Power Flush Streatham & South London
Looking for a power flush in Streatham or South London? MAK Plumbing & Heating are Gas Safe registered engineers specialising in central heating power flushing across Streatham, Balham, Tooting, Clapham, Brixton and all surrounding SW postcodes. We remove black magnetite sludge from your heating system to eliminate cold radiators, stop boiler noise and restore efficiency. Power flush prices from £380 — call 07900 247 384 for a free assessment.
Power Flush Streatham & South London
We remove the black sludge destroying your boiler — leaving you with warmer rooms, lower bills, and a heating system that actually works.
Real magnetite sludge removed from a South London heating system
caused by sludge
from magnetite build-up
on energy bills after a flush
Is Your Heating System Showing Any of These Signs?
These are the warning signs of sludge and magnetite build-up. The more you recognise, the more your system needs a power flush.
Sludge settles at the lowest points and blocks heat transfer — the classic symptom.
Scale and sludge on the heat exchanger causes localised boiling and noise.
Uneven distribution of sludge across the system causes inconsistent heating.
Restricted flow means hot water takes far longer to reach radiators.
Discoloured water is magnetite in suspension — a direct sign of heavy contamination.
A dirty system uses significantly more fuel to reach the same temperature.
Sludge starves the heat exchanger of flow, triggering overheat lockouts.
Magnetite particles destroy pump impellers — replacing the pump without flushing guarantees the new pump will fail too.
Recognise any of these? Call us today for a free, no-obligation assessment.
What Is a Power Flush — and What Is Magnetite?
A power flush is a deep clean for your central heating system. Over time, the water circulating through your pipes and radiators corrodes the steel inside them. The result is magnetite — a fine black iron oxide powder that builds up into a thick, sticky sludge.
Left untreated, this sludge restricts water flow, forces your boiler to work far harder than it should, and eventually destroys pumps, valves and heat exchangers. In South London — where the water is among the hardest in England — limescale compounds the problem by furring up the inside of your boiler’s heat exchanger.
A power flush machine pushes a powerful chemical cleaning solution through your entire system at high velocity, dislodging and expelling all the accumulated sludge. The contaminated water is removed and replaced with clean water and a long-life inhibitor to prevent future corrosion.
What Does a Power Flush Involve?
Here is exactly what we do, step by step. No jargon — just a clear explanation of what happens in your home.
System Assessment
We test the water quality, inspect all radiators and check the boiler. We advise you honestly on what the flush will achieve before starting any work.
Preparation & Connection
Dust sheets are laid down. The power flush machine connects to your system via the pump head or a radiator valve — no cutting of pipes required.
Chemical Dosing
A specialist sludge-dispersing and descaling chemical (Fernox DS40 or Sentinel X400) is added and circulated at high velocity through the whole system.
Radiator-by-Radiator Flush
Each radiator is isolated and flushed individually, with flow alternated forward and reverse. Each is physically vibrated to dislodge compacted sludge from corners and fins.
Full System Rinse
The system is flushed repeatedly with clean mains water until the expelled water runs completely clear. All contaminated water is safely removed and disposed of.
Inhibitor & Magnetic Filter
Fresh water fills the system and a long-life corrosion inhibitor is added. A magnetic filter is fitted or checked on the boiler return to capture any future particles.
Test, Balance & Certificate
The boiler is fired up, all radiators are checked for even heat distribution, system pressure is verified and we issue a completion certificate.
Benefits of a Power Flush
A single day’s work that pays for itself in efficiency savings and avoided breakdowns.
Improved Efficiency
Clean systems can recover 7–40% efficiency lost to sludge. Your boiler reaches target temperature faster using less fuel.
Lower Energy Bills
Homeowners typically save £60–£112 per year on gas bills after a power flush. The flush pays for itself within a few years.
Warmer Rooms, Evenly
All radiators reach full temperature. Cold spots, cold rooms and uneven heating are eliminated.
Extended Boiler Life
Removing corrosive sludge is the single best thing you can do to extend your boiler’s working life and avoid premature replacement.
Quieter System
Eliminates the banging, kettling and gurgling noises that sludge and scale cause on the heat exchanger.
