Radiators cold at the bottom — sludge and flow problems
Cold at the top usually means air and a bleed key fixes it. Cold at the bottom means solid iron oxide has settled where the water should circulate — and bleeding does nothing at all.
What magnetite does to a system
Steel radiators corrode slowly from the inside, shedding black magnetite that collects in low-velocity areas: radiator bases, the pump and the heat exchanger. Older open-vented systems in Somerset's stone cottages and Victorian terraces are especially prone because they draw in fresh oxygenated water through the feed and expansion tank.
Our approach, in order
- Thermal check of every radiator to map the affected circuit
- Chemical cleanse circulated before any mechanical flushing
- Powerflush or individual radiator flush depending on severity
- Magnetic filter fitted and inhibitor dosed to protect the repair
Frequently asked
- Can one radiator be flushed on its own?
- Yes — if only one or two are affected we can drop them, flush outside and rehang, which is cheaper than a full system flush.
- Does a new boiler need this first?
- Yes. Fitting a new boiler onto a dirty system risks blocking the new heat exchanger and can invalidate the manufacturer guarantee.
- How long does a powerflush take?
- A typical eight to ten radiator house takes most of a day.
Protect it afterwards
Cleansing without a filter and inhibitor just resets the clock. Both are included in how we quote so the system stays clean rather than silting up again in two winters.
Related solutions
Core services
Where we cover
New Worcester boiler with a 10 year guarantee*
Free no-obligation quotes for installation, servicing & repairs across BA & BS postcodes.