These systems are slightly easier to power flush and tend to have less sludge because they are sealed from the atmosphere (oxygen). The procedure is straight forward for the radiators. When you flush the boiler it is important NOT to operate the hot water while doing so, as the diverter valve can get stuck or damaged.

The common optional extras on power flushing this type of system:

• It is important to know that if you are having hot water problems on these systems, you might need to have the hot water heat exchanger, physically removed and flushed/de-scaled separately.
• Changing radiator valves