Power flushing · Cork
Power flushing to restore the efficiency of your heating system.
Over the years a heating system fills with black sludge — rust and magnetite from inside the radiators and pipes. It settles at the bottom of radiators, blocks valves and the boiler heat exchanger, and makes the whole system work harder. A power flush pushes it out; a magnetic filter and inhibitor help stop it building up again.
In short
Radiators that are cold at the bottom, a noisy boiler and dark water when you bleed a radiator usually mean sludge in the system. A power flush pushes the sludge out, and a magnetic filter and inhibitor help stop it building up again. Most houses are done in a day.
Updated 18 October 2026 · C. Kenneally Heating & Plumbing
Signs of sludge
Signs your system needs cleaning.
Radiators cold at the bottom
Warm at the top and cold at the bottom is the classic sign.
Read more →Black water when you bleed
Dark, dirty water from the bleed valve means magnetite in the system.
Boiler banging or kettling
Sludge and scale on the heat exchanger make the boiler noisy.
Some rooms never warm up
Partly blocked radiators and valves starve parts of the house.
Fitting a new boiler
Why we clean the system before fitting a new boiler.
Read more →Before a heat pump
Heat pumps run at lower temperatures and need a clean system.
How it works
How a power flush works.
- 01
Check the system
We test the water, check the boiler and radiators, and agree the price.
- 02
Flush
A flushing pump and cleaning chemical are run through each radiator in turn.
- 03
Protect
Clean water, inhibitor added and a magnetic filter fitted.
- 04
Balance
Radiators bled and balanced so every room heats evenly.
Questions
Frequently asked questions
Will a power flush fix a cold radiator?
If the cause is sludge, usually yes. If it is a stuck valve, an air lock or an undersized radiator, we will say so and fix that instead.
How long does it take?
Most houses are done in a day.
Book a service or request a quote.
Book a service or ask for a price online, and attach a photo of the boiler, the leak or the job. Christy replies with a fixed price or a time to call, and nothing starts until you have agreed it.
RGI registered · OFTEC registered · SEAI registered · Public liability insured · Cork City & surrounding area