A high-performance, non-acid cleaner specifically designed for older central heating systems. This powerful formula restores circulation to radiators and pipework by efficiently removing built-up magnetite sludge. It effectively eliminates cold spots in radiators and improves overall heat distribution, leading to better system efficiency and fuel conservation. Sentinel X400 is suitable for preparing existing systems for new components like boilers, pumps, or radiators and can treat systems with 8-10 radiator panels. It does not cause pin holing or leaks.