When assessing an existing heating system, physical manifestations found as a result of sludge and corrosion debris being present are a good indication. These may be:

  1. The system is slow to warm up.
  2. Some radiators are completely or partially cold when the system is operational.(a heating engineer may use an infra-red thermometer or camera to assess the degree of fouling.)
  3. The radiators are not getting very hot even with the valves on maximum, but the pipe work running to the radiators IS hot.
  4. The radiators need frequent bleeding as a result of gas generation.(hydrogen gas is a by-product of the corrosion process.)
  5. Water samples taken from radiators are dirty and discoloured.
    1. If there are black particles present in the water (see Diagram 1), these are most likely to be magnetite. As this is the final stage of corrosion, large deposits can be expected within the system.
    2. If there is a reddish tinge to the water, it indicates that iron oxide is present, suggesting active corrosion.
  6. One or more radiators have failed with pin hole perforations.
  7. There are ‘kettling’ noises from the boiler.
  8. The circulator pump is found to be heavily fouled and frequently needs replacing.

How does power flushing work
Power flushing is considered to be the most effective method of cleaning systems currently available (see (BS7593). Power flushing is done by a large pump that is connected to the heating system. If it’s a Combi it will be connected at the pump head but if it’s a System boiler it will be connected at the circulation pump. This pump will push special chemicals through the pipes, boiler and radiators.

This includes a chemical that will remove sludge and rust, a descaler to remove limescale and corrosion inhibitor to help prevent future rust from forming. To help speed the process some of these chemicals I may add some a day or two before.

The engineer may also use special tools on the exterior of the radiator to dislodge stubborn blockages. They should be able to measure the temperature of your radiators before they have started work and then show you the improvement after the Powerflush.

The whole process can last anything from 6 hours to 2 days depending on the number of radiators in your home, the age of the system and the severity of the sludge in the system. The engineer may find more problems than originally anticipated such as needing new parts to replace those that have been damaged beyond repair. Most Powerflush jobs can be completed in one day but some of the more severe cases may require longer.

How Much Will a Powerflush Cost?

There are lots of factors that will affect the price of a Powerflush such as size and complexity of the heating system, not to mention any incidental troubleshooting that crops up. A Powerflush can cost anything between £300 to £1000+. Sometimes there will be additional costs like extra descaler chemicals or replacing the TRVs.

It’s important that your central heating system is as efficient as it can be at all times and, although a Powerflush can be an expensive process, it can also save a lot of money over time in reduced heating bills.

What to do after a power flush
Inhibitor is added to prevent further corrosion to the system. It’s a good idea to fit a magnetic cleaner such as the Magnaclean pro or twintech these will remove any further debris and help keep the system clean for years.