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Powerflushing
Cold at the bottom, hot at the top, and a boiler that keeps cutting out — that is sludge, and a powerflush is what clears it.
Over the years a heating system fills with black iron oxide sludge. It settles in the bottom of radiators, blocks the narrow passages in a heat exchanger, and wears out pumps. The symptoms are radiators cold at the bottom, some that never warm at all, banging noises from the boiler, and a system that takes forever to heat up.
What a powerflush is
We connect a pumping unit to the system and push water through it at high velocity, in both directions, with a cleaning chemical. The debris comes out rather than settling somewhere else. It usually takes most of a day depending on the number of radiators.
Is it worth it
If your radiators are cold at the bottom, yes. If a boiler manufacturer has refused a warranty claim because of system contamination, definitely. If someone has told you every system needs one annually, no — that is not true and we will not sell you one you do not need.
For the longer explanation, read our guide to cold radiators, heating sludge and when powerflushing helps.
Before a new boiler
Most manufacturers require the system to be cleaned before a new boiler is fitted, and will not honour the warranty otherwise. If we are installing for you we will tell you whether yours needs it.
Keeping it clean
We fit a magnetic filter afterwards. It catches what forms next and is cleaned out at the annual service.
Call 07476 272447.
Frequently asked questions
What is a power flush?
A power flush is a deep clean of the central heating system, done by connecting a pumping unit and driving water through the pipes and radiators at high velocity with a cleaning chemical. It shifts the black iron oxide sludge that settles in the bottom of radiators and blocks heat exchangers. The debris leaves the system rather than moving to a different part of it.
How much does a power flush cost in the UK?
Usually £300 to £700 in the UK, priced mainly on how many radiators there are, since each one has to be worked on in turn. A six-radiator house sits near the bottom of that; twelve or more sits at the top. Anyone quoting a flat figure without asking the radiator count has not looked at the job.
What happens during a power flush?
We connect a flushing unit to the system, normally at the pump or across the boiler, and circulate water and cleaner under pressure, reversing the flow repeatedly. Each radiator is treated in turn, often with a magnet worked over the panel to break the sludge loose. The system is then flushed through, dosed with inhibitor and refilled.
Is it worth having a power flush?
It is worth it if radiators are cold at the bottom, the boiler is kettling, or a manufacturer has refused a warranty claim over system contamination. It is not worth it as an annual ritual, and anyone telling you every system needs one each year is selling. We will say plainly whether yours needs it.
What are the disadvantages of power flushing?
On an old system, flushing can open up leaks that the sludge was effectively plugging, most often at radiator valve unions or on panels corroded from the inside. It also takes most of a day with the heating off. It will not rescue a radiator that has already rusted through, and we will say so before we start rather than afterwards.