A power flush, is typically a process used to clean out and remove sludge, rust, debris, and other contaminants from central heating system. This should be done before changing your heating system, in this instance when changing an oil or gas boiler to an Airsource heatpump.

Generally speaking this is what you can expect to happen:


1. System Preparation

The heating system is drained of water and a flushing machine connected

2. Chemical Treatment

We then add a cleaning chemical solution to the system. This solution helps to break down and loosen debris, sludge, and rust that have accumulated inside the pipes, radiators, and boiler.

3. Circulation

The flushing pump circulates the cleaning solution throughout the heating system at high velocity, dislodging and suspending the debris. If the radiators are particularly clogged up we will individually flush the radiators. This can be a time consuming process to carry out properly

4. Reverse Flow

In some cases, the flow direction might be reversed intermittently to dislodge stubborn deposits more effectively.

5. Removal of Contaminants

As the solution circulates, it carries the loosened debris and contaminants towards a collection point, typically a magnet or filter.

6. Rinsing 

After the system has been thoroughly flushed, it is then rinsed with clean water to remove any remaining traces of the cleaning chemical and suspended debris.

7. Inhibitor Addition

Once the system is clean, a corrosion inhibitor may be added to help protect the system from future corrosion and sludge build-up.


Many companies are not power flushing the system prior to the installation of an Airsource Heatpump. We would strongly recommend this is carried out as it can prevent cold spots on radiators, increase heat output, reduce energy consumption, and extend the lifespan of the system components.


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