Whilst it is rare for a central heating system to experience leaks after the power flushing process, it is not possible to inspect a system internally before hand, and the need to use a flushing and dispersing chemical for effective cleaning means that occasionally we may find a leak.The advanced stage of corrosion required for such a situation means that the leak would occur imminently even without a power flush. We believe that it better that it occurs whilst we are present to remedy the problem, rather than for it to arise over a weekend whilst the house may be unoccupied.