Everbuild Central Heating P11 System Cleanser Concentrate will remove commissioning & flux residues from new systems & restore circulation to old systems which suffer from sludge. Everbuild P11 System Cleanser should also be used when components are replaced or existing systems are extended. This product is compatible with plastic tanks, micro bore & all metals (including aluminium) used in central heating systems. It is very economical as 310 ml will treat a 70 litre system capacity in new & existing central heating systems or extensions to existing systems. Size: 310ml (C3).