Blocked Central — Heating Pipes Link

In extreme cases where sludge has solidified over many years—often referred to as "concrete"—or where limescale has fused to the pipe walls, the pipework may need to be physically cut out and replaced.

I don;t know which is best, but I understand the latest ones work by both magnetic and 'swirling' out sediment (like a Dyson). It' Screwfix Community Forum blocked central heating pipes

: In older systems with loft tanks, the junction where the feed pipe joins the main circuit is a primary spot for blockages. In extreme cases where sludge has solidified over

Prevention is invariably more cost-effective than cure. Prevention is invariably more cost-effective than cure

: Unusual banging, "kettling," or gurgling sounds from the boiler or pipes.

For minor blockages, chemical cleaning agents can be added to the system via the radiator or a filling loop. These chemicals break down sludge and scale, allowing them to be dispersed. However, this is often a temporary fix for heavily blocked systems.