Power flushing: cleaning sludge from your radiators
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It’s essential to keep your radiators working correctly, so they can keep you warm through the winter. If you’re having problems with your heating, your radiators might need a power flush.
Several symptoms may indicate you need a power flush.
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Some radiators are completely or partially cold
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Radiators need to be frequently bled
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Repeated pump failures/corrosion deposits in the pump casing
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`Kettling' and banging noises from the boiler
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Long recovery time after drawing off hot water
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Sludge may also be to blame if some radiators aren’t heating while others are working properly.
You’ll find information below about the causes of sludge in your central heating system. We’ll also explain the power flushing process.
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Why is there sludge in the radiator?
The older your central heating system is, the more likely it is that you have sludge in your radiators.
Blocked radiators raise your bills, as your heating has to work harder to warm your home. Sludge can also damage your boiler, heat pump and valves.
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Radiator sludge is a mix of dirt and rust. This builds up over time and gathers at the bottom of your radiators.
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The sludge stops hot water from flowing through your system correctly. This creates cold areas on your radiator.
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Other areas of the radiator are unaffected by the sludge and warm up as normal.
How does power flushing work?
If you think sludge is blocking your radiators, get a Heating engineer to take a look.
If you need a power flush, the engineer will connect a machine to your system. This will drive a high-flow, low-pressure liquid through your system. This dislodges sludge and rust, removing them from your radiators, pipes, and boiler.
It can take several hours to flush out your heating system. It can take even longer if you have a larger system or there’s a lot of sludge.
The cleaned central heating system must be treated with the chemical inhibitor immediately following cleaning. The inhibitor will minimise metal corrosion within the system and prevent limescale formation. This will ensure that design energy efficiency is maintained, and replacement of components due to corrosion and erosion is minimised.
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References
BS EN 12828 and BS EN 12831 Hot water central heating system for domestic premises England, Wales, Scotland, Northern Ireland and the Republic of Ireland.
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BS 7593: Code of Practice for the treatment of water in domestic hot water central heating system
