Power flushing in West London

Cold spots at the bottom of radiators, a boiler that bangs and kettles, slow warm-up? That is sludge in the system, and a power flush is what clears it.

• Full system flush with a pumping unit and magnetic filtration
• Every radiator cleared individually, not just the main circuit
• System re-dosed with corrosion inhibitor afterwards
• Magnetic system filter supplied and fitted where there is not one
• Usually completed in a single day
• Required by most manufacturers before a new boiler warranty starts

What sludge actually is

Steel radiators and water sitting together for years produce iron oxide, which is rust in suspension. It settles in the bottom of the radiators and in the low points of the pipework, where it stops water circulating. That is why a sludged radiator is hot across the top and stone cold along the bottom, and why the room never quite gets warm however long the heating runs.

The same debris ends up in the boiler's heat exchanger. Modern condensing boilers have narrow waterways, so they block far more easily than the old cast-iron units did, and a blocked heat exchanger is one of the most expensive parts on the boiler to replace.

How we do it

A pumping unit is connected to the system and pushes water through at high flow, with the direction reversed repeatedly to lift debris that has settled. A powerful magnet on the circuit catches the iron oxide as it comes loose. We work through the radiators one at a time rather than just flushing the main circuit, because the sludge sits in the radiators, not the pipes.

Once the water runs clear the system is re-dosed with corrosion inhibitor, which is what stops the whole process starting again. If there is no magnetic filter fitted we will recommend one, because it catches debris continuously between services and costs a fraction of what a new heat exchanger does.

Signs you probably need one

Radiators cold at the bottom but warm at the top. A boiler that bangs, kettles or knocks when the heating fires. Some radiators never heating while others are fine. Water that runs black when you bleed a radiator. A system that takes noticeably longer to warm the house than it used to.

West London's hard water makes all of this worse, because scale and sludge together are harder on a system than either alone. If the house has original radiators and nobody can remember the system ever being cleaned, it is worth a look.

Before a new boiler

Almost every manufacturer requires the system to be cleaned before a new boiler is commissioned, and they are entitled to refuse a warranty claim if it was not. Fitting a new boiler to a dirty system is the quickest way to ruin it. Where we are installing a boiler we will tell you honestly whether the system needs a full power flush or whether a chemical clean is enough, rather than adding it to every quote as standard.