How power flushing actually works
A power flush isn't 'high pressure', it's high flow, low pressure. An industrial pump (we use the Kamco CF210) pushes 150 litres of dosed water per minute through your system in reversible directions, dislodging magnetite that's settled at the bottom of radiators and inside heat exchangers. The flow is gentle on joints but aggressive on sludge. Combined with a heavy-duty descaler and sludge dispersant, even systems left untouched for 20 years come back to clear water by the end of the day.
Why magnetite forms in the first place
Every steel radiator slowly corrodes when in contact with oxygenated water. The corrosion produces iron oxide, magnetite, which is heavier than water and settles to the bottom of radiators and pipe low points. A working inhibitor (Sentinel X100, Fernox F1) suppresses corrosion to near zero, but inhibitor depletes after 12–18 months. Most homeowners never top it up, and within 5–8 winters the system is sludge-loaded.
Power flush vs chemical flush vs MagnaCleanse
A chemical flush is a non-mechanical clean, cleaner added, system run for an hour, then drained. It works only on lightly soiled systems. A MagnaCleanse uses a powerful in-line magnet plus dispersant, good for boiler-swap protection but not deep cleaning. A full power flush uses an industrial pump plus chemicals plus per-radiator agitation, the only method that restores a heavily sludged system.
Hard water and St Albans
Hertfordshire sits on chalk aquifer, water hardness in St Albans, Watford and Barnet typically reads 280–340 ppm CaCO₃. That's hard. Hard water means limescale on the boiler's heat exchanger as well as magnetite in the radiators. We dose for both during the flush, and recommend a scale reducer at the boiler return for any home north of the M25.
When a flush isn't enough
A handful of systems are too far gone, radiators perforated by internal corrosion, pipework restricted by decades of scale, or pin-hole leaks waiting to open. We'll tell you on the survey if a flush will solve the problem or if individual radiators need swapping first. We won't take £600 for a flush that won't fix it.
