If you are tackling circulation problems, identifiable as cold spots in radiators, most often caused by sludge build-up. The formation of this sludge is almost impossible to completely prevent and it often settles in low flow areas of the system.
X400 High Performance Cleaner is the best central heating cleaner for this job as it breaks up, lifts and suspends this sludge, then allowing it to be flushed out of the system. In order to do this, it should be circulated, ideally at normal operating temperature, with all valves open and the pump set to maximum flow for a minimum period of 2 hours or until satisfactory performance is restored. In badly fouled systems, a period of circulation of up to 4 weeks is recommended
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