‘POWER FLUSHING’, ‘JET FLUSHING’ & ‘HARD FLUSHING’…
…are all expressions used in the heating trade to describe the process by which heating systems are forcibly cleansed using water at high velocity but low pressure – so that no physical damage is caused to the system.
The objective is to restore systems with circulation and boiler noise problems to optimum operation (these problems are typically caused by sludge and corrosion deposits). Power flushing removes these deposits and eliminates the associated problems.
Power flushing is an excellent way to
- pre-commission clean new heating systems
- remove excess flux, and other debris
- remove the grease and oil used to prevent rusting of components before use
It is prudent to power flush a heating system immediately before fitting a new boiler to an existing system to prevent possible future problems. Many systems are found to contain corrosion and sludge – even if no flow problems have yet shown themselves.
Existing debris is often mobilized by alterations to the system/piping and the increased efficiency of the new boiler. This debris may then accumulate in the boiler heat exchanger, causing noisy operation, reduced efficiency and, in extreme circumstances, failure of the boiler. The high efficiency and compactness of modern boilers, developed to minimize fuel costs and pollution, means that they are more susceptible to problems caused by debris in the system water.
In hard water areas, the use of water in heating and cooling systems invariably results in a build up of lime scale (hard water) deposits within the system, usually in the highest temperature zones. The resultant scale not only restricts water flow, but acts as a very effective insulant, reducing heat transfer efficiency and increasing running costs.
Heavy scale deposits can also lead to localized overheating of heat transfer surfaces, resulting in premature failure of heating appliances.
In all areas, rust and corrosion may take place in heating and cooling systems, leading to a build up of corrosion deposits and a reduction in efficiency.