someone to come in and not flush out all of the radiators because once the circuit is back on in winter, the sludge debris that was sitting in a different part of pipework will just contaminate the cleaned out radiators.

When told you need a chemical flush, best to get clarity from the gas engineer, are they referring to a powerflush, or are they meaning using chemicals to dose the system, travel around by turning the heating on, and then draining down the system. This can work if the system is not badly blocked. If you are already paying out a lot of money, then best to just do a more intense version with better results and powerflush. There is no draining down for a powerflush, but rather keeping the system pressurised and pushing out the dirty water while constantly topping up with clean water, this way is to prevent any further blockages in elbows of pipework that draining down can cause.

How much will it cost to powerflush?

The total cost of the powerflush can be from a man-in-van offering to do it for just a few hours labour and the cost of hiring a powerflushing machine (from £300) to paying a specialised company, who own the equipment and more familiar with different scenarios they may come across on different heating systems (from £400). Most often, a powerflush is completed in a day. Smaller systems require just half of the day. Time taken to powerflush will depend on how often the engineer carries out a powerflush, as someone hiring the equipment and not too familiar or confident with its operating, may take longer than someone who does this daily.

Other factors affecting the cost are;

  • how many floors are involved in your property as some companies will charge per floor
  • how many radiators / towel rails / loops of underfloor heating are in the home
  • what size pump you might have (large homes might run on a commercial sized pump)
  • If the system requires a first visit of a pre-treatment of the cleaning chemicals before the day of power flushing

How much labour costs to power flush

Per

Average total labour cost

Powerflush 7 radiators

Per day

£400 

Powerflush 12 radiators

Per day

£560 

Pre-treat a blocked system and then powerflush 10 radiators

Per day

£620

Powerflush 12 radiators and change a circulatory pump

Per day

£660

Is my system too old to powerflush?

A big concern is whether a system is too old to handle a powerflush or if the powerflush will result in leaks, with high pressure bursting through old pipework. As long as your central heating system has water running through the boiler, and a circuit of pipework, it is suitable to be powerflushed.

Powerflush cleaner chemicals are mostly non-acidic therefore are safe and do not cause any damage to copper or plastic pipes (there is an acid option for a more vigorous clean and heating engineers will then neutralise the system with neutralising crystals afterwards but if your system is fragile they will not use this option).

A boiler, for safety reasons, is designed to handle water pressure of up to 4.5 bar. The maximum pressure of a power flushing pump will never exceed much more than 2 bar of pressure, therefore it is not putting the central heating system under any unnecessary stress. Worst case, is removing the sludge, the sludge might be eating its way through radiators and the debris acting as a cork, so once the debris has been removed, this may expose existing pin-holes in radiators. These would eventually become apparent, with or without a powerflush, as eventually the rust eating through would be too big a hole to ‘self-seal’.

How often should I get a powerflush?

It is suggested that a powerflush is carried out on a system every 5 - 6 years. This will prolong the life of the boiler. During this time span, it means that any build up of sludge that starts after an initial powerflush will be flushed out again to avoid solid blockages forming over the years. 

A powerflush is also needed when a new boiler is being installed. A new boiler’s components, like a heat exchanger, diverter valve, pump… will be protected by not having  sludge debris running through the boiler. If a brand new boiler is installed into a dirty system, within two years you might need to replace a burnt-out pump or damaged heat exchanger, ruined from sludge.

Systems that are prone to debris, perhaps badly plumbed in pipework that draws in air, microbore systems where the pipework is so thin that it only takes a tiny bit of debris to block the system or single pipe systems where there is no real control of where to send the chemical water during the powerflush but more on only where the system will allow the flow, these types of systems may need a powerflush more frequently than standard systems to maintain the boilers and keep heat reaching radiators. Microbore systems can be effectively powerflushed but might just need a bit more attention and time of the day from the heating engineer carrying out the flush. For best results with microbore, single pipe or badly blocked systems is to actually put the chemical cleaner in a few weeks before the intended powerflush to really give the chemicals a chance to circulate and start breaking down debris blockages.

However often your system is powerflushed, it is good practice to yearly top the system up with a corrosion inhibitor. This will not prevent corrosion but will slow down the pace of it re-building.


