Up to 8 radiators
Fixed price
Standard combi or system boiler. MagnaCleanse process, X100 inhibitor refresh, certificate — quoted before work starts.
Plumbing Services
Power Flushing in Corbycold radiators back to fully hotin a single day, fixed price
If radiators are cold at the bottom, your boiler clicks off and on, or your heating bills have crept up — sludge in the system is the usual cause. We power-flush with MagnaCleanse and full inhibitor refresh, in a day, for one fixed price.
- Completed in a single day
- MagnaCleanse-grade kit
- Inhibitor refresh included
- 12-month workmanship guarantee
1 day
Average job time
20+°C
Typical radiator temp gain
Up to 25%
Heating efficiency recovered
12 mo
Workmanship guarantee
Power flushing — combi, system & open-vented
What a proper power flush actually does — and what it doesn't
A power flush forces water and a chemical cleaner through your central heating system at high velocity but low pressure, breaking up the magnetite sludge and limescale that's coating the inside of your radiators and pipework. Done properly, you get hot radiators top-to-bottom, faster heat-up, lower gas consumption and a quieter boiler.
Done badly — too low pressure, too short a dwell time, no proper neutraliser, no inhibitor refresh — it's barely better than a manual drain-down. We use the MagnaCleanse process, dwell each radiator individually, and refill with fresh inhibitor at the manufacturer-specified concentration. Every job ends with a TDS (total dissolved solids) reading to prove the system is genuinely clean.
It is not a fix for: undersized radiators, frozen condensate pipes, faulty diverter valves, or boilers at end of life. We'll tell you honestly during the survey whether a flush will solve your symptom — or whether something else needs sorting first.
What happens if you wait
Sludge isn't a maintenance issue — it's an efficiency tax
Magnetite sludge builds up in every wet central heating system. After 8–12 years it lines the inside of every radiator, narrows pipework bores, blocks heat exchangers and forces your boiler to work harder for the same heat. The cost is invisible — until you compare bills before and after a flush.
Worse, sludge accelerates boiler component failure: pumps seize, diverter valves stick, plate heat exchangers block, and warranty claims get rejected because the system wasn't kept clean.
- Cold spots at bottom of radiators (sludge) or at the top (air)
- Boiler kettling — banging or whining as sludge restricts flow
- Heat-up time noticeably longer than 5 years ago
- Boiler manufacturer warranty rejected for 'system contamination'
- Pump or diverter valve replaced more than once in 5 years
- Black water when bleeding radiators — that's iron oxide, i.e. sludge
Our process
From first call to job done — exactly what to expect
- 01
Survey & test
MagnaCleanse-style flow test on each radiator + system water TDS sample. We confirm a flush will help before quoting.
- 02
Pre-treatment
Cleaning chemical added, system circulated for 1–2 hours to lift bonded scale and break up magnetite.
- 03
Power flush
Each radiator individually dwelled and reverse-flushed. Magnet captures iron oxide as it leaves.
- 04
Neutralise & refill
System neutralised, refilled with fresh water, dosed with inhibitor at manufacturer-specified concentration.
- 05
Test & certify
Pre/post TDS readings, radiator surface temperature differentials, written certificate for warranty records.
Why customers choose Reactive
No guesswork. No upsell. Just the work, done right.
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Cuts heating bills
Restored radiator output means shorter run times. Customers report 10–25% gas savings post-flush.
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Protects boiler warranty
Most warranties require system cleanliness. Our written certificate satisfies manufacturer requirements.
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Done in a single day
Standard 8-rad system flushed and back in service same day. We don't drag it out across visits.
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MagnaCleanse process
Industry-recognised cleaning method with proper dwell times — not a quick mains-pressure flush.
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Inhibitor refresh included
Sentinel X100 (or equivalent) at manufacturer-spec dose. Without this, sludge re-forms within 2 years.
