For detailed instructions on carrying out cleaning of central heating systems using DS40 Descaler & Cleaner and Neutraliser, please refer to the instruction leaflet inside the DS40 box. The product can be poured directly into a powerflushing unit; via the F&E tank or, in a sealed system, via a suitable dosing vessel into a radiator.One bottle of System Neutraliser (2L) is usually sufficient to neutralise one bottle of DS40 Descaler & Cleaner (1.5 kg) after cleaning the central heating system. The system water (after allowing any debris to settle) should be yellow in colour. If the water is still red, more neutraliser will need to be added. The system must be drained down and flushed several times with fresh water until the water running to drain is clear. After the final drain, it is recommended that the system is inhibited using a suitable Fernox Protector. In single feed indirect cylinders, e.g. ‘Primatic’ systems or similar, potable water chemicals must be used.