Fewer Breakdowns
Sludge causes 60% of boiler breakdowns. Removing it dramatically reduces your risk of expensive emergency callouts.
Power Flush Cost in Streatham & South London
We publish our prices openly — no hidden charges, no surprises. All prices include corrosion inhibitor, system test and a completion certificate.
Prices shown are typical for South London. Heavily contaminated systems may take longer — we advise before starting.
| Property | Radiators | Duration | Price (inc. VAT) |
|---|---|---|---|
| Studio / 1-bed flat | 3–4 | 3–5 hours | From £380 |
| 2-bed flat or house | 5–7 | 4–6 hours | From £430 |
| 3-bed house Most common | 8–10 | 5–8 hours | From £480 |
| 4-bed house | 11–15 | 6–9 hours | From £580 |
| 5+ bed / large property | 15+ | 1–2 days | Call for quote |
All prices include: corrosion inhibitor dose, magnetic filter check, system pressure test, and a signed completion certificate. Magnetic filter supply and installation (if not already fitted) from £90 extra — strongly recommended and required by most boiler manufacturers.
Not sure which applies to you? Call or WhatsApp and we’ll give you an accurate quote.
Do I Need a Power Flush Before a New Boiler?
In most cases, yes. Under British Standard BS 7593:2019, central heating systems must be cleaned and treated before or when a new boiler is installed.
Every major boiler manufacturer — Worcester Bosch, Vaillant, Ideal, Baxi — requires system cleanliness as a condition of their warranty. Fitting a new boiler into a sludge-contaminated system is the fastest way to invalidate a costly warranty and damage a brand-new appliance.
We carry out power flushes as part of new boiler installations and as standalone services. If you’re planning a new boiler — always flush first.
Boiler Manufacturer Requirements
Power Flush FAQs
Common questions from South London homeowners.
Is a power flush guaranteed to fix my heating problems?
A power flush resolves the vast majority of sludge-related problems — cold radiators, noisy boilers, slow warm-up times. However, if components such as the pump or heat exchanger have already been mechanically damaged by years of sludge, those parts may also need replacing. We carry out an assessment before starting and advise you honestly on what the flush will achieve.
Do I need a power flush before fitting a new boiler?
Yes, in most cases. Under British Standard BS 7593:2019, central heating systems must be cleaned before or when a new boiler is installed. Most boiler manufacturers will void your warranty if the system was not properly cleaned at installation. Fitting a new boiler into a contaminated system is the fastest way to damage an expensive new appliance.
Can a power flush damage old pipes?
A properly performed power flush uses high flow but low pressure — it will not damage pipework that is in sound condition. If pipework is severely corroded or has existing weak joints, we identify this during the initial assessment and advise you before starting any work.
How long does a power flush take?
For a typical 3-bedroom South London property with 8–10 radiators, expect a full day (5–8 hours). Smaller flats with 4–6 radiators can be completed in 4–5 hours. Heavily contaminated systems take longer — we give you an accurate estimate after the initial assessment.
How often should I power flush my central heating?
Most engineers recommend every 5–6 years. If you have a magnetic filter fitted — which we strongly recommend — this can extend to every 6–10 years as the filter captures future magnetite particles before they build up. If your system has never been flushed and is more than 5 years old, it is overdue.
What happens after a power flush — will my system stay clean?
We dose the system with a long-life corrosion inhibitor and recommend fitting a magnetic filter to the boiler return pipe if one is not already present. The inhibitor and filter work together to prevent sludge rebuilding — keeping your system clean for years after the flush.
Do I need to be home all day?
Yes — we need access to all radiators throughout the property and the boiler for the full duration of the job. We give you a start time in the morning and keep you informed of progress throughout. Most 3-bed properties are finished within a single working day.
Power Flush Streatham & All South London Areas
We cover Streatham and all surrounding areas across South and South West London. Based in SW16, we typically arrive within the same week of booking.
Not listed? We likely cover your area — call 07900 247 384 to check.
Book Your Power Flush in Streatham Today
Don’t wait until your boiler breaks down. Call Michael now for a free, no-obligation assessment — available Monday to Saturday, most jobs booked within the same week.
Gas Safe registered · #939043 · BS 7593:2019 compliant · Completion certificate issued