With all of the dissimilar metals used in heating systems (copper, steel, cast iron, brass, aluminium etc) plus the added water, electrolytic corrosion can take place and ultimately damage your system,
As you can see on these two separate photos, the white speedfit pipe is fully blocked and the copper pipe is badly restricted,
In both cases the customer wasn’t getting any heat to the affected radiators and partial heat to many other radiators.
When a system is “sludged” up like this it also puts a strain on the boilers heat exchanger, cylinder coil, pumps, motorised valves and air vents.
This is where a power flush is needed to get rid of as much of the debris as possible to ease circulation. When a new boiler is fitted a power flush is a must to help prolong the life of the boiler and fitted components, a magnetic filter added to the system can also help catch the “magnatite” plus be cleared on an annual basis.