It is recommended that Corgi TripCon Silencer is added to the system together with Corgi TripCon Inhibitor to give maximum protection|Both products can be left in the system indefinitely|Corgi TripCon Silencer is designed to reduce boiler noise in central heating systems caused by lime scale deposited onto the boiler heat exchanger|It is suitable for all types of systems including those containing aluminium|Directions: For use in indirect systems only|For open vented systems fill via header tank|For sealed systems fill via a radiator