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Honest 'don't bother' if it won't help
If your symptom is undersized rads or a failing pump, we'll tell you before you pay for a flush you don't need.
In detail
What's actually inside your heating system — and why it matters
The black goo that comes out when you bleed an old radiator is magnetite — iron oxide formed by the corrosion of steel radiator panels in oxygen-rich water. Every wet central heating system creates it. Inhibitor (Sentinel X100, Fernox F1, etc.) suppresses corrosion but degrades over time and gets washed out when the system is opened up for repairs.
By 8 years post-installation, an unmaintained system typically has 3–5kg of sludge sitting in radiators and low points of the pipework. By 12 years, that figure can double. The sludge isn't dangerous, but it kills heating efficiency: a sludged radiator might output 60% of its rated kW, meaning the boiler runs 40% longer to compensate.
Power flushing is the only effective way to remove bonded magnetite once it's built up. Magnetic system filters (MagnaClean, Adey ProTwo) catch new magnetite as it forms, but they can't shift what's already settled. Best practice: flush at install, fit a magnetic filter, refresh inhibitor every 5 years, service annually.
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Combi boiler systems
Plate heat exchangers are most vulnerable to sludge — flushing pre-empts costly PHE replacement.
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System & open-vented
Larger water content, more sludge accumulates over time. Flushing is more involved but more impactful.
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Underfloor heating
UFH manifolds need careful flushing — we flush per-loop, not whole-system blast.
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Old cast-iron radiators
Heritage rads can be flushed but need extra care on dwell pressure. We've done plenty in Oundle and Stamford.
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Magnetic filter fitting
MagnaClean Pro2 fitted at the same time — captures any future magnetite before it settles in radiators.
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Inhibitor regimen
Sentinel X100 / Fernox F1 at install dose. Re-test inhibitor concentration at every annual service.
Honest pricing
How much does a power flush cost in Corby & Northants?
Pricing is per number of radiators on the system. Includes pre-clean, full power flush, neutraliser, fresh inhibitor and a written cleanliness certificate.
9–12 radiators
Fixed price
Larger family home or extended system. Same process, longer dwell, larger inhibitor dose.
13+ radiators or commercial
Quoted on survey
Site survey first. Includes mid-rinse flush stage and per-zone isolation as needed.
What changes the price
- Number of radiators on the system
- System type (combi, system, open-vented, sealed)
- Severity of sludge (light, moderate, heavy)
- Whether a magnetic filter is being fitted at the same time (supplied & fitted as a fixed-price add-on)
- Access to the boiler and radiators
- Whether old cast-iron radiators need extra-careful low-pressure dwell
Free, fixed-price quote — no obligation, no callout fee.
Get my fixed priceAreas covered
Local cover across Northants & Rutland
Power flushing is a particularly common ask across the older housing stock in Corby town centre, the village stone properties around Oundle and Oakham, and the Kettering 1990s estates that are now reaching the 20-year sludge tipping point. We cover all of it from the same fixed-price model.
Who'll be doing the work
The Reactive engineering team
our team runs every flush personally with a stocked van — pump, magnet, neutraliser, inhibitor and TDS meter. We don't sub-flushes out — they go wrong too easily when handed to someone with rented kit and no follow-up incentive.
- Gas Safe Registered
- OFTEC Registered
- MagnaCleanse trained
- Manufacturer-approved chemical regimen
- 12-month workmanship guarantee
FAQs
Questions we actually get asked
Anything not covered here? Pick up the phone — straight talk, no salesperson in the middle.
Call 07342 043953Ready when you are
Cold radiators? Whining boiler? Flush it.
MagnaCleanse-grade flush, full inhibitor refresh, written certificate — completed in a single day for one fixed price.
Last updated May 2026 · Reactive Gas Heating and Plumbing Services Limited · 9 Rutherford Court, Corby NN17 4SJ · Gas Safe Registered · OFTEC Registered · Checkatrade Verified