Estimates for common heating engineer jobs;

Job Estimate
Cost to replace a hot water immersion heater £275
Cost to fit underfloor heating £250
Cost to replace a vented hot water cylinder £330
Cost to replace a heating programmer £180
Cost to powerflush a central heating system £500 Visit
New combi or system boiler installation – like for like replacement £500
Cost to install a ground source heat pump £3750
Cost to fix a boiler fault error code £85
Cost to replace an unvented hot water cylinder, e.g., Megaflo £305
Cost to fit thermostatic radiator valves (TRVs) £94
Cost to fit smart heating controls £100
Cost to fit a radiator £80
Boiler service cost £90
Boiler repair costs (e.g. pump, diverter valve or heat exchanger) £333
Cost to install an air source heat pump £556
Replacement of a vented system £580

Rates for other trades

Powerflush cost in the UK
Powerflush cost in the UK (excluding VAT or callout charges)
Location in UKPowerflush cost
Powerflush near Aberdeen£568
Powerflush near Amber Valley£482
Powerflush near Angus£540
Powerflush near Arun£546
Powerflush near Ashfield£478
Powerflush near Aylesbury Vale£562
Powerflush near Barnsley£468
Powerflush near Basildon£528
Powerflush near Basingstoke & Deane£546
Powerflush near Bassetlaw£490
Powerflush near Bath & North East Somerset£520
Powerflush near Bedford£566
Powerflush near Belfast£424
Powerflush near Birmingham£466
Powerflush near Blackburn£474
Powerflush near Blackpool£500
Powerflush near Bolton£498
Powerflush near Bournemouth£542
Powerflush near Bracknell Forest£574
Powerflush near Bradford£470
Powerflush near Braintree£516
Powerflush near Breckland£484
Powerflush near Bridgend£452
Powerflush near Brighton£526
Powerflush near Bristol£506
Powerflush near Broadland£534
Powerflush near Broxtowe£474
Powerflush near Bury£494
Powerflush near Caerphilly£452
Powerflush near Calderdale£460
Powerflush near Cambridge£550
Powerflush near Canterbury£490
Powerflush near Cardiff£464
Powerflush near Carmarthenshire£398
Powerflush near Charnwood£460
Powerflush near Chelmsford£518
Powerflush near Cheltenham£620
Powerflush near Cherwell£554
Powerflush near Chester£438
Powerflush near Colchester£510
Powerflush near Conway£408
Powerflush near Coventry£468
Powerflush near Crewe & Nantwich£474
Powerflush near Dacorum£560
Powerflush near Derby£460
Powerflush near Doncaster£486
Powerflush near Dover£468
Powerflush near Dudley£468
Powerflush near Dumfries & Galloway£504
Powerflush near Dundee£548
Powerflush near East Ayrshire£380
Powerflush near East Devon£494
Powerflush near East Dunbartonshire£570
Powerflush near East Hampshire£538
Powerflush near East Hertfordshire£554
Powerflush near East Lindsey£438
Powerflush near East Riding£392
Powerflush near Eastleigh£560
Powerflush near Edinburgh£524
Powerflush near Elmbridge£584
Powerflush near Epping Forest£584
Powerflush near Erewash£466
Powerflush near Exeter£514
Powerflush near Falkirk£550
Powerflush near Fife£522
Powerflush near Flintshire£452
Powerflush near Gateshead£520
Powerflush near Gedling£470
Powerflush near Glasgow£558
Powerflush near Gloucester£644
Powerflush near Guildford£592
Powerflush near Gwynedd£464
Powerflush near Halton£472
Powerflush near Harrogate£456
Powerflush near Havant & Waterloo£532
Powerflush near Highland£640
Powerflush near Horsham£536
Powerflush near Huntingdonshire£542
Powerflush near Ipswich£606
Powerflush near Isle of Wight£524
Powerflush near Kings Lynn & West Norfolk£520
Powerflush near Kingston-upon-Hull£392
Powerflush near Kirklees£456
Powerflush near Knowsley£464
Powerflush near Lancaster£540
Powerflush near Leeds£460
Powerflush near Leicester£464
