Power Flushing

What is Power Flushing?

Power flushing is the most efficient method of cleansin a central heating system. The principle is to create a powerful fresh water flow under controlled conditions to remove debris from the system. By connecting the power flushing unit to the heating circuit in place of the system pump, boiler or radiator the circuit can be thoroughly cleansed of limescale and corrosion debris. When used in conjunction with a Fernox cleanser a typical power flush can be completed in 3-4 hours.

The problems

Fuel Wastage

Without treatment, corrosion debris will accumulate in the boiler causing increased limescale deposits, reduced heat transfer and up to a third of a fuel bill going to complete waste.

Boiler Noise

This increases in frequency and intensity as deposits of sludge and scale build up in an unprotected boiler.

Cold Spots

The familiar cool low central area of a radiator indicates a build-up of black sludge sediment that restricts flow and reduces heat.

Frequent Venting

When the top of a radiator is cold during operation, either air or hydrogen is to blame. Hydrogen gas builds up as a by-product of electrolytic corrosion and is flammable (due caution is required)

Pump Seizure and failure

The abrasive and magnetic properties of black oxide sludge increase shaft and bearing wear in pumps causing them to stick or fail.

The cleaning and treating of central heating systems

All new systems should be pre-commission cleansed in accordance with BS:7593 and Benchmark. This ensures flux residues, excess jointing compounds, mineral oil and other contaminants that can be found in the system following installation, and that can effect the performance of the system or cause component failure, are removed. It is important when installing new boilers into old systems that all sludge is first removed from the system or this could accumulate in the new boiler and lead to premature failure. Additionally, in hard water areas existing systems will have accumulated limescale together with corrosion deposits in the heat exchanger, which could easily have reduced the boiler efficiency by over 5%.

System Protection

Whether pre-commission cleaning new systems or restoring existing systems, all systems should be protected against any further attack from corrosion or limescale after cleansing by using a properly formulated corrosion and scale protector.


With over 30 years experience in the field of domestic water treatment Fernox have developed a range of products to help and maintain the efficiency of central heating systems and to ensure their long term protection against the damaging effects of corrosion and limescale.

As the original manufacturer of the very first power flushing unit - the squid - in 1987 Fernox have continually invested in research and development and have recently launched the new Powerflow flushing pump. With all the latest design features the Fernox Powerflow flushing unit will ensure a fast and effective system clean.

Fernox Restorers

Fernox Protectors