Powerflush near Lisburn£424
Powerflush near Liverpool£464
Powerflush near London£578
Powerflush near Luton£574
Powerflush near Macclesfield£490
Powerflush near Maidstone£510
Powerflush near Manchester£482
Powerflush near Mid Bedfordshire£556
Powerflush near Mid Sussex£548
Powerflush near Middlesbrough£490
Powerflush near Milton Keynes£564
Powerflush near Neath Port Talbot£468
Powerflush near New Forest£538
Powerflush near Newbury£548
Powerflush near Newcastle-under-Lyme£452
Powerflush near Newcastle-upon-Tyne£524
Powerflush near Newport£468
Powerflush near North Ayrshire£448
Powerflush near North East Lincolnshire£508
Powerflush near North Hertfordshire£560
Powerflush near North Lanarkshire£562
Powerflush near North Lincolnshire£442
Powerflush near North Somerset£496
Powerflush near North Tyneside£518
Powerflush near North Wiltshire£620
Powerflush near Northampton£550
Powerflush near Norwich£520
Powerflush near Nottingham£460
Powerflush near Nuneaton & Bedworth£464
Powerflush near Oldham£488
Powerflush near Oxford£562
Powerflush near Pembrokeshire£408
Powerflush near Perth & Kinross£540
Powerflush near Peterborough£548
Powerflush near Plymouth£492
Powerflush near Poole£540
Powerflush near Portsmouth£526
Powerflush near Powys£616
Powerflush near Preston£498
Powerflush near Reading£576
Powerflush near Redcar & Cleveland£472
Powerflush near Reigate & Banstead£582
Powerflush near Renfrewshire£536
Powerflush near Rhondda, Cynon, Taff£432
Powerflush near Rochdale£488
Powerflush near Rochester-upon-Medway£560
Powerflush near Rotherham£474
Powerflush near Salford£480
Powerflush near Salisbury£502
Powerflush near Sandwell£464
Powerflush near Scarborough£484
Powerflush near Scottish Borders£740
Powerflush near Sefton£464
Powerflush near Sevenoaks£534
Powerflush near Sheffield£484
Powerflush near Slough£580
Powerflush near Solihull£466
Powerflush near South Ayrshire£454
Powerflush near South Bedfordshire£566
Powerflush near South Cambridgeshire£530
Powerflush near South Gloucestershire£512
Powerflush near South Kesteven£544
Powerflush near South Lanarkshire£552
Powerflush near South Oxfordshire£548
Powerflush near South Somerset£526
Powerflush near South Tyneside£518
Powerflush near Southampton£554
Powerflush near Southend-on-Sea£510
Powerflush near St Albans£578
Powerflush near St Helens£462
Powerflush near Stafford£476
Powerflush near Stockport£486
Powerflush near Stockton-on-Tees£494
Powerflush near Stoke-on-Trent£452
Powerflush near Stratford-on-Avon£492
Powerflush near Stroud£576
Powerflush near Suffolk Coastal£640
Powerflush near Sunderland£518
Powerflush near Swale£504
Powerflush near Swansea£456
Powerflush near Tameside£482
Powerflush near Teignbridge£504
Powerflush near Tendring£574
Powerflush near Test Valley£522
Powerflush near Thamesdown£620
Powerflush near Thanet£510
Powerflush near The Wrekin£508
Powerflush near Thurrock£530
Powerflush near Torbay£500
Powerflush near Trafford£488
Powerflush near Vale of Glamorgan£460
Powerflush near Vale of White Horse£570
Powerflush near Vale Royal£448
Powerflush near Wakefield£470
Powerflush near Walsall£464
Powerflush near Warrington£490
Powerflush near Warwick£482
Powerflush near Waveney£506
Powerflush near Waverley£570
Powerflush near Wealden£540
Powerflush near West Lancashire£470
Powerflush near West Lothian£552
Powerflush near West Wiltshire£620
Powerflush near Wigan£474
Powerflush near Windsor & Maidenhead£578
Powerflush near Wirral£458
Powerflush near Wokingham£578
Powerflush near Wolverhampton£466
Powerflush near Wrexham Maelor£582
Powerflush near Wychavon£530
Powerflush near Wycombe£590
Powerflush near York£456